Network device, user device, and base station
Abstract
Problem to be solved.To provide a configuration for offloading data by a hybrid user device and a small node device. In this hybrid configuration, the small node device has a backhaul link to a long-range communication network and / or the Internet. The user device can send and receive data via the small node device using the backhaul link. [Selection diagram] Fig. 1

Term
10.4 yearsto projected expiry
Projected expiry 31 January 2037, counted from filing; an application has no term until it is granted.
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38 claims: 14 independent, 24 dependent
- 1第1の通信リンクを通して基地局から第1の制御プレーンメッセージを受信するように構成される第1の通信部と、 前記第1の制御プレーンメッセージに応じて確立された第2のリンクを通してユーザプレーンデータをユーザ装置に送信するように構成される第2の通信部と、 サーバからユーザプレーンデータを受信するように構成される第3の通信部と、を具備し、 前記第2の通信部から送信されるユーザプレーンデータは、前記ユーザ装置において、前記基地局から送信されるユーザプレーンデータと同時に受信され得ることを特徴とするネットワークデバイス。
- 2前記第1の通信リンクはX2インタフェースリンクであることを特徴とする請求項1に記載のネットワークデバイス。
- 3前記第1の通信部はさらに前記基地局から第2の制御プレーンメッセージを受信するように構成され、 前記第2の通信部は前記第2の制御プレーンメッセージに応じて前記第2の通信リンクを解放するように構成されることを特徴とする請求項1に記載のネットワークデバイス。
- 4前記第2の通信部はさらに前記基地局により設定された無線リソースで前記ユーザプレーンデータを送信するように構成されることを特徴とする請求項1に記載のネットワークデバイス。
- 5前記第2の通信リンクのセキュリティアソシエーションは前記基地局により制御されていることを特徴とする請求項1に記載のネットワークデバイス。
- 6前記第2の通信部はさらに前記基地局により設定された無線ベアラを用いて前記ユーザプレーンデータを送信するように構成されることを特徴とする請求項1に記載のネットワークデバイス。
- 7前記第1の通信部はさらに前記基地局から第3の制御プレーンメッセージを受信するように構成され、 前記第2の通信部はさらに前記第3の制御プレーンメッセージに応じてパイロット信号を前記ユーザ装置に送信して、前記ユーザ装置に前記パイロット信号を用いて前記第2の通信リンクの無線リンク品質を測定することを可能にさせるように構成されることを特徴とする請求項1に記載のネットワークデバイス。
- 8前記第2の通信部はさらに前記基地局によりパラメータが設定された物理レイヤ又はMACレイヤの無線リソースで前記ユーザプレーンデータを送信するように構成されることを特徴とする請求項1に記載のネットワークデバイス。
- 9前記第1の通信部はさらに前記基地局から第4の制御プレーンメッセージを受信するように構成され、 前記第2の通信部は前記第4の制御プレーンメッセージに応じて前記第2の通信リンクを再設定するように構成されることを特徴とする請求項1に記載のネットワークデバイス。
- 10前記第2の通信部はさらに前記第2の通信リンクを通して前記ユーザ装置から第3のユーザプレーンデータを受信し、前記第3のユーザプレーンデータを前記第3の通信部から前記サーバにアップロードするように構成されることを特徴とする請求項1に記載のネットワークデバイス。
- 11前記第3の通信部はサービングゲートウェイを介して前記サーバに接続するように構成されることを特徴とする請求項1に記載のネットワークデバイス。
- 12前記第1の通信部はさらに前記基地局から、ハンドオーバのための制御プレーンメッセージを受信するように構成されることを特徴とする請求項1に記載のネットワークデバイス。
- 13第1の通信リンクを通して基地局から制御プレーンデータ及び第1のユーザプレーンデータを受信するように構成される第1の通信部と、 第2の通信リンクを用いて、ネットワークデバイスを通してサーバから第2のユーザプレーンデータを受信するように構成される第2の通信部と、を具備し、 前記第1の通信部はさらに前記第1の通信リンクを通して前記基地局から第1の制御プレーンメッセージを受信するように構成され、 前記第2の通信部はさらに前記第1の制御プレーンメッセージに応じて前記第2の通信リンクを確立するように構成され、 前記第1のユーザプレーンデータと前記第2のユーザプレーンデータとを同時に受信することができることを特徴とするユーザ装置。
- 14前記第2の通信リンクのセキュリティアソシエーションは前記基地局により制御されていることを特徴とする請求項13に記載のユーザ装置。
- 15前記第1の通信部はさらに前記基地局から第2の制御プレーンメッセージを受信するように構成され、 前記第2の通信部は前記第2の制御プレーンメッセージに応じて前記第2の通信リンクを解放するように構成されることを特徴とする請求項13に記載のユーザ装置。
- 16前記第2の通信部はさらに前記基地局により設定された無線リソースで前記第2のユーザプレーンデータを受信するように構成されることを特徴とする請求項13に記載のユーザ装置。
- 17前記第2の通信部はさらに前記基地局によりパラメータが設定された物理レイヤ又はMACレイヤの無線リソースで前記第2のユーザプレーンデータを受信するように構成されることを特徴とする請求項13に記載のユーザ装置。
- 18前記第2の通信部はさらに前記基地局により設定された無線ベアラを用いて前記第2のユーザプレーンデータを受信するように構成されることを特徴とする請求項13に記載のユーザ装置。
- 19前記第1の通信部はさらに前記基地局から第3の制御プレーンメッセージを受信するように構成され、 前記第2の通信部はさらに前記ネットワークデバイスにより送信されるパイロット信号を受信して、前記パイロット信号の無線リンク品質を測定するように構成され、 前記パイロット信号の無線リソースは前記第3の制御プレーンメッセージに示されることを特徴とする請求項13に記載のユーザ装置。
- 20前記第2の通信部はさらに前記第2の通信リンクを用いて、前記ネットワークデバイスを通して第3のユーザプレーンデータを前記サーバに送信するように構成されることを特徴とする請求項13に記載のユーザ装置。
- 21前記第1の通信部はさらに前記基地局から第5の制御プレーンメッセージを受信するように構成され、 前記第2の通信部は前記第5の制御プレーンメッセージに応じて前記第2の通信リンクを再設定するように構成されることを特徴とする請求項13に記載のユーザ装置。
- 22第1の通信リンクを用いてユーザ装置とユーザプレーン及び制御プレーンデータをやり取りするように構成される第1の通信部と、 第2の通信リンクを用いてネットワークデバイスと制御プレーンデータをやり取りするように構成される第2の通信部と、 前記第1の通信リンクを用いて前記ユーザ装置に送信される第1の制御プレーンメッセージ又は、第2の通信リンクを用いて前記ネットワークデバイスに送信される第2の制御プレーンメッセージの少なくとも1つを通して、第3の通信リンクの確立及び解放/再設定/ハンドオーバを制御するように構成される制御部と、を具備し、 前記第1の通信部から送信されるユーザプレーンデータは、前記ユーザ装置において、前記ネットワークデバイスから第3の通信リンクを通して送信されるユーザプレーンデータと同時に受信され得ることを特徴とする基地局。
- 23前記制御部はさらに、前記第1の通信部により前記第1の通信リンクを用いて前記ユーザ装置に送信される第3の制御プレーンメッセージと、前記第2の通信部により前記第2の通信リンクを用いて前記ネットワークデバイスに送信される第4の制御プレーンメッセージとを用いて、前記第3の通信リンクの無線リソース割り当てを決定するように構成されることを特徴とする請求項22に記載の基地局。
- 24前記制御部はさらに、前記第1の通信部により前記ユーザ装置に送信される第5の制御プレーンメッセージと、前記第2の通信部により前記ネットワークデバイスに送信される第6の制御プレーンメッセージを用いて、前記第3の通信リンクの無線ベアラを割り当てることを特徴とする請求項22に記載の基地局。
- 25前記第1の通信部又は前記第2の通信部の少なくとも一つは、それぞれ前記ユーザ装置又は前記ネットワークデバイスから測定報告を受信するように構成され、 前記測定報告は前記第3の通信リンクの無線リンク品質の測定結果を含み、 前記制御部は前記測定報告に応じて、確立、解放、再設定、ハンドオーバ、及び無線リソース割り当てのうち少なくとも1つを決定することを特徴とする請求項22に記載の基地局。
- 26前記第1の通信リンクはX2インタフェースリンクであることを特徴とする請求項22に記載の基地局。
- 27前記第3の通信リンクのセキュリティアソシエーションを制御することを特徴とする請求項22に記載の基地局。
- 28無線通信システムにおいてネットワークデバイスを用いて通信を行う方法であって、 前記ネットワークデバイスで、第1の通信リンクを通して基地局から第1の制御プレーンメッセージを受信する工程と、 前記ネットワークデバイスが、前記第1の制御プレーンメッセージに応じてユーザ装置との間に第2の通信リンクを確立する工程と、 前記ネットワークデバイスで、サーバから下りユーザプレーンデータを受信する工程と、 前記ネットワークデバイスから、前記第2の通信リンクを通して前記下りユーザプレーンデータを前記ユーザ装置に送信する工程と、を具備し、 前記ネットワークデバイスから前記第2の通信リンクを通して送信される下りユーザプレーンデータは、前記ユーザ装置において、前記基地局から送信されるユーザプレーンデータと同時に受信され得ることを特徴とする方法。
- 29無線通信システムにおいてユーザ装置を用いて通信を行う方法であって、 前記ユーザ装置で、第1の通信リンクを通して基地局から第1の制御プレーンメッセージを受信する工程と、 前記ユーザ装置で、前記第1の制御プレーンメッセージに応じて第2の通信リンクを確立する工程と、 前記ユーザ装置で、前記第2の通信リンクを通して前記ネットワークデバイスから下りユーザプレーンデータを受信する工程と、を具備し、 前記ユーザ装置は、前記基地局から前記第1の通信リンクを通して送信される下りユーザプレーンデータと前記ネットワークデバイスから前記第2の通信リンクを通して送信される下りユーザプレーンデータとを同時に受信することができることを特徴とする方法。
- 30無線通信システムにおいてユーザ装置及びネットワークデバイスを制御するための基地局を用いて通信を行う方法であって、 前記基地局で、第1の通信リンクを用いて前記ユーザ装置とユーザプレーンデータ及び制御プレーンメッセージをやり取りし、第2の通信リンクを用いて前記ネットワークデバイスと制御プレーンメッセージをやり取りする工程と、 前記基地局で、前記第1の通信リンクを用いて前記ユーザ装置に送信される第1の制御プレーンメッセージ又は、第2の通信リンクを用いて前記ネットワークデバイスに送信される第2の制御プレーンメッセージの少なくとも1つを通して、第3の通信リンクの確立、解放、再設定及びハンドオーバを制御する工程と、を具備し、 前記第1の通信部から送信されるユーザプレーンデータは、前記ユーザ装置において、前記ネットワークデバイスから前記第2の通信リンクを通して送信されるユーザプレーンデータと同時に受信され得ることを特徴とする方法。
- 31第1の通信リンクを通して基地局から第1の制御プレーンメッセージ及び第2の制御プレーンメッセージを受信するように構成される第1の通信部と、 前記第1の制御プレーンメッセージに応じてユーザ装置との第2の通信リンクを確立するように構成され、さらに前記第2の制御プレーンメッセージに応じて少なくとも1つのパイロット信号を前記ユーザ装置に送信し、前記第2の通信リンクを通して前記ユーザ装置とユーザプレーンデータをやり取りするように構成される第2の通信部と、 サーバと前記ユーザプレーンデータをやり取りするように構成される第3の通信部とを具備し、 前記第2の通信部から送信されるユーザプレーンデータは、前記ユーザ装置において、前記基地局から送信されるユーザプレーンデータと同時に受信され得ることを特徴とするネットワークデバイス。
- 32前記第2の通信部はさらに前記第2の制御プレーンメッセージにより決定される送信周期、周波数領域リソース、時間領域リソース、及び符号領域リソースのうち少なくとも1つに従って前記少なくとも1つのパイロット信号を送信するように構成されることを特徴とする請求項31に記載のネットワークデバイス。
- 33前記パイロット信号が送信されるタイミングは、前記基地局と前記ユーザ装置の間の通信リンクのフレームタイミングを基準にしたオフセットにより設定されることを特徴とする請求項31に記載のネットワークデバイス。
- 34第1の通信リンクを通して基地局から制御プレーンデータメッセージ及び第1のユーザプレーンデータの両方を受信するように構成される第1の通信部と、 第2の通信リンクを用いて、前記ネットワークデバイスを通してサーバから第2のユーザプレーンデータを受信するように構成される第2の通信部と、を具備し、 前記第1の通信部はさらに前記第1の通信リンクを通して前記基地局から第1の制御プレーンメッセージを受信するように構成され、 前記第2の通信部はさらに前記第1の制御プレーンメッセージに応じて前記第2の通信リンクを確立するように構成され、 前記第2の通信部はさらに前記第2の通信リンクを通して前記ネットワークデバイスから少なくとも1つのパイロット信号を受信し、受信した前記少なくとも1つのパイロット信号を用いて前記第2の通信リンクの無線リンク品質を測定するように構成され、 前記第1の通信部はさらに前記第1の通信リンクを通して前記基地局に前記無線リンク品質を送信するように構成され、 前記第1のユーザプレーンデータと前記第2のユーザプレーンデータとを同時に受信することができることを特徴とするユーザ装置。
- 35前記第1の通信部はさらに前記基地局から第2の制御プレーンメッセージを受信し、前記パイロット信号に関する無線リソース情報は、前記第2の制御プレーンメッセージにより通知されることを特徴とする請求項34に記載のユーザ装置。
- 36前記パイロット信号が受信されるタイミングは、前記第1の通信リンクのフレームタイミングを基準にしたオフセットにより設定されることを特徴とする請求項34に記載のユーザ装置。
- 37第1の通信リンクを通して基地局から第1の制御プレーンメッセージを受信するように構成される第1の通信部と、 前記第1の制御プレーンメッセージに応じて確立された第2の通信リンクを通してユーザプレーンデータをユーザ装置に送信するように構成される第2の通信部と、 サーバから前記ユーザプレーンデータを受信するように構成される第3の通信部と、を具備し、 前記第2の通信部はさらに、処理負荷、無線リソース使用量、データレート、前記第2の通信リンクのパスロス、無線リンク品質、ブロックエラーレート、送信信号電力、受信信号電力、干渉電力、及び前記第2の通信リンクにおけるユーザ装置数のうち少なくとも1つを測定するように構成され、 前記第1の通信部はさらに前記測定の結果を前記基地局に送信するように構成され、 前記第2の通信部から送信されるユーザプレーンデータは、前記ユーザ装置において、前記基地局から送信されるユーザプレーンデータと同時に受信され得ることを特徴とするネットワークデバイス。
- 38第1の通信リンクを用いてユーザ装置とユーザプレーンデータ及び制御プレーンメッセージをやり取りするように構成される第1の通信部と、 第2の通信リンクを用いて前記ネットワークデバイスと制御プレーンメッセージをやり取りするように構成される第2の通信部と、 前記第1の通信リンクを用いて前記ユーザ装置に送信される第1の制御プレーンメッセージ又は、第2の通信リンクを用いて前記ネットワークデバイスに送信される第2の制御プレーンメッセージの少なくとも1つを通して、第3の通信リンクの確立、解放、再設定及びハンドオーバを制御するように構成される制御部とを具備し、 前記制御部はさらに第2の通信リンクにおける接続数、無線リソースの使用量、データレート、接続確立の成功率、ハンドオーバの成功率、無線リンクの故障数、ハンドオーバの回数、及び前記第2の通信リンクにおける接続再確立の回数のうち少なくとも1つを測定するように構成され、 前記第1の通信部から送信されるユーザプレーンデータは、前記ユーザ装置において、前記ネットワークデバイスから前記第3の通信リンクを通して送信されるユーザプレーンデータと同時に受信され得ることを特徴とする基地局。
Independent claims38
270 paragraphs, as filed
The present application relates to the operation of physical layers and link layers in mobile communication protocols.
One of the options for increasing the capacity of the wireless network is to increase the density (number of devices per unit area) of the base station or remote antenna unit to be deployed. As the density of the base station or remote antenna unit to be arranged increases, the cell capacity increases due to the frequency repetition effect. However, increasing the placement density involves some difficulties, and in particular, such placement units must be able to operate themselves as conventional base stations. These difficulties include:
(1) As the arrangement density increases, the user equipment changes its serving unit (base station) extremely frequently, so that the number of handovers increases. As a result, the quality of connectivity / mobility is expected to deteriorate. Therefore, the placement unit that increases the cellular capacity needs to have a high-precision linkage with the macro base station. (2) Conventional macro base stations transmit a plurality of required signals such as pilot signals, synchronization signals, broadcast signals, and paging signals, all of which may cause interference problems. Such interference limits the number of base stations deployed, which reduces cellular capacity. (3) Furthermore, the radio resource of the required signal of the conventional macro base station is usually static. Therefore, it is difficult to perform dynamic and efficient interference control by dynamically allocating radio resources, which also limits the number of base stations to be deployed and the corresponding cellular capacity. (4) The network operator needs to assign a cell ID or other cell-specific parameters to each cell. For example, the route sequence of a random accelerator channel in LTE Uplink (UL) is an example of such cell-specific parameters. Cell planning such as cell IDs and route sequences is complicated, and this also limits the number of base stations to be arranged and the corresponding cellular capacity. (5) The required cell capacity is unique to each area. For example, in urban areas, very large capacities are required, while in suburbs or rural areas, a relatively small increase in cell capacity is sufficient. In order to efficiently meet the needs of such different densities, the placement unit needs to be easy, low cost, and easy to install. (6) If the cost of each placement unit is high, the cost of the entire system will be extremely high if the placement density is increased. Therefore, in order to increase the cell capacity in a feasible way, the cost of the placement unit needs to be relatively low.
Various configurations have been proposed to increase the capacity of wireless networks. For example, a distributed base station using Remote Radio Head (RRH) technology communicates with a base station server using optical fiber. Since the base station server performs baseband processing, each RRH distributed base station operates as a power amplifier for the base station server. The higher the density of RRH distributed base stations, the more complex the baseband processing on the base station server. Therefore, the number of RRH cells corresponding to each distributed RRH base station is limited by the complexity of this RRH.
Another option to increase the capacity of the wireless network involves the use of picocells or femtocells. Unlike the RRH approach, baseband treatment is distributed across pico / femtocells. However, there is no high-precision linkage between the picocell / femtocell and the macrocell base station. Therefore, there is a possibility that the connectivity and mobility may not be sufficient because the conventional intra-frequency or inter-frequency handover is required between the pico cell / femto cell and the macro cell base station. Further, since the picocell / femtocell itself is also a base station, signals such as the pilot signal, synchronization signal, notification signal, and paging signal described above are transmitted. As a result, the placement density of pico / femtocells increases, and interference problems, difficulties in dynamic and efficient interference control, cell planning problems, and related problems cannot be solved.
Yet another option for increasing the capacity of wireless networks is the use of traditional WiFi. However, there is no link between the WiFi node and the macro cell base station. Therefore, dual macrocell and WiFi users are limited in connectivity and mobility. In addition, the use of WiFi in macrocell networks creates the complexity of assigning multiple IP addresses to a single user.
<p num="0007"> Therefore, there is a need for improved configurations and techniques in the art to increase the capacity of wireless networks.</p>
<p num="0008"> The present invention focuses on the physical (PHY) and link layer design of systems such as 3GPP's Long Term Evolution (LTE). The design uses device-to-UE (D2UE) and macro-to-UE (BS2UE) configurations, in which some functionality is maintained by the BS2UE link and others are supported by the D2UE link. Therefore, according to the present invention, it is possible to provide a wireless communication system that enables high capacity, high connectivity, low cost, and reduced planning complexity.</p><p num="0009"> The network device provided according to the first aspect of the disclosure comprises a first communication unit configured to receive a first control plane message from a base station through a first communication link, and said first control plane. A second communication unit configured to send user plane data to the user device through a second link established in response to a message, and a third communication configured to receive user plane data from the server. The user plane data transmitted from the second communication unit can be received at the same time as the user plane data transmitted from the base station in the user apparatus.</p><p num="0010"> The user equipment provided according to the second aspect of the disclosure includes a first communication unit configured to receive control plane data and a first user plane data from a base station through a first communication link, and a second communication unit. A second communication unit configured to receive a second user plane data from a server through a network device using the communication link of the above, and the first communication unit further includes the first communication unit. The second communication unit is configured to receive the first control plane message from the base station through the link, and the second communication unit is further configured to establish the second communication link in response to the first control plane message. The first user plane data and the second user plane data can be received at the same time.</p><p num="0011"> The base station provided in accordance with the third aspect of the disclosure is a second communication with a first communication unit configured to exchange user plane and control plane data with a user device using a first communication link. A second communication unit configured to exchange control plane data with a network device using a link, and a first control plane message or a first control plane message transmitted to the user device using the first communication link. A control unit configured to control the establishment and release / reset / handover of a third communication link through at least one of the second control plane messages transmitted to the network device using the second communication link. The user plane data transmitted from the first communication unit can be received at the same time as the user plane data transmitted from the network device through the third communication link in the user apparatus. And.</p>
<figref num="1">A configuration example of an extended local area wireless access system using a small node device is shown.</figref><figref num="2">The data path of any one small node device in the system of Figure 1 is shown.</figref><figref num="3">The flow of control plane and user plane data of the small node device of FIG. 2 is illustrated.</figref><figref num="4">An example of a configuration change in Figure 2 where a backhaul link from a small node device traverses the Internet is illustrated.</figref><figref num="5">The configuration which combined the features shown in the Examples of FIGS. 1 and 4 is illustrated.</figref><figref num="6">An example of a configuration change in Figure 5, including a gateway between the small node device and the core network / Internet, is illustrated.</figref><figref num="7">An example of a configuration change in FIG. 5 in which a backhaul link from a small node device passes through a network access gateway is illustrated.</figref><figref num="8">An example of a configuration modification in FIG. 5 in which a backhaul link from a small node device passes through a base station is illustrated.</figref><figref num="9">An example of a configuration modification in FIG. 6 is illustrated in which the backhaul link from the small node device passes through the central small node device.</figref><figref num="10">The time slots of the D2UE link and the BS2UE link of the user device are illustrated.</figref><figref num="11">A block diagram of an example of a small node device is shown.</figref><figref num="11A">A more detailed block diagram of an embodiment of a small node device is shown.</figref><figref num="12">A block diagram of an example of a user device is shown.</figref><figref num="13">A block diagram of an example of a base station is shown.</figref><figref num="14">The flowchart of the D2UE connection establishment method is shown.</figref><figref num="14A">The flow chart of the step shown in FIG. 14 is shown.</figref><figref num="15">The flow diagram of releasing the D2UE connection is shown.</figref><figref num="16">The flow diagram of the re-establishment of the D2UE link is shown.</figref><figref num="17">The flow diagram of the handover of the D2UE link is shown.</figref><figref num="17A">The flowchart of the user apparatus measurement technique which detects the existence of the closer adjacent small node device is shown.</figref><figref num="18">The flowchart of the call reception control method of a D2UE link is shown.</figref><figref num="19A">A mobile station that interferes with an adjacent base station is illustrated.</figref><figref num="19B">A mobile station that does not interfere with an adjacent base station is illustrated.</figref><figref num="20">A plurality of small node devices arranged around a base station are illustrated.</figref><figref num="21">The flowchart of the D2UE connection establishment method is shown.</figref><figref num="22">The time, frequency, and sign relationships between multiple D2UE pilot signals are illustrated.</figref><figref num="22A">Shows a D2UE link synchronized with a BS2UE link.</figref><figref num="22B">Shows the D2UE link offset in time with respect to the BS2UE link.</figref><figref num="22C">A plurality of cells, each having a plurality of small node devices, are illustrated.</figref><figref num="22D">The timing relationship between the D2UE link and the corresponding BS2UE link in a plurality of macro cell coverage areas is illustrated.</figref><figref num="22E">Shows D2UE pilot signals from multiple small node devices.</figref><figref num="22F">The pilot signal physical layer format is illustrated.</figref><figref num="22G">The timing relationship between a plurality of formatted pilot signals as shown in FIG. 22F is illustrated.</figref><figref num="22H">The graph of the received signal power of the pilot signal of FIG. 22G is shown.</figref><figref num="23">The flowchart of the D2UE establishment method according to the path loss measurement is shown.</figref><figref num="24">The flowchart of the D2UE handover method is shown.</figref><figref num="25">The flowchart of the D2UE link release method according to the path loss measurement is shown.</figref><figref num="26">An example of the configuration modification shown in FIG. 2 including the D2UE measurement data acquisition unit is illustrated.</figref><figref num="27">A table of D2UE measurement items is shown.</figref><figref num="27A">Illustration of status notification transmission in a small node device network.</figref><figref num="28">A table of traffic measurement items is shown.</figref>
Disclosed is a cellular network device that allows a user to offload traffic from a macrocell base station without the problems described above. Cellular network devices appropriately offload traffic from macro base stations and are referred to below as "small node devices." Small node devices allow the offloading of data traffic that would normally have to be done on the link between the macrocell base station and the UE (also referred to as the "BS2UE link"). If a small node device is deployed, offload data may be propagated through the small node device to UE link (also referred to as the "D2UE link"). Small node devices are similar to femto or pico base stations in that they can control radio resource allocation and transmission formats for D2UE links. However, the mobile station receives both user and control plane signaling from the femto / pico base station that performs the RRC process of the link between the mobile station and the femto / pico base station. In this regard, the femto / pico base station operates exactly as a conventional base station with respect to the user equipment. Therefore, the mobile station needs to perform a conventional handover from a femto / pico base station to another femto / pico base station, or from a macro base station to a femto / pico base station, and vice versa. When there are many such handovers, the quality of connectivity / mobility deteriorates. This is because the user equipment cannot communicate at the same time as the femto / pico base station and the macro base station, and the conventional intra-frequency or inter-frequency handover is required. In other words, traditional carrier aggregation operations cannot be performed between two different nodes, such as macro base stations and femto / pico base stations. On the other hand, the mobile station can simultaneously perform data transfer with the small node device disclosed in the present specification and data transfer with the macro base station. Macro base station to mobile station connection is a small node device to mobile station connection and data offload is executed It is maintained while it is done. As a result, high connectivity / mobility can be maintained even if the placement density is increased.
In addition, the femto / pico base station must transmit cell-specific reference signals (CRS), primary sync signals (PSS), secondary sync signals (SSS), and broadcast signals. Transmission of CRS / PSS / SSS / broadcast signals is problematic because the resulting cell-to-cell interference increases the placement density. On the other hand, since the mobile station acquires the control signaling of its own station from the macro base station, the small node device disclosed in this specification does not need to transmit the CRS / PSS / SSS / broadcast signal. Since the small node device exchanges user plane data with the mobile station in this way, it does not suffer from cell-to-cell interference as the placement density increases.
To offload this data traffic, the small node device has a backhaul link connected to the internet or core network and communicates with the server on the internet or core network. The backhaul link to the small node device is not limited to a wired connection to the Internet, but may be a wireless connection to the Internet such as WiFi or cellular connection. The server uses a backhaul link and a D2UE connection to transfer part of the data to the user device (or the data is transferred using a base station). The D2UE connection is controlled by a macro base station (hereinafter simply referred to as "base station"). More specifically, the base station controls the basic radio resource control of the D2UE connection such as connection establishment, handover, connection release, and call reception control. Furthermore, the BS2UE connection between the UE and the base station is maintained with the D2UE connection set. As a result, high-precision coordination is easily realized between the base station-to-UE (BS2UE) connection and the D2UE connection. Further, a plurality of functions essential for a conventional base station can be omitted in a small node device. For example, small node devices need only support the D2UE connection feature. Therefore, the cost and complexity of small node devices can be kept low. For example, complex operations of functions such as radio resource control (RRC) connection state control and non-access layer (NAS) control are performed by the base station. Therefore, some or most of the functionality of traditional Macro2UE links, such as broadcast channel transmission, pilot and sync signal transmission, and connection control, can be omitted in the D2UE connection.
The small node device is configured to support small node device to user device (D2UE) data transfer. Small node devices support base station to small node device links (BS2D links), and D2UE links are controlled by base stations via BS2D links. The UEs disclosed herein further support base station-to-user equipment links (BS2UE links) and D2UE links. The D2UE link is also controlled by the base station via the BS2UE link. Control signaling for the D2UE connection can be transmitted to the UE via the BS2UE connection. Similarly, control signaling for D2UE connections can be sent to small node devices over BS2D connections. In another embodiment, the D2UE connection may be similar to a D2D (UE to UE, or small node device to small node device) connection.
In order to achieve high connectivity, more important functions such as RRC connection state control and NAS control are maintained by the base station using BS2UE connection. More specifically, the radio interface control in the D2UE connection is performed by the BS2D and macrocell base station to user device (BS2UE) connections. This control includes connection establishment, connection management, reconfiguration, handover, connection release, radio resource selection management, power control, link adaptation, call reception control, wireless bearer allocation, traffic measurement, wireless measurement control, and bearer management. , Includes at least one of security associations, etc.
In another embodiment, the D2UE connection is maintained by a time domain duplex (TDD) physical layer design. In such an embodiment, in the band used for D2UE transmission, the user device and the small node device share the radio resource in time and use it on the band. <In yet another embodiment, the D2UE connection is maintained by frequency domain duplex (FDD) physical layer resource sharing instead of TDD. D2UE and BS2UE transmission can also be operated in different bands by utilizing the carrier aggregation function. The carrier aggregation function corresponds to a function that allows a transmitter and a receiver to transmit and receive signals at the same time in two or more carriers. In this way, D2UE transmission can operate in one band and BS2UE transmission can operate in other bands at the same time.
Alternatively, the D2UE and BS2UE transmissions can operate in different bands using the time division multiplexing function, in which case the D2UE transmissions occur only at the selected time and the BS2UE transmissions occur at the remaining time.
<System configuration> Examples of various small node devices will be described in detail. With reference to the drawing, FIG. 1 shows multiple small node devices or units 500 in a cellular communication system.<sub>1</sub>~500<sub>4</sub>Is shown. The system also includes base station 200 and user equipment (UE) 100.<sub>1</sub>、100<sub>2</sub>, And 100<sub>3</sub>And are included. As used herein, components with the same base component number have the same configuration, function and state (eg, 100) unless otherwise noted.<sub>1</sub>And 100<sub>2</sub>). In the system shown in Fig. 1, Evolved Universal Terrestrial Radio Access (E-UTRA) / Universal Terrestrial Radio Access Network (UTRAN) (also referred to as Long Term Evolution (LTE)) is applied, but WiMAX, WiFi, LTE-Advanced, etc. It is clear that various other radio protocols are also feasible in the system.
The base station 200 is connected to a higher layer station such as the access gateway device 300. On the other hand, the access gateway 300 is connected to the core network (CN) 400. The access gateway 300 is also called "MME / SGW" (Mobility Management Entity / Serving Gateway). The server 600 may connect to the core network 400.
The user device 100 communicates with the small node device 500 by device-to-user device (D2UE) communication. D2UE communication between the user device 100 and the small node device 500 is performed according to time division multiplexing (TDD). Alternatively, D2UE communication between the user device and the small node device 500 may be performed according to frequency division multiplexing (FDD). The D2UE link may be an LTE link or a simplified LTE link. However, it is clear that D2UE links may be implemented using non-LTE protocols such as LTE-Advanced, WiMax, WiFi, or other suitable protocols.
The small node device 500 communicates with the base station 200 using a base station to small node device (BS2D) link. For example, the BS2D link may include a wired X2 interface link. Alternatively, the BS2D link may be a wired link or a wireless link different from the X2 link. Alternatively, the BS2D link may be an improved version of the X2 interface. The improved version of the X2 interface link establishes a master-slave relationship between the base station 200 and the small node device 500. In some embodiments, the small node device 500 is connected to the core network 400 via a backhaul link to achieve greater capacity. These backhaul links are Ethernet® links, WiFi links, or cellular network links, respectively, and can be wired or wireless. Data plane traffic can thus flow between the core network 400 and the small node device 500 without overloading the base station 200. In this way, the user apparatus can access the data from the server 600 without the data passing through the base station 200. In other words, the small node device 500 uses D2UE communication to communicate with the user device 100 for the purpose of offloading data. In another embodiment, the small node device 500 may connect to the base station 200 instead of the core network 400. In this case, since the data processing in the lower layer such as the physical layer or the MAC layer is performed by the small node device 500, the data plane traffic flows into the base station 200, but the data processing of the base station 200 can be minimized. .. In contrast, control plane information and data plane traffic (eg, real-time data such as VoIP) can continue to flow to the UE 100 via the base station 200, access gateway 300, core network 400, and server 600. FIG. 2 is an abbreviated view of the system of FIG. 1, BS2UE connection or link 720, D2UE connection 7
FIG. 3 illustrates the data flow in the communication system of FIG. In this regard, there is a need for an entity that determines which data is offloaded through the small node device for the traditional interaction between the user equipment and the base station. Since base stations receive radio link quality reports from user equipment and / or small node devices, base stations are a natural candidate for making data partition decisions (ie, which data should be offloaded). .. However, other network nodes may make this decision. Refer to Figure 3 and suppose a decision is made to offload some data and not other data. The non-offload data is designated as data # 1, transferred from the access gateway device 300 to the base station 200 by the backhaul connection 740, and transmitted to the user device 100 over the downlink (DL) by the BS2UE connection 720. The same applies to the reverse uplink (UL). This data flow is transmitted as before. In addition to data # 1, offload data # 2 is transferred from the core network 400 to the small node device 500 by the backhaul connection 750 and to the user device 100 by DL via the D2UE connection 710. The same applies to the reverse UL. Since the control plane signaling is transmitted on the BS2D connection 730, the base station 200 can control the communication on the D2UE connection 710. Since the control signaling is also transmitted on the BS2UE connection 720, the base station 200 can control the communication on the D2UE connection 710. The control signaling of the BS2 UE connection 720 may be radio resource control (RRC) signaling. More specifically, data # 1 may include RRC signaling, NAS signaling, voice packets and the like, and data # 2 may include best effort packets, FTP data, web browsing packets and the like. That is, the data bearer may determine which type of data is to be transferred as data # 1 or data # 2. As a result, connectivity
FIG. 4 illustrates another embodiment in which the small node device 500 can connect to the server 610 via the Internet 410. In this case, the core network 400 may be regarded as a network controlled by a network operator. The core network 400 may include MME, S / P-GW, billing system nodes, customer database (HLS), and the like.
Although another embodiment is illustrated in FIG. 5, this may be regarded as a combination of the embodiments of FIGS. 1 and 4. In this embodiment, the extended user device 500 may be connected to the server 600 via the core network 400, or may be connected to the server 610 via the Internet. The small node device 500 can be connected to a network device, which network device may connect to the server 600 via the core network 400, or may connect to the server 610 via the Internet. The network device is an S-GW or P-GW in the core network, or another node. Alternatively, the network device can use the S-GW or P-GW in the core network, or another node. In another embodiment, as shown in FIG. 6, a gateway 310 is provided between the core network 400 / Internet 410 and the small node device 500.
The backhaul connection 750 may be modified as shown in FIG. 7 to connect the access gateway 300 and the small node device 500. Alternatively, as shown in FIG. 8, the backhaul connection 750 may connect the base station 200 and the small node device 500. In yet another embodiment, the backhaul connection 750 may connect the central small node device 510 and the small node device 500, as shown in FIG. The central small node device 510 may be connected to the Internet 410 and the core network 400 via a gateway 310 (selectable), or may be directly connected to these networks. If a central small node device 510 is included, the central small node device 510 may implement a layer sharing protocol that implements the RLC / PDCP layer while the remaining small node devices handle the physical / MAC layer. Other layer sharing methods may be implemented. For example, the central small node device 510 may implement the PDCP layer, while the remaining small node devices may implement the physical / MAC / RLC layer. The data bearer may determine whether data offload should be via a small node device. The data bearer may also determine whether the data flow should go through the small node device and the Internet 410 or the small node device and the core network 400. The data bearer may be of logical channel or logical channel type.
The carrier frequency in the D2UE connection 710 may be different from the carrier frequency in the BS2UE connection 720. Alternatively, the carrier frequency of the D2UE connection 710 may be the same as the carrier frequency of the BS2UE connection 720.
In the example below, without loss of generality, it is assumed that the carrier frequency in the D2UE connection is 3.5GHz and the TDD applies to the D2UE connection. Further, it is assumed that the carrier frequency in the BS2UE connection between the base station 200 and the user device 100 is 2 GHz, and the carrier frequency in the BS2D connection between the base station 200 and the small node device 500 is 2 GHz. At the beginning of this setting, the user apparatus 100 may send an RRC connection request to the base station 200. The base station sets BS2UE connection 720 accordingly. Alternatively, the base station 200 may send a paging signal to the user apparatus 100, and the user apparatus 100 sends an RRC connection request for the paging signal to the base station 200. The base station 200 sets up a BS2UE connection accordingly, and further sets up a connection between the user equipment 100 and the server 600 via the base station 200, the access gateway 300, and the core network 400.
Similarly, the base station 200 establishes a BS2D connection 730 between the base station 200 and the small node device 500. This setting may be permanently installed or established in the same way as the BS2UE connection. In some embodiments, the small node device 500 has the ability to reduce power or go to sleep when not in use. An embodiment of such a base station 200 is configured to send a wakeup signal to the small node device 500 using a BS2D connection 730 supported by X2 or other suitable protocol. In some embodiments, the LTE interface may be used in the protocol design. Further, the small node device can use a power saving mode such as a standby mode corresponding to the user device. In this case, the power saving mode may be released by the same method as that of the user apparatus 100, or may be executed according to a signal desired by the base station 200 or transmitted by the base station 200. The signal may be a paging signal or control signaling such as MAC control signaling or physical layer signaling.
As mentioned above, the BS2D connection 730 may always be configured between the base station 200 and the small node device 500. In such an always-setting embodiment, if the D2UE connection 710 is not set between the small node device 500 and the user device 100, the small node device 500 may enter the intermittent reception mode with the BS2D connection 730. .. In this case, if the D2UE connection 710 is not configured between the small node device 500 and the user device 100, the small node device 100 does not transmit a signal or transmits a signal very infrequently. For example, the small node device 500 lowers only the pilot signal so that the user device 100 can detect the small node device 500 even if the D2UE connection 710 is not configured between the small node device 500 and the user device 100. It may be sent at a frequency. The period of the pilot signal is, for example, 100 milliseconds, 1 second, or 10 seconds. Alternatively, the small node device 500 is from the base station 200 so that the user device 100 can detect the small node device 500 even if the D2UE connection 710 is not configured between the small node device 500 and the user device 100. Send a pilot signal based on the request.
After the links 720 and 730 are established, the base station 200 instructs the user apparatus 100 to set the D2UE connection 710 with the BS2UE connection 720 using control signaling. Further, the base station 200 instructs the small node device 500 to set the D2UE connection 710 with the BS2D connection 730 using the control signaling. Setting the D2UE connection 710 is also called establishing the D2UE connection 710.
In addition, base station 200 controls D2UE connection 710. For example, the base station 200 may instruct the user device 100 and the small node device 500 to reconfigure or reestablish the D2UE connection 710. Similarly, the base station 200 may instruct the user device 100 and the small node device 500 to release the D2UE connection 710. Further, the base station 200 may instruct the user apparatus 100 to hand over the D2UE connection to the small node device. More specifically, the base station 200 instructs the user apparatus 100 to perform a handover to another small node device on the carrier on which the D2UE connection 710 is executed. Base station 200 can control the above steps using RRC signaling on BS2UE connection 720 and / or BS2D connection 730.
If the D2UE connection is interrupted, the base station 200 uses the BS2UE connection 720 to maintain the connection between the user equipment 100 and the server 600.
Base station 200 also controls the radio resources of the D2UE connection 710. The details of the radio resource control of the D2UE connection 710 will be further described below. Alternatively, the small node device 500 may control the radio resources of the D2UE link. In yet another embodiment, both base station 200 and small node device 500 may control the radio resources of the D2UE link. In the following description, it is assumed that the base station 200 manages this radio resource without losing generality.
Base station 200 sets up one or more radio bearers for communication. The control signaling for configuring the wireless bearer is transmitted to the user device 100 over the BS2UE connection 720. Similarly, control signaling for configuring the radio bearer is transmitted to the small node device 500 over the BS2D connection 730.
The wireless bearer may be referred to as a "logical channel". Further, the base station 200 sets a wireless bearer for the BS2UE connection 720 and a wireless bearer for the D2UE connection 710. The wireless bearer of the BS2UE connection 720 may be the same as that used by the D2UE connection 710. Alternatively, the wireless bearer of the BS2UE connection 720 may be different from that used in the D2UE connection 710. For example, wireless bearers for packets for non-real-time services such as web browsing, email, and FTP can be configured with the D2UE connection 710. On the other hand, the wireless bearer of packets for real-time services such as VoIP and streaming can be set with BS2UE connection 720. Alternatively, the wireless bearer of the non-real-time service packet may be configured to support both the D2UE connection 710 and the BS2UE connection 720 so that the non-real-time service packet is preferentially transmitted on the D2UE connection 710. In yet another example, the wireless bearer of the real-time service packet is configured to support both the D2UE connection 710 and the BS2UE connection 720 so that the real-time service packet is preferentially transmitted on the BS2UE connection 720. .. The priority or priority of such packets can be set by base station 200. In this regard, the base station 200 can set either a D2UE connection 710 or a BS2UE connection 720 that should be preferentially used in communication with each wireless bearer.
Control plane (C plane) signaling, such as non-access layer (NAS) signaling and radio resource control (RRC) signaling, may be transmitted over the BS2UE connection 720. RRC signaling includes signaling messages such as establishing an RRC connection, invoking initial security, reconfiguring an RRC connection, releasing an RRC connection, reestablishing an RRC connection, configuring radio resources, measuring reports, and handover commands. included. The C-plane signaling radio bearer may be referred to as a "signaling radio bearer". C-plane signaling can also be sent over the D2UE connection 710. Alternatively, a part of the wireless bearer data may be transmitted by the D2UE connection 710, and the other part of the wireless bearer data may be transmitted by the BS2UE connection 720.
The small node device transmits common channels / signals such as primary sync signal (PSS), secondary sync signal (SSS), common reference signal, and broadcast channel over the D2UE connection 710. Alternatively, the small node device 500 does not transmit a common channel / signal, or transmits a common channel / signal very infrequently. For example, the small node device 500 transmits a pilot signal infrequently so that the user device 100 can detect the small node device. The period of the pilot signal is, for example, 1 second or 10 seconds. Alternatively, the small node device 500 may transmit a pilot signal based on a request from the base station 200 so that the user device 100 can detect the small node device 500.
The user device 100 simultaneously performs communication on the D2UE connection 710 and communication on the BS2UE connection 720. In one embodiment, the user device 100 uses the carrier aggregation function to simultaneously communicate via the D2UE connection 710 and the BS2UE connection 720. In this regard, the user apparatus 100 includes two radio frequency (RF) interfaces and simultaneously performs communication on the D2UE connection 710 and communication on the BS2UE connection 720. Alternatively, as shown in FIG. 10, the user apparatus 100 may perform communication on the D2UE connection 710 and communication on the BS2UE connection 720 according to time division multiplexing. Figure 10 shows the two sets of time slots, interval #A and interval #B. The user device 100 communicates in the time slot corresponding to the section #A in the BS2UE connection 720, and communicates in the time slot corresponding to the section #B in the D2UE connection 710.
Since the section of the D2UE connection is longer than that of the BS2UE connection, the effect of data offload can be improved. For example, the length of interval #A can be 8 milliseconds and the length of interval #B can be 1.28 seconds. The section of BS2UE connection 720 (section #A in FIG. 10) corresponds to the on-time in DRX control of BS2UE connection 720. The section of the D2UE connection 710 corresponds to the off time in the DRX control of the BS2UE connection 720. Off time means a DRX controlled sleep mode in which the user equipment 100 does not need to monitor the physical control channels transmitted from the base station 200 through the BS2UE connection 720. If the user device 100 uses time division multiplexing for connections 710 and 720, it is not necessary to support the ability to communicate simultaneously through these connections. That is, the user apparatus 100 can switch the RF interface from the BS2UE connection 720 to the RF interface of the D2UE connection 710, and vice versa. As a result, the cost / complexity of the user device 100 can be reduced.
Base station 200 controls the radio resources of the D2UE connection 710. Radio resources are selectively set in the time domain, frequency domain and code resource. For example, base station 200 may configure D2UE connection 710 so that non-overlapping spectra are used in all other D2UE connections. As a result, the problem of interference caused by other D2UE connections can be mitigated. Similarly, the base station 200 may be set so that the time resource in the D2UE connection 710 does not overlap with the time resource used in another D2UE connection. Alternatively, the base station 200 may be set so that the code resource in the D2UE connection 710 does not overlap with the code resource used in another D2UE connection. As a result, the problem of interference caused by other D2UE connections can be mitigated.
In another embodiment, some of the parameters of the radio resources of the D2UE connection 710 may be set by the base station 200, and other parameters may be set by the small node device 500. For example, the frequency domain resource of the D2UE connection 710 may be set by the base station 200, and the time domain resource of the D2UE connection 710 may be set by the small node device 500. Alternatively, the central carrier frequency of the D2UE connection 710 is set by the base station 200, and other frequency domain resources (such as the identification number of the resource block and the number of resource blocks) and the time domain resource of the D2UE connection 710 are set by the small node device 500. You may.
Alternatively, the base station 200 may configure a plurality of sets of radio resources for the D2UE connection 710, and the small node device 500 may configure one of the plurality of sets for the D2UE connection 710.
Base station 200 sends control signaling to user device 100 on BS2UE connection 720 and sets the radio resources of D2UE connection 710 as described above. In addition, base station 200 sends control signaling on BS2D connection 730 to small node device 500. And configure the radio resources for the D2UE connection 710 as described above.
Base station 200 controls the transmission power of DL in the D2UE connection 710. More specifically, the base station 200 may set the maximum transmission power of DL in the D2UE connection 710. Further, the base station 200 controls the transmission power of the UL in the D2UE connection 710. More specifically, the base station 200 may set the maximum transmission power of UL in the D2UE connection 710.
The base station 200 can set the maximum transmission power of UL or DL in the D2UE connection 710 based on the number of user devices in the cell in which the small node device provides the wireless communication service. For example, when the number of user devices in a cell is relatively small, the base station sets the maximum transmission power high. On the other hand, when the number of user devices in the cell is large, the base station sets the maximum transmission power low. As a result, the interference level of the carriers used in the D2UE connection 710 can be reduced by lowering the maximum transmission power in the high density arrangement. If there are not many user devices, the coverage area of the D2UE connection 710 can be expanded by increasing the maximum transmission power.
Alternatively, the base station 200 may set the maximum transmission power of the D2UE connection 710 based on the frequency at which communication is performed in the D2UE connection. More specifically, when the frequency of communication over the D2UE connection is relatively close to the frequency used by other systems, lowering the maximum transmit power can reduce the level of interference with the other system. it can. On the other hand, if the other system is not relatively close in the frequency domain, the coverage area of the D2UE connection can be expanded by increasing the maximum transmit power.
The user device 100 has the ability to measure and detect the closest small node device 500, thus maximizing the data throughput of the D2UE connection and minimizing the interference resulting from the D2UE connection. In addition, the user equipment has the ability to report the measurement results and the closest small node device detected to the base station. In contrast, base station 200 controls the D2UE connection based on the measurement results reported by the user equipment and the closest small node device detected. For example, if the ID of the nearest small node device changes, the base station causes the user device to stop communicating with the current serving small node device and communicate with the newly detected closest small node device. Can be ordered to start anew.
A block diagram of the small node device 500 is shown in FIG. In this embodiment, the small node device 500 includes a BS2D communication unit 502, a D2UE communication unit 504, and a backhaul communication unit 506. The BS2D communication unit 502, the D2UE communication unit 504, and the backhaul communication unit 506 are all connected to each other.
The BS2D communication unit 502 communicates with the base station 200 using the BS2D connection 730. More specifically, the BS2D communication unit 502 receives the control signaling of the D2UE connection 710 from the base station 200, and transmits the control signaling of the D2UE connection 710 to the base station 200. Control signaling includes signaling to establish / configure / reconfigure / reestablish / release the D2UE connection 710. This control signaling may include signaling of a D2UE connection handover. In some embodiments, the control signaling is RRC layer signaling in LTE. The control signaling is transmitted to the D2UE communication unit 504. The control signaling may include at least one parameter of the physical layer, MAC layer, RLC layer, PDCP layer, and RRC layer in the D2UE connection 710. The control signaling may include information on the radio bearer.
In addition, the control signaling may include radio resource control information for the D2UE connection 710. As described above, the radio resource control information of the D2UE connection 710 may include the radio resource information available in the D2UE connection 710, or may include the radio resource information not available in the D2UE connection. The radio resource is at least one of a time domain resource, a frequency domain resource, and a code domain resource. Radio resource control information may be sent to the D2UE connection.
In addition, the control signaling may include information on the link adaptation of the D2UE connection. More specifically, control signaling may be one of power control, adaptive modulation, and coding. The power control information may include information on the maximum transmit output power in the D2UE connection.
In another embodiment, the control signaling may include the measurement result of the D2UE connection 710. More specifically, the measurement result acquired by the D2UE communication unit 504 may be transmitted from the BS2UE communication unit 502. The measurement results include the UL radio link quality of the D2UE link, such as the path loss between the small node device and the user equipment, the UL received signal to interference ratio (SIR) of the D2UE link, and the UL interference power. The measurement for the user device may be for the user device currently connected via the D2UE connection, or for the user device currently not connected to the small node device using the D2UE connection. Alternatively, the measurement results include the quality of the radio link between the reported small node device and other small node devices.
The D2UE communication unit 504 communicates with the user device 100 using the D2UE connection 710. More specifically, the D2UE communication unit 504 establishes / sets / resets / reestablishes / releases the D2UE connection 710 between the small node device 500 and the user device 100. Management of this D2UE connection 710 can be performed based on the control signaling transmitted by the base station 200.
The D2UE communication unit 504 performs link adaptation of the D2UE connection 710 such as power control, adaptive modulation, and coding. Further, the D2UE communication unit 504 uses the D2UE connection 710 to transmit data to the small node device 500 and receive data from the small node device 500. As described above, some wireless bearer data may be transmitted over the D2UE connection 710.
Hereinafter, the data transferred from the user device 100 to the server 600 (or server 610) is referred to as "uplink data", and the data transferred from the server 600 (or server 610) to the user device 100 is referred to as "downlink data". Refer to. The D2UE communication unit 504 transmits downlink data to the user device 100 using the D2UE connection 710. The downlink data is transferred from the server 600 via the core network 400 and the backhaul communication unit 506. The D2UE communication unit 504 receives uplink data from the user device 100 via the D2UE connection 710. Then, the uplink data is transferred to the server 600 via the backhaul communication unit 506 and the core network 400. The D2UE communication unit 504 further measures the D2UE connection 710. More specifically, the D2UE communication unit 504 measures the radio link quality of the D2UE connection 710 between the small node device 500 and the user device 100. The radio link quality is at least one of UL's pilot signal received power, path loss, signal-to-interference ratio, channel state information, channel quality index, and received signal strength index on the D2UE connection 710. The wireless link quality can be calculated using the pilot signal transmitted from the currently connected user device. The path loss used is between the small node device 500 and the user device. The measurement may target the interference power level in the frequency band in which the D2UE communication operates. In another embodiment, the D2UE communication unit 504 may measure the quality of the wireless link between the small node device 500 and other small node devices. The D2UE communication unit 504 reports the measurement result to the base station 200 via the BS2D communication unit 502 and the BS2D connection 730.
The backhaul communication unit 506 is connected to the core network 400 via the backhaul link. The backhaul link may be a wired connection, a wireless connection, or a combination of a wired connection and a wireless connection. The wireless connection may be a connection provided by WiFi (wireless LAN) or a cellular system.
The backhaul communication unit 506 transmits the downlink data transferred from the core network 400 via the backhaul link to the D2UE communication unit 504. The backhaul communication unit 506 transmits uplink data (which is transferred from the D2UE communication unit 504) to the core network via the backhaul link.
Those skilled in the art will readily appreciate that the functional blocks shown in Figure 11 are equipped with the appropriate hardware and software. For example, Figure 11A shows an example of instantiation of these blocks. As shown in Figure 11A, the small node device 500 includes an RF interface 530 on the D2UE link. For example, data from the UE is received by antenna 520 connected to RF interface 530 over the D2UE link. RF interface 530 includes a duplexer that enables both receive and transmit functions at antenna 520. The baseband data transmitted to the UE is received from the baseband processor 535 on the RF interface 530. SERDES serializes baseband data and then converts it to analog format with a digital-to-analog converter (DAC). The resulting analog signal is then processed by the quadrature modulator and modulated to the desired carrier frequency. After passing through the bandpass filter and power amplifier (PA), the resulting RF signal is ready for transmission to the UE. Receiving data from the UE is similar except that the PA is replaced by a low noise amplifier (LNA) and the quadrature modulator is replaced by a quadrature demodulator. The resulting analog baseband data is then converted to digital format by an analog-to-digital converter (ADC) before being deserialized by SERDES.
In an embodiment where the BS2D link is a wireless link, the small node device 500 may include another RF interface similar to the RF interface 530 to provide services on the BS2D link. However, in the embodiment of FIG. 11A, a wired BS2D link is used. To service on such a link, the small node device 500 has a suitable interface card or circuit, such as Ethernet interface 540. Control signaling between the small node device and the base station passes through Ethernet interface 540 towards baseband processor 535.
In Figure 11A, the backhaul link is also a wired Ethernet link received on Ethernet interface 550. The downlink data from the backhaul link thus passes from the Ethernet interface to the baseband processor, which is controlled by the host microprocessor 560. The backhaul communication unit 506 of FIG. 11 thus maps the Ethernet interface 550 to the corresponding functions performed by the baseband processor 535 and the host microprocessor 560. Similarly, the BS2D communication unit 502 maps the Ethernet interface 540 to the corresponding functions performed by the baseband processor 535 and the host microprocessor 560. Finally, the D2UE communication unit 504 maps the RF interface 530 and the corresponding functions performed by the baseband processor 535 and the host microprocessor 560 to the antenna 520.
A block diagram of an embodiment of the user device 100 is shown in FIG. The user device 100 has a BS2UE communication unit 102 and a D2UE communication unit 104 connected to each other. The BS2UE communication unit 102 communicates with the base station 200 using the BS2UE connection 720. As explained above, some wireless bearer data is transmitted over the BS2UE connection 720. For example, control signaling such as RRC signaling, NAS signaling, and MAC layer signaling may be transmitted over the BS2UE connection 720. In addition, Voice over IP (VoIP) packets can be sent over a BS2UE connection 720. When the D2UE connection 710 is interrupted or unavailable, the BS2UE communication unit 102 transmits / receives data to / from the base station 200 and all wireless bearers. Further, the BS2UE communication unit 102 receives the control signaling of the D2UE connection 710 from the base station 200 and transmits the control signaling of the D2UE connection 710 to the base station 200. Such control signaling is the same as or similar to that described above in connection with the small node device 500 of FIG.
Control signaling is similar because it includes signaling to establish / configure / reconfigure / reestablish / release the D2UE connection 710. This control signaling may include signaling of a D2UE connection handover. Control signaling is RRC layer signaling in LTE. Alternatively, the control signaling may be LTE MAC layer signaling. In yet another embodiment, some of the control signaling is RRC signaling and the other is MAC layer signaling. The control signaling is transmitted to the D2UE communication unit 104. Control signaling may include at least one parameter of the physical layer, MAC layer, RLC layer, PDCP layer or RRC layer. The control signaling may include information on the radio bearer.
In addition, the control signaling may include radio resource control information for the D2UE connection 710. As described above, the radio resource control information of the D2UE connection 710 may include the radio resource information available in the D2UE connection 710, or may include the radio resource information not available in the D2UE connection. The radio resource is at least one of a time domain resource, a frequency domain resource, and a code domain resource. Radio resource control information may be transmitted for the D2UE connection.
In addition, the control signaling may include information on the link adaptation of the D2UE connection. More specifically, control signaling is one of power control and adaptive modulation and coding. The power control information may include information about the maximum transmit output power of the D2UE connection 710.
Finally, the control signaling may include the measurement result of the D2UE connection 710. More specifically, the measurement result acquired by the D2UE communication unit 104 may be transmitted from the BS2UE communication unit 102. The measurement results include path loss between the small node device and the user equipment, the received signal-to-interference ratio (SIR) in the DL of the D2UE link, and the radio link quality in the DL of the D2UE link such as DL interference power. The measurement of the small node device may be performed on the small node device currently connected, or may be performed on the adjacent small node device. The small node device currently connected is also referred to as "serving small node device". The wireless link quality of DL is described in more detail below.
The D2UE communication unit 104 communicates with the small node device 500 via the D2UE connection 710. More specifically, the D2UE communication unit 104 establishes / sets / resets / reestablishes / releases the D2UE connection 710 between the small node device 500 and the user device 100. Management of the D2UE connection 710 may be performed based on the control signaling transmitted by the base station 200. The D2UE communication unit 104 may perform link adaptation of the D2UE connection 710, such as power control, adaptive modulation, and coding. Further, the D2UE communication unit 104 transmits data to the small node device 500 by UL, and receives data from the small node device by DL by using the D2UE connection 710. As explained above, some wireless bearer data can be transmitted over the D2UE connection 710.
The D2UE communication unit 104 further measures the D2UE connection 710. More specifically, the D2UE communication unit 104 measures the DL radio link quality of the D2UE connection between the user device 100 and the currently connected small node device or adjacent small node device. DL radio link quality is at least one of pilot signal received power, path loss, signal-to-interference ratio, channel state information, channel quality index, and received signal strength index. The radio link quality can be calculated using the pilot signal transmitted from the serving small node device or an adjacent small node device. The path loss used is between the user device and 100 and the serving small node device or the adjacent small node device. The D2UE communication unit 104 reports the measurement result to the base station 200 via the BS2UE communication unit 102 and the BS2UE connection 720.
A block diagram of an example of the base station 200 is shown in FIG. The base station 200 includes a BS2UE communication unit 201, a BS2D communication unit 202, a D2UE communication control unit 204, and a backhaul communication unit 206, all of which are connected to each other.
The BS2UE communication unit 201 communicates with the user device using the BS2UE connection 720. As explained above, some wireless bearer data is transmitted over the BS2UE connection 720. For example, control signaling such as RRC signaling, NAS signaling, and MAC layer signaling may be transmitted over the BS2UE connection 720. In addition, Voice over IP (VoIP) packets can be sent over a BS2UE connection 720. Data from other data bearers may be transmitted over a BS2UE connection 720.
As described above, when the D2UE connection 710 is interrupted or cannot be used, the BS2UE communication unit 201 transmits / receives data to / from the user device 100 and all wireless bearers. A part of data such as U plane data transmitted from the user device 100 is transferred to the core network 400 via the BS2UE communication unit 201 and the backhaul communication unit 206. The U-plane data transmitted from the core network 400 is transferred to the user apparatus 100 via the backhaul communication unit 206 and the BS2UE communication unit 201.
Further, the BS2UE communication unit 201 receives the control signaling of the D2UE connection 710 from the user device 100 and transmits the control signaling of the D2UE connection 710 to the user device 100. Since this control signaling is the same as that for the user apparatus 100, the description thereof will be omitted below.
The BS2D communication unit 202 communicates with the small node device 500 using the BS2D connection 730. The BS2D communication unit 202 receives the control signaling of the D2UE connection 710 from the small node device 500, and transmits the control signaling of the D2UE connection 710 to the small node device 500. Since this control signaling is the same as that for the small node device 500, the description thereof will be omitted below.
The control signaling of the D2UE connection 710 is generated by the D2UE communication control unit 204 as described later, and is transferred to the user device 100 via the BS2UE communication unit 201. The control signaling is also transmitted to the small node device via the BS2D communication unit 202.
The D2UE communication control unit 204 controls the wireless link connection of the D2UE connection 710. Wireless link connection control includes at least one of the establishment / configuration / reconfiguration / reconfiguration / reestablishment / release of the D2UE connection 710. The parameters of the wireless link connection control are transmitted to the user device 100 via the BS2UE communication unit 201, and are transmitted to the small node device 500 via the BS2D communication unit 202. This parameter includes at least one of the physical layer, MAC layer, RLC layer, PDCP layer, and RRC layer parameters. The parameters include radio bearer information. In this specification, wireless link connection control is also referred to as "radio resource control".
More specifically, when the path loss between the user device 100 and the small node device 500 is larger than the threshold value, the D2UE communication control unit 204 determines that the D2UE connection 710 should be released. For example, the D2UE communication control unit 204 may send control signaling to release the D2UE connection 710. The D2UE communication control unit can make such a decision based on the measurement report transmitted from at least one of the user device 100 and the small node device 500. More specifically, at least one of the user device 100 and the small node device 500 determines whether or not the path loss is larger than the threshold value, and sends a measurement report when the path loss is larger than the threshold value. After receiving the measurement report, the D2UE communication control unit 204 may send control signaling to at least one of the small user device 100 and the small node device 500. In the above example, the DL transmission power or UL transmission power in the D2UE connection 710 may be used instead of the path loss.
The D2UE communication control unit 204 controls the handover of the D2UE connection between the user device 100 and the small node device 500. More specifically, the D2UE communication control unit 204 receives the measurement report from the small node device 500 and determines whether or not the user device 100 should hand over to a closer adjacent small node device. Here, the "serving small node device" refers to a small node device that currently has a D2UE connection with the user device.
In addition to this, the D2UE communication control unit 204 controls the radio resources of the D2UE connection. More specifically, the D2UE communication control unit 204 allocates radio resources for the D2UE connection so as not to interfere with other D2UE connections and not to be interfered with by other D2UE connections. Thus, the radio resources in one D2UE connection do not overlap with the rest of the D2UE connections. Radio resources can be presented to user equipment and small node devices by radio resource control parameters. The parameters include at least one of the frequency domain resource ID, the time domain resource ID, and the code domain resource ID. The radio resources allocated to the D2UE connection may be determined based on the number of user devices in the cell of the serving small node device or the interference level in the operating frequency band of the D2UE communication.
Further, the D2UE communication control unit 204 may control the link adaptation of the D2UE connection 710. More specifically, link adaptation is one of power control, and adaptive modulation and coding. The power control information may include information about the maximum transmit output power of the DL or UL of the D2UE connection 710.
The control signaling determined based on the control in the D2UE communication control unit 204 is transmitted to the user device via the BS2UE communication unit 201. The control signaling is transmitted to the small node device via the BS2D communication unit 202.
The backhaul communication unit 206 supplies the downlink data received from the core network 400 to the BS2UE communication unit 201. Similarly, the BS2UE communication unit 201 supplies uplink data to the backhaul communication unit 206, and the backhaul communication unit 206 transmits this uplink data to the core network 400.
Those skilled in the art will readily appreciate that the functional blocks of user equipment 100 and base station 200 shown in FIGS. 12 and 13, respectively, are mapped to components similar to those described for user equipment 500. For example, the user equipment requires two similar RF interfaces for the Macro2D communication unit 102 and the D2D communication unit 104. These RF interfaces work with suitable processors such as baseband processors and host microprocessors.
The operation of the mobile communication system described herein is more clearly understood with reference to the flowchart for establishing a connection in response to the generation of traffic data to be transmitted, shown in FIGS. 14 and 14A. The flowchart begins with the generation of traffic data, which is uplink and / or downlink data, in step S801. For example, traffic data corresponds to sending and receiving e-mails, browsing websites, downloading files, or uploading files.
In step S802, an LTE connection (BS2UE connection 720) is established between the base station 200 and the user equipment 100. If the connection is triggered by the user device, the user device can initiate the connection in a random access process. If the connection is triggered by server 600, the base station may send a paging message to initiate the connection. Step S802 corresponds to step A802 in Figure 14A.
In the embodiments of FIGS. 14 and 14A, it is assumed that the BS2D connection 730 is always configured between the base station 200 and the small node device 500. However, in other embodiments, the connection between the base station 200 and the small node device 500 (BS2D connection 730) is established at or immediately after step S802. The establishment may be triggered by base station 200 using control signaling. Further, the small node device 500 may start transmitting the pilot signal of the D2UE connection 710 after receiving the request from the base station 200 in the above establishment step. As a result, when the pilot signal is not transmitted, serious interference with other communications in the frequency band does not occur.
In step S803, user device 100 measures the D2UE connection. In particular, the user device 100 measures the DL radio link quality in a D2UE connection. More specifically, the user apparatus 100 transmits a measurement report to the base station informing the base station of the identification number of the small node device having the best DL radio link quality.
In one embodimentD2UEConnection measurement is shown in the figure14ASteps ofA803a,A803b,as well asA803cIt may be done as illustrated in. StepA803aAnd the base stationBS2UEConnection720Sends control signaling to the user device withD2UEBy instructing the measurement of the connection, the user equipment detects the small node device with the best wireless link quality.
Control signaling may include measurement information. For example, the control signaling may include at least one of the carrier frequency of the D2UE connection, the bandwidth of the D2UE connection, the identification number of the small node device, the measurement information, the information of the pilot signal transmitted by the small node device, and so on. Good. RSRP or RSRQ indicators can be used for information about the measurements. The information of the pilot signal may be related to the radio resource of the pilot signal. More specifically, the pilot signal information is at least one of the transmission cycle of the pilot signal, the frequency domain resource information of the pilot signal, the time domain resource information of the pilot signal, and the like. As further described, the time offset between the D2UE connection and the BS2UE connection may be included in the pilot signal information. Further, the transmission power of the pilot signal may be included in the information of the pilot signal.
Further, the measurement information may include a rule for sending the measurement report to the base station 200. This rule may include criteria similar to those in LTE, such as Event A1, A2, A3, A4, and A5 as defined in TS36.331. The measurement information may include a threshold value, a layer-3 filtering coefficient, a trigger time, and the like. In addition to this, cell selection / reselection control signaling may be further included in the measurement information. For example, control signaling for idle mode measurements may be further included in the measurement information.
The control signaling can be transmitted by individual control signaling or broadcast information.
The control signaling in step S803 may include an indicator of whether or not a D2UE connection is available in the cell where the base station 200 provides the wireless communication system to the user equipment 100. Control signaling may be transmitted in step A802 instead of step A803a.
At step A803b, user equipment 100 measures the DL radio link quality in the D2UE connection.
In step A803c, user equipment 100 sends a measurement report to base station 200 over BS2UE connection 720 informing base station 200 of the identification number of the small node device with the best DL radio link quality.
In step S804, a D2UE connection (D2UE connection 710) is established between the user device and the small node device. The base station commands the user equipment and the small node device to set up the D2UE connection 710. The parameters of the D2UE connection 710 are transmitted from the base station 200 to the user device 100 and the small node device 500 by the BS2UE connection 720 and the BS2D connection 730, respectively. In addition, the establishment of the D2UE connection 710 is reported to base station 200 by user equipment 100 and / or small node devices. Step S804 corresponds to steps A804a through A804f in FIG. 14A. In other words, the establishment of the D2UE connection 710 can be done as illustrated in steps A804a, A804b, A804c, A804d, A804e, and A804f of FIG. 14A.
In step A804a, base station 200 sends control signaling to the small node device 500 over the BS2D connection 730, instructing the small node device 500 to establish the user equipment 100 and the D2UE connection 710. In general, this small node device is a small node device with the best DL radio link quality based on measurement reports. At step A804b, the small node device 500 can send a response to the receive control signaling from step A804a. The control signaling may include at least one of the identification number of the user apparatus 100, the capability information of the user apparatus 100, and the like.
In step A804c, base station 200 sends control signaling to user device 100 over BS2UE connection 720, instructing user device 100 to establish a small node device 500 and a D2UE connection 710. For example, the control signaling in step A804c may include at least one of the following parameters:
-Wireless bearer information for D2UE connection 710 -D2UE connection 710 carrier frequency information -D2UE connection 710 frequency band index -System bandwidth (channel bandwidth) of D2UE connection 710 -D2UE connection 710 prohibited cell information -Identification number of small node device 500 -UL maximum transmit power of D2UE connection 710 -DL and UL slot information for D2UE connection 710 (for TDD) -Random access channel information for D2UE connection 710 -Uplink physical control channel information such as PUCCH for D2UE connection 710 -D2UE connection 710 downlink physical control channel information such as PDCCH and PHICH -D2UE connection 710 uplink physical shared channel information -D2UE connection 710 downlink physical shared channel information -Uplink sounding reference signal information for D2UE connection 710 -D2UE connection 710 uplink power control information information -D2UE connection 710 downlink or uplink cyclic prefix information information -Time alignment control information on the uplink of D2UE connection 710 -Information on RLC or PDCP configuration of each wireless bearer of D2UE connection 710 -MAC configuration information for D2UE connection 710 -Security information for D2UE connection 710
Part or all of the information in step A804c may be transmitted to the small node device 500 in step A804a.
The radio bearer information may indicate which type of radio bearer should be set for the D2UE connection 710 and which priority should be specified for each radio bearer. Since the parameters of the D2UE connection 710 can also be transmitted in step A804c, the small node device 500 does not necessarily have to transmit the broadcast channel, which reduces the complexity of the small node device.
At step A804d, user device 100 sends control signaling to establish a connection (D2UE connection 710) between user device 100 and the small node device 500. The control signaling may be random access signaling. Alternatively, the control signaling may be pre-allocated access signaling. The pre-allocated access signaling radio resource information may be transmitted to the user apparatus 100 by the base station 200 in step A804c.
The radio resource information of the access signaling assigned in advance may be set by the base station 200. In this case, the base station 200 notifies the small node device 500 of the radio resource information in step A804a. Alternatively, the radio resource information of the access signaling assigned in advance may be set by the small node device 500. In such an embodiment, the small node device 500 notifies the base station 200 of the radio resource information in step A804b .
In step A804e, the small node device 500 sends a response to the control signaling sent in step A804d. As a result, a D2UE connection 710 can be established.
In step A804f, user equipment 100 sends control signaling to base station 200 to notify base station 200 that the D2UE connection 710 has been successfully established.
In step S805, as described above with reference to FIG. 3, some of the traffic data (eg, data # 2 in FIG. 3) goes through the D2UE connection 710 and the small node device 500 to the user equipment 100 and server 600. Transferred to and from. The data transmitted by the D2UE connection 710 is, for example, a part of the data of the wireless bearer set for communication between the user device 100 and the server 600. More specifically, the data transferred over the D2UE connection 710 is at least one of best effort packets, non-real-time service packets, and real-time service packets. The data transferred over the D2UE connection 710 includes U-plane data. Step S805 corresponds to step A805 in Figure 14A.
In step S806, as described above with reference to FIG. 3, some of the traffic data (eg, data # 1 in FIG. 3) is connected to the user equipment 100 and the server 600 via the BS2UE connection 720 and the base station 200. Transferred between. C-plane data may be transmitted via BS2UE connection 720 instead of D2UE connection 710. Step S806 corresponds to step A806 in FIG. 14A.
The operation shown in FIG. 14 may be described as an operation of the small node device 500 as follows. The operation of the small node device 500 is one of the establishment of the D2UE connection 710 with the user device 100 (step S804) (step S804) and the data transferred between the user device 100 and the server 600 using the D2UE connection 710. Includes part transfer (step S805).
The operation shown in FIG. 14 may be described as an operation of the user device 100 as follows. The operation of the user device 100 is to establish an LTE connection (BS2UE connection 720) with the base station 200 (step S802), measure a small node device (step S803), and establish a D2UE connection 710 with the small node device 500 (step S802). Step S804) and a portion of the data (transferred between the user device 100 and the server 600) via the D2UE connection 710 and the small node device 500 (step S805) and a portion of the data (transferred). Includes transfer (transferred between user equipment 100 and server 600) via BS2UE connection 720 and base station 200 (step S806).
The process shown in FIG. 14 may be described as an operation of the base station 200 as follows. The operation of the base station 200 uses the establishment of the LTE connection (BS2UE connection 720) with the user apparatus 100 (step S802), the control signaling for establishing the D2UE connection 710 (step S804), and the BS2UE connection 720. Includes the transfer (step S806) of a portion of the data (transferred between the user apparatus 100 and the server 600). In the D2UE connection 710, a part of the data (transferred between the user device 100 and the server 600) is transferred via the D2UE connection 710 and the small node device 500.
The operation of the mobile communication system according to the embodiment will be described with reference to FIG. In step S901, a portion of the traffic data is transferred between the user equipment 100 and the server 600 via the D2UE connection 710 and the small node device 500. In step S902, a part of the traffic data is transferred between the user apparatus 100 and the server 600 via the BS2UE connection 720 and the base station 200. Steps S901 and S902 are the same as steps S805 and S806, respectively, and specifically steps S901 and S902 may be a continuation of steps S805 and S806.
In step S903, there is no more traffic data between user equipment 100 and server 600. More specifically, step S903 corresponds to the end of sending and receiving e-mail, browsing a website, downloading a file, or uploading a file.
In step S904, base station 200 sends control signaling to the small node device 500 to notify the small node device 500 that the D2UE connection 710 should be released. In step S905, the small node device 500 sends a response to the notification in step S904.
In step S906, base station 200 sends control signaling to user equipment 100 to notify user equipment 100 that the D2UE connection 710 should be released. In step S907, user apparatus 100 sends a response to the notification in step S906. Steps S906 and S907 may be performed before steps S904 and S905. Alternatively, steps S906 and S907 may be executed at the same time as steps S904 and S905.
The D2UE connection 710 is released in step S908 in response to the control signaling in steps S904 and S906. Steps S905 and S907 may be performed after step S908 so that user equipment 100 or small node device 500 can report that the D2UE connection 710 has been released.
In step S909, the base station 200 sends control signaling to the user apparatus 100 to notify the user apparatus 100 that the BS2UE connection 720 has been released. In step S910, user apparatus 100 sends a response to the control signaling in step S909 to base station 200. Steps S909 and S910 correspond to the normal process of releasing the LTE connection.
In the embodiment described with reference to FIG. 15, the base station 200 transmits control signaling to instruct the release of the D2UE connection 710. However, in yet another embodiment, the user device 100 or the small node device 500 may transmit control signaling.
The process shown in FIG. 15 may be described as an operation performed by the small node device 500 as follows. The operation of the small node device 500 is the transfer of a part of the data (transferred between the user device 100 and the server 600) using the D2UE connection 710 (step S901) and the control transmitted from the base station 200. It may include receiving signaling (step S904), sending a response to control signaling to base station 200 (step S905), and releasing the D2UE connection 710 with user equipment 100 (step S908).
The process shown in FIG. 15 may be described as an operation performed by the user apparatus 100 as follows. The operations of the user device 100 include the transfer of part of the data (transferred between the user device 100 and the server 600) via the D2UE connection 710 and the small node device 500 (step S901), and the BS2UE connection 720 and Transferring a portion of the data through base station 200 (transferred between user device 100 and server 600) (step S902) and receiving control signaling transmitted by base station 200 (step S906). , Sending the response to the control signaling to base station 200 (step S907), releasing the D2UE connection 710 with the user equipment 100 (step S908), and releasing the LTE connection (BS2UE connection 720) in steps S909 and S910. including.
The process shown in FIG. 15 may be described as an operation performed by the base station 200 as follows. The operations of base station 200 include transmission of control signaling to the small node device 500 for release of D2UE connection 710 (step S904) and transmission of control signaling to user equipment 100 for release of D2UE connection 710 (step S904). Includes S906) and release of BS2UE connection 720 (steps S909 and S910).
The operation of the mobile communication system according to another embodiment will be described with reference to FIG. In step S1001, some of the traffic data is transferred between the user equipment 100 and the server 600 via the D2UE connection 710 and the small node device 500. In step S1002, part of the traffic data is transferred between the user equipment 100 and the server 600 via the BS2UE connection 720 and the base station 200. Steps S1001 and S1002 may be the same as steps S805 and S806, respectively, and specifically steps S1001 and S1002 may be a continuation of steps S805 and S806.
In step S1004, base station 200 sends control signaling to the small node device 500 to notify the small node device 500 that the D2UE connection 710 should be reconfigured. In step S1005, base station 200 sends control signaling to user equipment 100 to notify user equipment 100 that the D2UE connection 710 should be reconfigured. More specifically, the parameters described in step A804c may be included in the control signaling in step 1004 or step S1005.
At step S1006, the D2UE connection 710 is reconfigured. More specifically, some of the parameters of the D2UE connection 710 are changed. These parameters include frequency domain resource parameters, time domain resource parameters, code domain resource parameters, pilot signal parameters for D2UE connection 710, initial access parameters for D2UE connection 710, radio bearer parameters, and D2UE connection 710. Contains at least one of the power control parameters of. The power control parameters include information on the maximum transmit output power of DL or UL on the D2UE connection 710.
In step S1007, the small node device 500 sends control signaling to base station 200 to notify base station 200 that the D2UE connection 710 has been successfully reconfigured. In step S1008, user apparatus 100 sends control signaling to base station 200 to notify base station 200 that the D2UE connection 710 has been successfully reconfigured.
The process shown in FIG. 16 may be described as an operation of the small node device 500 as follows. The operation of the small node device 500 is to transfer a part of the data transferred between the user device 100 and the server 600 using the D2UE connection 710 (step S1001) and the control signaling to reconfigure the D2UE connection 710. (Step S1004), reconfiguring the D2UE connection 710 (step S1006), and transmitting control signaling to report that the D2UE connection 710 has been reconfigured (step S1008).
The process shown in FIG. 16 may be described as an operation of the user apparatus 100 as follows. The operation of the user device 100 is the transfer of a part of the data transferred between the user device 100 and the server 600 using the D2UE connection 710 (step S1001) and the user device using the BS2UE connection 720. Transfer of some of the data transferred between 100 and the server 600 (step S1002), receive control signaling to reconfigure the D2UE connection 710 (step S1005), and reconfigure the D2UE connection 710 (step S1006). And the transmission of control signaling (step S1008) reporting that the D2UE connection 710 has been reconfigured.
The process shown in FIG. 16 may be described as an operation of the base station 200 as follows. The operation of base station 200 is the transfer of part of the data transferred between the user equipment 100 and the server 600 using the BS2UE connection 720 (step S1002) and the control signaling to reconfigure the D2UE connection 710. Transmission to the small node device 500 (step S1003), transmission of control signaling to the user device 100 to reconfigure the D2UE connection 710 (step S1004), and control signaling to report that the D2UE connection 710 has been reconfigured. Includes reception (step S1007) and reception of control signaling reporting that the D2UE connection 710 has been reconfigured (step S1008).
The operation of the mobile communication system according to another embodiment will be described with reference to FIG. In step S1101, some of the traffic data is transferred between the user equipment 100 and the server 600 via the D2UE connection 710 and the source small node device 500. In step S1102, part of the traffic data is transferred between the user equipment 100 and the server 600 via the BS2UE connection 720 and the base station 200. Steps S1101 and S1102 may be the same as steps S805 and S806, respectively, and specifically steps S1101 and S1102 may be a continuation of steps S805 and S806.
In step S1103, user device 100 measures the D2UE connection as described below. That is, the user device 100 measures the DL radio link quality of the serving small node device and the adjacent small node device. DL radio link quality is at least one of pilot signal received power, path loss, signal-to-interference ratio (SIR), channel state information, channel quality index, and received signal strength index.
More specifically, as illustrated in FIG. 17A, the user device 100 determines whether or not an adjacent small node device closer to the user device 100 than the serving small node device has been detected, and the adjacent small node device is detected. If so, the measurement report is sent to the base station. At step A1103a, user device 100 measures the D2UE connection.
In step A1103b, user device 100 determines if an adjacent small node device closer to the user device than the serving small node device has been detected. The serving small node device means a small node device (source small node device) currently communicating with the user device. More specifically, when the adjacent small node device has a higher radio link quality than the serving small node device, it is determined that the adjacent small node device is closer to the user device than the serving small node device.
If the adjacent small node device is closer to the user device than the serving small node device (step A1103b: YES), the user device sends a measurement report to the base station to notify the base station that the adjacent small node device has been detected. To do. Step A1103b corresponds to step S1104 in FIG.
If the adjacent small node device is not closer to the user device than the serving small node device (step A1103b: NO), the user device does not send the measurement report to the base station. Steps A1103a and A1103b correspond to step S1103 in FIG.
In step S1104, the user equipment sends a measurement report to the base station, notifying the base station that a closer adjacent small node device has been detected. Hereinafter, the serving small node device is referred to as a "source small node device", and the adjacent small node device is referred to as a "target small node device".
In step S1105, the base station determines that the user equipment should be handed over to an adjacent small node device (target small node device).
At step S1106, the base station sends control signaling to the target small node device in preparation for the handover. This control signaling may be referred to as a "D2UE connection handover request". More specifically, the base station notifies the target small node device of the parameters for the target small node device to establish a D2UE connection with the user device. The parameters described in step A804a may be included in the control signaling in step S1106.
At step S1107, the target small node device sends a response to the control signaling in step S1106.
In step S1108, base station 200 sends control signaling to the user equipment, instructing the user equipment to perform a handover to the target small node device. The control signaling may include the connection information of the D2UE connection 710. More specifically, the connection information includes at least one of the measurement settings of the D2UE connection 710, the mobility control information of the D2UE connection 71, the radio resource control information of the D2UE connection 710, and the like.
Further, the radio resource control information of the D2UE connection 710 includes the radio bearer information of the D2UE connection 710, the PDCP layer configuration information of the D2UE connection 710, the RLC layer configuration information of the D2UE connection 710, and the MAC layer configuration information of the D2UE connection 710. It may include at least one of the physical layer configuration information in the D2UE connection 710. More specifically, the parameters described in step A804c may be included in the radio resource control information of the D2UE connection 710.
In step S1109, the base station 200 sends control signaling to the source subnode device 500 to notify the source subnode device 500 that the user apparatus 100 should hand over to the target subnode device. The source small node device 500 terminates communication with the user device 100 based on control signaling. Specifically, the source small node device releases the D2UE connection 710.
At step S1110, the user device sends control signaling to establish a connection between the user device and the target small node device. The control signaling may be random access signaling and may be the same as in step A804c.
In step S1111 the target small node device 500 sends a response to the control signaling sent in step S1110. As a result, a D2UE connection can be established between the user device 100 and the target small node device.
In step S1112, the user apparatus sends control signaling to the base station to notify the base station that the handover to the target small node device has been successfully performed.
In step S1113, some of the traffic data is transferred between the user equipment 100 and the server 600 via the D2UE connection 710 and the target small node device 500.
In step S1114, a portion of the traffic data is transferred between the user equipment 100 and the server 600 via the BS2UE connection 720 and the base station 200. Step S1114 is the same as step S1102. That is, steps (S1102 and S1114) may be continued during the steps described in FIG.
The process shown in FIG. 17 may be described as an operation of the source small node device 500 as follows. The operation of the source small node device 500 is to transfer a part of the data transferred between the user device 100 and the server 600 using the D2UE connection 710 (step S1101) and the user device to the target small node device. This includes receiving a control signaling that notifies the source small node device 500 that it should be handed down, and terminating the D2UE connection 710 with the user apparatus 100 (step S1109).
The process shown in FIG. 17 may be described as an operation of the target small node device 500 as follows. The operations of the target subnode device 500 include receiving the control signaling in preparation for the handover transmitted by the base station (step S1106), transmitting the response to the control signaling (step S1107), and the user equipment and the target subnode device. Receiving the control signaling to establish a connection with (step S1110), sending the response to the control signaling (step S1111), and the data transferred between the user device and the server using the D2UE connection 710. Includes a partial transfer of (step S1113).
The process shown in FIG. 17 may be described as an operation of the user apparatus 100 as follows. The operation of the user device is performed by transferring a part of the data transferred between the user device and the server 600 using the D2UE connection 710 with the source small node device (step S1101) and using the BS2UE connection 720. Transfer of a part of the data transferred between the user device and the server 600 (step S1102), measurement of the D2UE connection (step S1103), transmission of the measurement report to the base station (step S1104), and Reception of control signaling (step S1108) instructing the user device to take a handover to the target small node device, transmission of control signaling to establish a connection between the user device and the target small node device (step S1110), and control. Receiving a response to the signaling (step S1111), transmitting control signaling to the base station to notify the base station that the handover to the target small node device was successful (step S1112), and the target small node device. Partial transfer of data transferred between the user equipment and server 600 using the D2UE connection 710 (step S1113) and transfer between the user equipment and server 600 using the BS2UE connection 720. Includes the transfer of some of the data to be done (step S1114). Note that step S1102 is the same as step S1114, and this step may be continuously executed during all steps.
The process shown in FIG. 17 may be described as an operation of the base station 200 as follows. The operation of the base station is to transfer a part of the data transferred between the user device and the server 600 using the BS2UE connection 720 (step S1002) and to receive the measurement report transmitted by the user device 100 (step S1002). Step S1104), the determination that the user device should hand over to the target small node device (step S1105), the transmission of control signaling to the target small node device in preparation for the handover (step S1106), and Receiving a response to the control signaling (step S1107), sending the control signaling to the user device (step S1108) instructing the user device to perform a handover to the target small node device, and the user device to the target small node device. Control to notify the source small node device that a handover should be performed Control to notify the base station that the transmission of signaling to the source small node device (step S1109) and the execution of the handover to the target small node device have been successful. It includes receiving the signaling (step S1112) and transferring a portion of the data transferred between the user equipment and the server 600 using the BS2UE connection 720 (step S1114).
The operation of the base station 200 according to the embodiment will be described with reference to FIG. The control method shown in FIG. 18 is an example of radio resource control or call reception control of the D2UE connection 710. In step S1201, the base station determines whether the number of user devices using the D2UE connection 710 is greater than a predetermined threshold. Alternatively, the base station determines the degree of congestion that can be determined based on at least one of the number of active user devices, the number of D2UE connections, the amount of traffic data, the interference level in the frequency band in which D2UE communication operates, and so on. It is determined whether or not the degree of congestion is greater than a predetermined threshold value. In other words, in step S1201, the base station can determine whether the cell is heavily congested.
If the number of user devices is not greater than a predetermined threshold (step S1201: NO), in step S1202, the base station allows the configuration of a new D2UE connection between the small node device and the user device. More specifically, when traffic data is generated as in step S801 and the user equipment attempts to set up a new BS2UE connection with the base station and a new D2UE connection with the small node device, the base station is the base station. Allows new D2UE connection settings with small node devices in addition to new BS2UE connection settings with. Alternatively, if the user equipment has a BS2UE connection with the base station and the user equipment attempts to set up a new D2UE connection with the small node device, the base station may allow the new D2UE connection with the small node device. Good.
If the number of user devices is greater than a predetermined threshold (step S1201: YES), in step S1203, the base station does not allow the setting of a new D2UE connection between the small node device and the user device. More specifically, when traffic data is generated as in step S801 and the user equipment attempts to set up a new BS2UE connection with the base station and a new D2UE connection with the small node device, the base station is the small node device. Do not allow the setting of new D2UE connections with. Here, the base station may allow the setting of a new BS2UE connection with the base station and not only the new D2UE connection with the small node device. Alternatively, if the user equipment has a BS2UE connection with the base station and the user equipment attempts to set up a new D2UE connection with the small node device, the base station may not allow the new D2UE connection with the small node device. It is possible.
In the above example, the small node device has one user device and one D2UE connection, but like a conventional base station, the small node device may have two or more user devices and two or more D2UE connections. It is possible. The radio resources of each D2UE connection may be shared among a plurality of user devices, or may be controlled by a base station or a small node device.
In the above example, the transmissions of the D2UE connection 710 and the BS2UE connection 720 can operate in different frequency bands, but in another embodiment the D2UE connection may operate simultaneously in the same band as the BS2UE connection. In this scenario, interference mitigation techniques can also be used to achieve coexistence of D2UE and BS2UE transmissions within the frequency band.
For example, since the D2UE connection 710 is configured by the base station, the base station knows that the user equipment will not respond to signaling from the base station using different frequencies / time slots. In such an embodiment, the D2UE connection 710 is provided with a transmit slot capable of BS2UE communication (from the base station to the user's device) to support continuous connection and management by the base station. It may be set. In other words, the user device can communicate with the base station at a predetermined on-time and communicate with the small node device at other times (off-time).
Alternatively, in another embodiment in which transmission by the D2UE connection 710 occurs simultaneously in the same bandwidth as base station transmission, OFDM resource elements (REs) of various resource blocks (RBs) are reserved for each link. In one embodiment, the RE used for control signaling is not used on the D2UE link and therefore remains empty for any D2UE link transmission. D2UE link transmissions are transmitted on other REs, including their own control signaling to the user equipment. In such an embodiment, the user apparatus can receive an RE, such as a control RE from a base station, at the same time as communication from the small node device. A base station is a radio resource that can cause transmission over a D2UE link to turn off transmission on a BS2UE link or reduce transmission power. The radio resource may be a time domain resource or a frequency domain resource.
In the above embodiment, the D2UE link is similar to a regular BS2UE link. Specifically, the small node device may transmit common pilot signals, broadcast signals, synchronization signals, physical layer control signaling, and the like. Alternatively, the D2UE link may transmit some signals and channels but not the rest. For example, the common pilot signal and the physical layer control signaling may be transmitted on the D2UE link, and other channels and signals such as broadcast channels / signals and synchronization signals may not be transmitted on the D2UE link. Alternatively, the common pilot signal may be transmitted over the D2UE link and other channels and signals such as physical layer control signaling, broadcast channel / signal, synchronization signal, etc. may not be transmitted over the D2UE link. Alternatively, only frequently transmitted pilot or sync signals are transmitted over the D2UE link, and other channels and signals such as common pilot signals, physical layer control signaling, broadcast channels / signals, conventional sync signals are not transmitted over the D2UE link. You may do so.
Alternatively, the D2UE link may be a device-to-device (D2D) link. In such a scenario, most of the common signals / channels such as common pilot signals, broadcast signals, synchronization signals, and physical layer control signaling may be omitted on the D2UE link, and only the channels that transfer data may be transmitted on the D2UE link. .. Alternatively, even in this scenario, some of the channels / signals, such as infrequently transmitted pilot or synchronization signals or physical layer control signaling, may be transmitted over the D2UE link.
Whether the D2UE link resembles a regular BS2UE link or a D2D link, the D2UE link may be based on an LTE-type wireless interface or the interface of another system. For example, the D2UE link may be based on WCDMA®, CDMA2000, WiFi, WiMAX, LTE-Aadvanced, TD-SCDMA, or TD-LTE.
For example, the D2UE connection 710 may be configured based on a WiFi-type wireless interface. For such use, the WiFi access point can be considered as a small node device 500. In particular, the D2UE communication unit 504 of the small node device 500 communicates with the user device 100 using the WiFi wireless interface, while the wireless resource control of the WiFi wireless interface is performed by the base station 200. The control signaling of radio resource control may be transmitted by BS2UE connection 720 and BS2D connection 730.
In a mobile communication system, it is necessary to maintain the connectivity of mobile communication even when a mobile station (user device) moves from cell to cell, so mobility such as cell identification, measurement, handover, cell selection / reselection, etc. The process is extremely important. When the mobile station frequently detects and measures adjacent cells, the connectivity is improved, but the battery consumption is increased, which lowers the quality of service in the mobile communication system. In such cases, the mobile station needs to minimize battery consumption due to the mobile process while at the same time obtaining high quality mobile performance.
Further, the mobile process is extremely important from the viewpoint of interference in the mobile communication system. In particular, it is extremely important for the mobile station to communicate with the base station having the highest wireless link quality. Radio link quality corresponds to at least one of path loss, pilot signal received power, signal-to-interference ratio, and so on. If the mobile station does not communicate with the highest link quality base station, as if the mobile station communicates with the second highest quality base station, then the mobile station's, as illustrated in Figures 19A and 19B. Since the transmission power is too high for other wireless links, it causes interference with other communications.
In Figure 19A, mobile station # A1 communicates with the second highest radio link quality base station instead of the highest radio link quality base station. As a result, the signal transmitted by mobile station # A1 interferes with communication between the base station with the highest wireless link quality and other mobile stations. However, in FIG. 19B, since mobile station # A1 communicates with the base station having the highest wireless link quality, the signal transmitted from mobile station # A1 does not interfere with other communications.
This interference is intra-frequency interference or inter-frequency interference. In the case of inter-frequency interference, adjacent channel interference on the transmitter side or receiver block characteristics on the receiver side may degrade the quality of other communications. The problem of interference may be addressed not only in the mobility process but also in other radio resource management processes. In short, the mobile process and other wireless resource management processes are suitable in mobile communication systems to achieve good quality connectivity, longer battery life of mobile stations, reduced interference in the system, etc. It should be done.
Moreover, in addition to the interference problems mentioned above, pilot contamination problems may occur. When a pilot signal transmitted from one cell collides with a pilot signal transmitted from another cell, the colliding pilot signals interfere with each other unless they are orthogonal to each other. When the user device needs to measure multiple cells with strong received signal power at the receiver of the user device, the signal-to-interference ratio (SIR) of each cell deteriorates due to interference, and the cell search / measurement accuracy deteriorates. To do. It should be noted that cell search and measurement for a low SIR cell requires higher power consumption than a high SIR cell because the cell search and measurement require a longer time.
In the hybrid D2UE and BS2UE systems shown above, such mobility and radio resource management steps are performed on the D2UE link in addition to the BS2UE link. It should be noted that due to the small cell size in the D2UE link, mobility performance is more likely to deteriorate and interference problems can occur more often. Therefore, the above mobility process and other radio resource management processes are extremely important for D2UE links. The mobility process and other radio resource management processes in the D2UE link will be described in more detail below.
In the following example, it is assumed that the carrier frequency of the D2UE connection 710 is 3.5 GHz and the carrier frequency of the BS2UE connection between the base station and the user device is 2 GHz, as in the above example. Note that the frequency band is merely an example, and different frequency bands can be applied in another embodiment.
FIG. 20 illustrates a wireless communication system in one embodiment. This is basically the same as in FIG. 1, but with some modifications compared to FIG. 1 to illustrate the mobility process and wireless resource management of the wireless communication system. Figure 20 shows three small node devices (500A, 500B, 500C) for illustration purposes.
The operation of the mobile communication system according to the embodiment of the present invention will be described with reference to FIG. The operation involves establishing a connection on the D2UE connection 710. The operation corresponds to the details of steps S803 and S804 of FIG. 14 or steps A803a, A803b, A803c, A804a, A804b, A804c, A804d, A804e, and A804f of FIG. 14A.
In step S1301, base station 200 transmits control signaling for D2UE connection 710 to user equipment 100. Control signaling is transmitted in step A803 of Figure 14A instead of S1301. Alternatively, the control signaling may be transmitted to the user apparatus 100 as a part of the broadcast information. The control signaling includes at least one of frequency resource information of the D2UE pilot signal, time resource information of the D2UE pilot signal, and code resource information of the D2UE pilot signal. An example of the D2UE pilot signal will be further described below.
The control signaling can include information on the transmit power of the D2UE pilot signal. That is, the transmission power of the D2UE pilot signal may be transmitted as one of the information elements of the control signaling. Further, the control signaling may include information about the measurement operation in the user apparatus 100.
In step S1302, the small node device sends a D2UE pilot signal with a given radio resource. More specifically, the small node devices 500A, 500B, and 500C transmit the D2UE pilot signal with a given radio resource. The radio resource consists of at least one of a time resource, a code resource, and a frequency resource. Information on a given radio resource may be signaled by the control signaling described in step S1301. In this sense, the "predetermined radio resource" corresponds to the radio resource indicated by the base station.
<D2UE pilot signal> FIG. 22 shows an example of the radio resource of the D2UE pilot signal. In FIG. 22, frequency resource # 3 is allocated as a frequency radio resource and time resource # 6 is allocated as a time radio resource. In addition, each small node device receives its own code resource. For example, code resources # 0, # 1, and # 2 are assigned to small node devices 500A, 500B, and 500C, respectively. The code resource may be a combination of the CAZAC series (or Zadoff-Chu series) and the cyclic shift as shown below.
Assume that time synchronization is available for all D2UE connections. Specifically, the time slots of all D2UE connections are aligned with each other. For each small node device 500, time synchronization may be obtained using GPS. Alternatively, time synchronization may be obtained by BS2D connection. That is, time frame synchronization of the D2UE connection may be obtained based on the signal transmitted by the base station so that the D2UE connections are synchronized with each other. Other time synchronization techniques may be used to synchronize the D2UE connection. In either case, the time frame timing of the D2UE connection is specified so that the D2UE connections are synchronized with each other in time.
For the user apparatus 100, time synchronization is obtained by the BS2UE connection 720 using the signal transmitted by the base station 200 so that the time frame timing of each D2UE connection is aligned with the remaining D2UE connections. Other time synchronization techniques may be used to obtain time synchronization of the D2UE connection. As a result, for both the small node device 500 and the user device 100, the time frame timing of each D2UE connection obtains time synchronization with the remaining D2UE connections.
Time synchronization will be further described below. For example, as illustrated in FIG. 22A, the D2UE link time slot is perfectly aligned with the BS2UE connection time slot. Alternatively, as shown in FIG. 22B, a time offset may be provided between the D2UE connection time slot and the BS2UE connection time slot.
More specifically, as shown in FIGS. 22C and 22D, each time offset between the D2UE connection time slot and the BS2UE connection time slot corresponds to the area supported by each base station 200 (base station). ) It may be specified for each coverage area. Figure 22C illustrates two macro (base station) coverage areas # A and # B, with multiple small node devices in place. FIG. 22D illustrates the relationship between the BSUE connection and the D2UE connection of FIG. 22C on the time axis. In FIG. 22D, the time offset #A is specified for the macro (base station) #A coverage area and the time offset #B is specified for the macro (base station) #B coverage area. You can also specify each time offset so that all D2UE connections are in sync. The base station 200 may notify the user apparatus 100 of the time offset value (time offset #A or time offset #B in FIG. 22D) as part of the control signaling. Further, the base station 200 may notify the small node device 500 of the time offset value (time offset #A or time offset #B in FIG. 22D) as part of the control signaling. The time offset value may be included in the control signaling in step S1301 of FIG. As a result, even if there is no time synchronization of the macro (base station) network, that is, if macro # A and macro # B are not aligned in time, as illustrated in FIG. 22D. The D2UE connection in the macro #A coverage area can be aligned with the D2UE connection in the macro #B coverage area.
For the user device 100, the user device decodes the D2UE pilot signal transmitted by the plurality of small node devices with predetermined radio resources (frequency resource # 3 and time resource # 6) to minimize power consumption. A more specific example is shown below. Since the time synchronization by BS2UE has already been obtained as described above, the user device 100 consumes the battery to perform time synchronization with multiple small node devices (like the conventional time synchronization using LTE PSS / SSS). You don't have to get it. In this way, the complexity of cell identification is reduced and the power consumption for cell identification is reduced.
<UE operation for receiving D2UE pilot signal> As shown in FIG. 22E, the small node devices 500A, 500B, 500C, and 500D transmit the D2UE pilot signal to the user device 100. As mentioned above, the D2UE pilot signals have common time domain and frequency domain resources, but each D2UE pilot signal has its own code domain resources. For example, code resources # 0, # 1, # 2, and # 3 may be assigned to the small node devices 500A, 500B, 500C, and 500D, respectively. In one embodiment, Constant Amplitude Zero Auto Correlation (CAZAC) series can also be used for the code. More specifically, the Zadoff-Chu sequence can be used as a code resource. Alternatively, the Walsh series may be used as a code. In the orthogonal code embodiment, the code sequence from one small node device is orthogonal to the sequence used for the neighboring small node device. In addition, partially orthogonal code sequences may be used for small node devices. In such an embodiment, some code sequence pairs are orthogonal to each other and others are not.
Walsh-Hadamard sequences do not interfere with each other. As a result, even when D2UE pilot signals transmitted from a plurality of small node devices collide with each other, the problem of so-called pilot contamination can be avoided. In addition, the SIR of the D2UE pilot signal can be improved by avoiding the problem of pilot contamination, thus reducing power consumption for cell search and measurement.
Each pilot signal may have a physical layer format as shown in FIG. 22F. This physical layer format may include cyclic prefixes, sequence parts, and guard intervals. The guard section is the same as the blank part. The CAZAC series may be applied to the series part. In such an embodiment, the user apparatus 100 has a receive window as shown in FIG. 22G and only needs to decode each D2UE pilot signal transmitted by each small node device in one or more attempts. The user apparatus 100 acquires the delay profile of each D2UE pilot signal as shown in FIG. 22H, and the delay profile of each D2UE pilot signal is shifted by the cyclic shift of the Zadoff-Chu series. In Fig. 22H, it is assumed that the cyclic shift of the small node device 500A is zero. As a result, the user device 100 can easily measure the delay and received power level of the D2UE pilot signal for each small node device. In this way, UE complexity in cell search and measurement can be reduced.
It is also possible to adjust the cyclic shift based on the cell range of each small node device 500. Alternatively, the patrol shift may be adjusted based on the cell range of base station 200. When the cell range is large, the time difference between the D2UE pilot signals is also large, so it is necessary to set a large cyclic shift. On the other hand, when the cell range is small, the cyclic shift is also small. The base station 200 may notify the user apparatus 100 of the cyclic shift setting for each small node device by using control signaling. More specifically, the cyclic shift information can be included in the control signaling in step S1301 of FIG. Similarly, the base station 200 may notify the small node device 500 of its cyclic shift setting using control signaling.
In yet another embodiment, a physical random access channel (PRACH) or a physical channel similar to PRACH may be used for the D2UE pilot signal. PRACH is specified in TS36.211 as an LTE physical channel. In this way, each small node device 500 transmits a signal similar to a random access preamble with a predetermined radio resource. Base station 200 assigns each small node device its own unique random access preamble. Radio resources for signals may be allocated by base station 200.
As described above, the D2UE pilot signal may be transmitted infrequently. For example, the D2UE pilot signal may be transmitted once per second. Time synchronization is obtained using a BS2UE connection, so there is no need to send D2UE pilot signals frequently. As a result, the user equipment only needs to decode the D2UE pilot signal once per second, minimizing the power consumption for the resulting pilot signal measurement. In addition, the D2UE pilot signal is transmitted much less frequently than the LTE common reference or sync signal, unlike the traditional LTE femto / pico base station instead of a small node device. Interference from the signal is not a problem. The period of the D2UE pilot signal may be very large, for example 1 second or 2 seconds, or moderately large, such as 100 ms or 200 ms. In very large cycle embodiments, the power consumption and interference problems of the measurements can be significantly reduced, but multiple measurement samples are required for high accuracy, so the user equipment 100 is an adjacent extension. Further time is required to detect the user device and measure these. As a result, delays in the mobility process can be increased. On the contrary, when the period is moderately large, the problem of power consumption and interference of measurement is reduced to some extent, but the delay time is reduced. Therefore, the period of the D2UE pilot signal can be optimized based on the above aspects such as power consumption of measurement, interference problem, delay time of mobile process and so on. The cycle of the D2UE pilot signal can be set by the network, and the base station 200 may notify the user device 100 of the cycle by using the control signal. For example, the control signaling in step S1301 of FIG. 21 can be used in this way. Similarly, the base station 200 may use the control signal to notify the small node device 500 of the cycle.
If the user device does not support multiple radio frequency components and the first frequency carrier is used for the BS2UE connection 720 and the second frequency carrier is used for the D2UE connection 710 at the same time, the user device measures the D2UE connection 710. As can be done, the user equipment may stop transmitting and receiving the signal on the BS2UE connection 720 while the D2UE pilot signal is being transmitted. In this case, the base station may take such operation of the user equipment into account for scheduling the BS2UE connection 720. That is, the base station may avoid allocating radio resources to the user equipment while the D2UE pilot signal is being transmitted.
The D2UE pilot signal is also referred to as a "D2UE sounding reference signal" or a "D2UE synchronization signal". The D2UE pilot signal may be dispersed in the frequency domain to suppress fluctuations in signal strength due to Rayleigh fading, enabling more accurate measurement of radio link quality. The base station may notify the user equipment of the D2UE pilot signal information of each small node device. This information may be included in the control signaling in step S1301 of FIG. Examples of pilot signal information include:
-D2UE Pilot signal code region resource -For example, Zadoff-Chu series index -D2UE pilot signal frequency domain resource -D2UE pilot signal time domain resource -Time offset between D2UE and BS2UE connections -D2UE Pilot signal transmission power -D2UE pilot signal patrol shift information
The above information may be specified for each small node device and may therefore be included in the adjacent small node device list for each small node device. The above information may be signaled by broadcast information in a BS2UE connection, or individual signaling may be performed in a BS2UE connection. In the above example, a single time domain resource and a single frequency domain resource are specified as shown in FIG. However, it is also possible to configure two or more time domain or frequency domain resources on a small node device. For example, if a cell contains a relatively large number of small node devices, the code domain resources may not be sufficient and two or more time domain resources or frequency domain resources may be required.
With reference to FIG. 21 again, in step S1303, the user apparatus 100 receives the D2UE pilot signal and measures the D2UE pilot signal with a predetermined radio resource. The user device decodes the D2UE pilot signal transmitted by the plurality of small node devices 500 and measures the plurality of small node devices. More specifically, the user device acquires the radio link quality of the D2UE connection between the user device and a plurality of small node devices. Radio link quality includes at least one of path loss, received power of the D2UE pilot signal, SIR of the D2UE pilot signal, received quality of the D2UE pilot signal, and so on. The user device can detect the small node device with the highest wireless link quality based on the measurement. The path loss may be obtained from the received power of the D2UE pilot signal and the transmitted power of the D2UE pilot signal included in the control signaling in step S1301. The reception quality of the D2UE pilot signal may be the ratio of the received power of the D2UE pilot signal to the total received signal strength.
At step S1304, the user device sends a measurement report to the base station. The measurement report includes the measurement results obtained in step S1303. More specifically, the measurement report may include the ID of the small node device with the highest wireless link quality. In other words, User Equipment 100 may recognize the best small node device based on the radio link quality of the D2UE connection in step S1304. In this way, the information of the small node device can include the identification number of the small node device and the radio link quality of the small node device.
In addition, the measurement report may include information on adjacent small node devices that do not have the highest wireless link quality. That is, the measurement report may include information on adjacent small node devices with the second or third highest radio link quality. In another embodiment, the subnode device information may include even lower radiolink quality, such as information for an adjacent subnode device with the fourth highest or lower radiolink quality. The base station may indicate in step S1301 how many small node device information is included in the measurement report. Alternatively, the measurement report may include all small node devices with radio link quality above the threshold. The base station may indicate the desired threshold in step S1301. In yet another embodiment, the measurement report may include information about all small node devices whose radio link quality is below the threshold (which may be indicated by base station 200 in step S1301).
At step S1305, the base station establishes a D2UE connection 710. More specifically, the base station establishes a wireless link between the user equipment and the small node device with the highest wireless link quality notified in step S1304. In addition to this, in step S1305 the base station allocates radio resources to the D2UE connection 710. The radio resource is at least one of a frequency domain resource, a time domain resource, a code domain resource, and the like. More specifically, the radio resource may be the carrier frequency of the D2UE connection 710. For example, base station 200 may select a radio resource that is not used in the small node device with the second or third highest radio link quality reported in step S1304. As a result, it is possible to avoid interference with other D2UE connections in the adjacent small node device. Alternatively, the base station may allocate unused radio resources to the other small node device 500 located in the vicinity of the small node device with the highest radio link quality. The base station may have the location information of the small node device 500. In the embodiment shown in FIG. 21, the power consumption of the measurement can be reduced. Further, the reduction of interference can be realized.
The operation of the mobile communication system according to the embodiment will be described with reference to FIG. 23. The operation concerns establishing a connection with D2UE connection 710. The operation corresponds to step S804 of FIG. 14 or steps A803a, A803b, A803c, A804a, A804b, A804c, A804d, A804e, and A804f of FIG. 14A. Since steps S1401 to S1404 in FIG. 23 are the same as steps S1301 to S1304 in FIG. 21, the description of steps S1401 to S1404 will be omitted.
In step S1405, base station 200 determines if the path loss is less than the threshold. More specifically, the base station 200 determines whether or not the path loss of the small node device having the highest wireless link quality is smaller than the threshold value. If the path loss of the small node device with the highest wireless link quality is less than the threshold (step S1405: YES), base station 200 establishes a D2UE connection 710 in step S1406. In step S1406, as described in connection with step S1305, the base station allocates radio resources to the D2UE connection 710 in addition to establishing radio resources.
If the pathro of the base station with the highest wireless link quality is not less than the threshold (step S1405: NO), base station 200 does not establish a D2UE connection 710 in step S1407. In particular, since the base station 200 does not instruct the user device and the small node device to establish the D2UE connection 710, the user device communicates with the server 600 only by the BS2UE connection. Due to the high path loss and high transmission power required, the resulting D2UE connection can interfere with other D2UE connections or communications. The problem of such interference can be mitigated by using the control shown in FIG.
Although path loss is used in the determination in step S1405, other radio link quality indicators such as the received power of the D2UE pilot signal, the reception quality of the D2UE pilot signal, and the SIR of the D2UE pilot signal may be used. In this case, if the radio link quality is better than the threshold, the determination in step S1405 is "YES". Alternatively, the determination in step S1405 is "NO".
In addition to using the path loss of the small node device with the highest wireless link quality, the decision in step S1405 may be made based on the path loss of the adjacent small node device with the second or third highest wireless link quality. More specifically, the difference between the highest radio link quality and the second highest radio link quality can also be used to make decisions in step S1405. If the difference is greater than the threshold, base station 200 can allocate radio resources to the D2UE connection 710 (S1406). On the other hand, if the difference is not greater than the threshold, base station 200 does not allocate radio resources to D2UE connection 710 (S1407). If the difference is small, the D2UE connection can interfere with other connections. Therefore, the problem of such interference can be alleviated by utilizing the above control. This control is applicable to embodiments where the second or third highest radio link quality small node device in the radio resource has a D2UE connection with another user device.
The operation of the mobile communication system according to the embodiment will be described with reference to FIG. 24. The operation is related to mobility control on the D2UE connection 710. The operation corresponds to steps S1103 to S1112 in FIG.
Steps S1501 to S1503 are similar to steps S1301 to S1303 in FIG. The only difference is that steps S1301 through S1303 are executed before the D2UE connection is established, while steps S1501 through S1503 are executed after the D2UE connection is established. Even if a D2UE connection is established, the user device needs to make measurements on known or unknown adjacent cells. In this sense, the measurements in steps S1301 to S1303 are equal to steps S1501 to S1503. Therefore, the description of steps S1501 to S1503 will be omitted.
In step S1504, user device 100 determines if there is an adjacent small node device closer to user device 100 than the serving small node device. As shown above, the serving small node device refers to the small node device currently communicating with the user device 100. More specifically, if the adjacent small node device has a higher radio link quality than the serving small node device, the decision in step S1504 is considered "YES".
Hysteresis may be taken into account in the determination of step S1505. More specifically, the judgment in step S1404 is regarded as "YES" when the following equation holds.
(Wireless link quality of adjacent cell)> (Wireless link quality of serving cell) + Hyst Here, Hyst is hysteresis. For example, Hyst is 3 dB. In addition to this, hysteresis in the time domain may be used. Time domain hysteresis is also referred to as "trigger time".
If a closer adjacent small node device is detected (step S1504: YES), the user equipment sends a measurement report to the base station in step S1505. These measurement reports may include determination of closer adjacent small node devices.
In step S1506, the base station transmits a handover command to the user equipment. The base station sends control signaling to the small node device in preparation for the handover. Further, the base station may notify the serving small node device that the user device is handed over to the adjacent small node device.
In step S1507, the user device performs a handover to an adjacent small node device.
On the other hand, if no closer adjacent small node device is detected (step S1504: NO), in step S1508 the user device maintains a D2UE connection with the small node device.
The operation of the mobile communication system according to the embodiment will be described with reference to FIG. 25. This operation relates to mobility control in the D2UE connection 710. This operation is performed with the D2UE connection already established. Steps S1601 to S1603 are similar to steps S1301 to S1303 in FIG. The only difference is that steps S1301 through S1303 are executed before the D2UE connection is established, while steps S1601 through S1603 are executed after the D2UE connection is established. Therefore, the description of steps S1601 to S1603 will be omitted.
In step S1604, it is determined whether the path loss of the user device is larger than the threshold value. More specifically, the user apparatus determines whether the path loss of the serving small node device is larger than the threshold value. The base station notifies the user device of the threshold value by the control signaling in step S1601.
In steps S1602 and 1603, the user equipment measures path loss using the D2UE pilot signal, but other signals or channels may be used for path loss measurement. For example, the pilot signal for channel estimation or demodulation of the D2UE connection 710 may be used for path loss measurement. The pilot signal for channel estimation or demodulation allows for more accurate path loss measurements than the D2UE pilot signal used for mobility measurements. When calculating the path loss using another signal or channel, the transmission power information of the channel may be included in the other signal or channel. The user device can calculate the path loss based on the received power of another signal or channel, or the transmitted power of another signal or channel.
If the path loss of the serving small node device is greater than the threshold (step S1604: YES), the user equipment sends a measurement report to the base station in step S1605. The measurement report shows that the path loss of the small node device is larger than the threshold.
At step S1606, the base station releases the radio resources of the D2UE connection 710. More specifically, base station 200 sends a control message to release the D2UE connection 710. As a result, the D2UE connection 710 is released.
If the path loss of the serving small node device is not greater than the threshold (step S1604: NO), user device 100 maintains a D2UE connection with the small node device 500 in step S1607.
In the above example, a value indicating the wireless link quality may be used in addition to the path loss. For example, at least one of the received power of the pilot signal, the SIR of the pilot signal, the reception quality of the pilot signal, and the like can be used. In this case, if the radio link quality is lower than the threshold, the decision in step S1604 is "YES" or the decision in step S1604 is "NO". Based on the radio resource management described in Figure 25, interfering D2UE connections can also be eliminated for good system quality.
In another embodiment, some of the traditional BS2UE operations may be omitted in the D2UE connection 710. More specifically, at least one of the operations shown below may be omitted.
-Transmission of notification channel in DL -Transmission of common reference signal in DL -Transmission of primary sync signal / secondary sync signal in DL -Sending paging signal on DL -Send individual RRC signaling related to RRC processes such as establishing a connection, reestablishing a connection, setting up a connection, reconfiguring a connection, releasing a connection, etc. -Transmit control signaling for handovers such as measurement configuration, measurement control, handover commands, handover complete, etc.
In addition, other conventional BS2UE operations may be supported in the D2UE connection 710 according to another embodiment. More specifically, it can support at least one of the following operations:
-Send PDCCH on DL -Transmit PHICH on DL -Send PCFICH on DL -Send PUCCH on UL -Send PUSCH on UL -Send PRACH on UL -Uplink power control -DL power control -Adaptive modulation and coding for DL and UL -DRX -HARQ
<Traffic measurement> In mobile communication systems, it is extremely important to collect measurement results of wireless interfaces. The measurement results can be used for parameter optimization, determination of whether additional base stations should be set, and handoff to additional base stations or additional carriers. Optimization of this parameter is also commonly referred to as network optimization. In addition, the measurement results are also available on the Self-Organized Network (SON). The measurement result may be supplied to the SON entity, and the SON entity may change some of the parameters based on the measurement result. In general, as the number of nodes increases, so does the complexity and cost of such measurements. Therefore, when a network operator uses many small nodes such as a pico base station or a femto base station, how to efficiently collect measurement results becomes a difficult problem.
In the present disclosure, the addition of small node devices raises such measurement problems. Since the number of small node devices is larger than that of existing base stations, more efficient measurement process and network optimization are required. The measurement process is as described below.
FIG. 26 illustrates an example of a communication system. Compared to the system described with reference to FIG. 2, the system of FIG. 26 is similar except that the D2UE measurement data acquisition unit 208 of the base station 200 is added.
The D2UE measurement data collection unit 208 is configured to collect the measurement data of the D2UE link. Although the D2UE measurement data acquisition unit 208 is shown to be located outside the base station 200 in FIG. 26, it may be located inside the base station 200 or may be integrated with the base station 200. Alternatively, the D2UE measurement data acquisition unit 208 may be located in another node such as an access gateway 300 or a node in the core network 400. There are at least two types of measurement data in the system of FIG. One is the measurement data measured by the base station 200, and the other is the measurement data measured by the small node device 500. In the following, these two types of measurement data will be described separately.
<Measurement data measured by base station 200> FIG. 27 shows an example of the measurement performed by the base station 200. Since the D2UE communication control unit 204 controls the wireless link connection of the D2UE connection 710 as described above, in this embodiment, the D2UE communication control unit 204 performs the measurement shown in FIG. 27, whereby the measurement can be easily performed. .. The wireless link connection control includes at least one of establishment / configuration / reconfiguration / reestablishment / release of the D2UE connection 710. Further, the wireless link connection control includes handover of the D2UE connection 710 or troubleshooting of the wireless link.
The D2UE communication control unit 204 makes a measurement and transmits the measurement result to the D2UE measurement data acquisition unit 208. Measurement index # 0 corresponds to the number of D2UE connections. The number of D2UE connections is the total number of D2UE connections in the macro cell coverage area in which the base station 200 provides the wireless communication service to the user device 100. Alternatively, the number of D2UE connections may be equal to the D2UE connections of the small node device. From this measurement item, the network operator can detect how many D2UE connections are used in the macro coverage area or each small node device. Such information can be used by network operators to determine if a new small node device should be installed. If the number of D2UE connections in the small node device 500 is greater than the threshold, the network operator determines that a new small node device should be installed.
Alternatively, if the number of D2UE connections of the small node device 500 is greater than the threshold, the network operator determines that the radio resources of the small node device should be increased. Radio resources are frequency resources. For example, if the number of D2UE connections in the small node device 500 is greater than the threshold, the network operator determines that the frequency carriers of the D2UE connections handled by the small node device should be increased.
In addition to the number of D2UE connections, the number of logical channels in the D2UE connection may be measured as part of measurement item # 0. Alternatively, the number of D2UE connections may be measured for each logical channel. More specifically, the number of D2UE connections to which the logical channel supporting the best effort packet is forwarded may be measured.
Measurement index # 1 corresponds to the radio resource used in the D2UE connection. The radio resources of the D2UE connection correspond to all the radio resources of the D2UE connection in the macro cell coverage area. Alternatively, the radio resource corresponds to the radio resource used in each small node device. This measurement item allows the network operator to detect how much radio resources are being used in the macro coverage area or the D2UE connection of each small node device. Such information can be used by network operators to determine if a new small node device should be installed. For example, if the amount of radio resources used by a small node device in a D2UE connection is greater than the threshold, the network operator can determine that a new small node device should be installed. Alternatively, if the amount of radio resources in the D2UE connection of the small node device is greater than the threshold, the network operator determines that the radio resources of the small node device should be increased.
Radio resources are frequency domain resources. For example, if the amount of radio resources of the small node device is larger than the threshold value, the network operator determines that the frequency carrier of the D2UE connection handled by the small node device should be increased. Alternatively, the radio resource is a time-frequency resource.
Radio resource measurement is performed separately for DL (small node device to user device) and UL (user device to small node device). Instead of the actual radio resource, the usage of the radio resource may be measured. The wireless resource usage (usage # 1) can be calculated as follows.
<maths num="1"><img id="000003" he="18" wi="140" file="JP2017099019A_D0001.tif" img-format="tif" img-content="drawing" /></maths>Where r (T) is the amount of radio resources allocated at time T, total_r (T) is the amount of radio resources available during time T, and T is the time at which the measurement is made. ..
Measurement index # 2 corresponds to the data rate in the D2UE connection. The data rate of the D2UE connection corresponds to the total data rate of the D2UE connection in the macro cell coverage area. Alternatively, the data rate of each small node device may be the data rate of the D2UE connection. This measurement item allows the network operator to detect how much data rate is available for the D2UE connection in the macro coverage area or each small node device.
The data rate can be calculated at the physical layer, MAC layer, RLC layer, or PDCP layer. In addition, the data rate may be calculated for each logical channel of the D2UE connection. The data rate may be calculated separately for the downlink (from the small node device to the user device) and the uplink (from the user device to the small node device). The status notification may be used in the calculation. For example, the actual data transmission is performed by the D2UE connection 710, but the status notification of the D2UE connection 710 can be transmitted to the base station 200 using the BS2UE connection 720 via the BS2UE communication unit 102 of the user device 100. Good. Figure 27A shows the transmission of the status notification from the user device 100 to the base station 200. Status notifications (including the status of each logical channel) may be transmitted in this way on both the D2UE connection 710 and the BS2UE connection 720. The status notification may include the status of each logical channel. As a result, the D2UE communication control unit 204 of the base station 200 can easily check how many bits are transmitted per second in the D2UE connection by using the status notification. The number of bits per second corresponds to the data rate of the D2UE connection 710. Alternatively, the D2UE communication control unit 204 may calculate the transfer data amount of the D2UE connection 710 by using the series number of the status notification. The change of the series number in one section corresponds to the amount of data transferred in that section.
In the above example, the user device 100 transmits a status notification to the base station 200. However, instead, the BS2D communication unit 502 of the small node device 500 may send a status notification to the base station 200 via the BS2D connection 730. The data rate corresponds to one D2UE connection in one small node device. Alternatively, the data rate may be the sum of the data rates of multiple D2UE connections in a single small node device. In yet another embodiment, the data rate may be the sum of the data rates of all D2UE connections within the macro coverage area. For example, the total data rate (Total_data_rate) of all D2UE connections is calculated according to the following formula.
<maths num="2"><img id="000004" he="18" wi="140" file="JP2017099019A_D0001.tif" img-format="tif" img-content="drawing" /></maths>Where data_rate is the data rate of one D2UE connection, n is the index of the D2UE connection, and N is the total number of D2UE connections. The network operator can use such information in determining whether a new small node device should be installed for similar data rate measurements reported by the user equipment, as described above.
Measurement index # 3 in Figure 27 corresponds to the success rate of establishing a D2UE connection. The success rate of D2UE connection establishment (Rate # 3) can be defined as follows.
<maths num="3"><img id="000005" he="18" wi="140" file="JP2017099019A_D0001.tif" img-format="tif" img-content="drawing" /></maths>Where N1 is the number of D2UE connections that have been successfully established and N2 is the number of D2UE connections that have failed to be established. The success rate of establishing a D2UE connection is that of all D2UE connections in the macrocell coverage area. Alternatively, the success rate of establishing a D2UE connection may be determined for each small node device. The failure rate of D2UE connection establishment may be measured instead of the success rate of D2UE connection establishment. The failure rate of D2UE connection establishment can be defined as follows.
(Failure rate of D2UE connection establishment) = 1- (Success rate of D2UE connection establishment)
From the success (or failure) of establishing a D2UE connection, the network operator decides whether to change some wireless interface parameters. For example, if the success rate is below the threshold, the network operator will ask for a change in the radio interface parameters.
The measurement index # 4 is the handover success rate of the D2UE connection. The handover success rate (Rate # 4) can be defined as follows.
<maths num="4"><img id="000006" he="18" wi="140" file="JP2017099019A_D0001.tif" img-format="tif" img-content="drawing" /></maths>Where N3 is the number of successful D2UE connection handovers and N4 is the number of unsuccessful D2UE connection handovers. The handover success rate is for all D2UE connections in the macrocell coverage area. Alternatively, the success rate of D2UE handover of individual small node devices may be measured. In yet another embodiment, the handover failure rate in the D2UE connection may be measured instead of the success rate. The handover failure rate of the D2UE connection can be defined as follows.
(D2UE connection handover failure rate) = 1- (D2UE connection handover success rate)
Based on the measurement item of success (or failure) of this handover, the network operator determines whether the handover parameter should be changed. For example, if the handover success rate is lower than the threshold, the network operator will ask for a change in the wireless interface parameters.
Measurement index # 5 corresponds to the success rate of reestablishing the D2UE connection. The success rate of reestablishment of connection (Rate # 5) in D2UE connection can be defined as follows.
<maths num="5"><img id="000007" he="18" wi="140" file="JP2017099019A_D0001.tif" img-format="tif" img-content="drawing" /></maths>Where N5 is the number of successful D2UE connection reestablishments and N6 is the number of unsuccessful D2UE connection reestablishments. The success rate of D2UE connection reestablishment is for all D2UE connections in the macrocell coverage area. Alternatively, the success rate may correspond to an individual D2UE connection. Alternatively, the failure rate of reestablishment of D2UE connection may be measured instead of the success rate of reestablishment of connection in D2UE connection. The failure rate of connection reestablishment in D2UE connection can be defined as follows.
(Failure rate of reestablishment of D2UE connection) = 1- (Success rate of reestablishment of D2UE connection)
Based on this measurement, the network operator decides whether to change some of the D2UE connection reestablishment parameters. For example, if the success rate of D2UE connection reestablishment is lower than the threshold, the network operator determines that some of the D2UE connection reestablishment parameters should be changed.
Measurement index # 6 corresponds to the number of D2UE connection handovers in the D2UE connection. This number may be for all D2UE connections in the macrocell coverage area. Alternatively, it may be the number of handovers for the D2UE connection of the small node device. From this measurement item, the network operator can determine whether to change the D2UE connection handover parameter. For example, if the number of handovers in a D2UE connection is greater than the threshold (which suggests that there is some ping-pong problem in the handover), the network operator asks for a change in the handover parameters.
Measurement index # 7 corresponds to the number of wireless link failures in the D2UE connection. This number may be for all radio link failures in the macro cell coverage area. Alternatively, it may be the number of wireless link failures in the small node device. The number of wireless link failures is reported from user device 100 through BS2UE connection 720. Alternatively, the small node device 500 may report through the BS2D connection 730. The radio link failure report may be included in the control signaling in step S1301. From this measurement item, the network operator can determine whether to change some of the wireless interface parameters. For example, if the number of radio link failures in a D2UE connection is greater than the threshold (which suggests that there are non-optimized radio interface parameters), the network operator should change some of the radio interface parameters. It can be judged that there is.
Finally, measurement index # 8 in Figure 27 corresponds to the number of reestablished D2UE connections. This number may be for all D2UE connections in the macrocell coverage area. Alternatively, this number may be the number of D2UE connection reestablishments in each small node device. Using this measurement item, the network operator can determine whether some of the wireless interface parameters should be changed. For example, if the number of connection re-establishments in a D2UE connection is greater than the threshold (which suggests that there are non-optimized radio interface parameters), the network operator should change some radio interface parameters. Can be judged.
<Measurement data of small node device 500> FIG. 28 shows an example of measurement items measured in the small node device 500. While the D2UE communication unit 504 (Fig. 11) makes the measurements listed in FIG. 28, the BS2D communication unit 502 sends the measurement results to the base station via the BS2D connection 730. The measurement result can also be sent to the base station 200 as part of the control signaling. The measurement result is transferred to the D2UE measurement data acquisition unit 208. In this way, the D2UE measurement data collection unit 208 can easily acquire the measurement result of the D2UE connection by utilizing the BS2D connection 730 which makes the collection of the measurement result very efficient.
The measurement index # A0 in FIG. 28 corresponds to the central processing unit (CPU) utilization of the small node device 500. CPU utilization can be used to determine if a small node device is relatively congested. For example, if the CPU utilization is higher than the threshold, the network operator decides that a new small node device should be installed.
Measurement index # A1 corresponds to the memory usage of the small node device 500. Memory usage can also be used to determine if a small node device is relatively congested. For example, if the memory usage is higher than the threshold, the network operator determines that a new small node device or additional memory should be installed.
The measurement index # A2 corresponds to the buffer utilization of the buffer in the small node device 500 and is similar to the measurement index # A1. Buffer utilization can also be used to determine if congestion is relatively high on small node devices. For example, if the buffer utilization is higher than the threshold, the network operator determines that a new small node device or additional memory should be installed.
Measurement index # A3 is the baseband processing utilization in small node devices. Baseband utilization can be used to determine if congestion is relatively high in small node devices. Indexes A0 to A3 thus correspond to the processing load on the small node device.
Measurement index # A4 corresponds to the amount of radio resources in the D2UE connection. The radio resources are not those assigned to the D2UE connection by the base station 200, but correspond to those actually used for data transmission. In such cases, the wireless resources used correspond to the congestion level of the D2UE connection. The amount of radio resources used in the D2UE connection can be used to determine whether the congestion level of the small node device 500 is relatively high compared to the threshold value. If the threshold is exceeded, the network operator will ask for a new small node device. The measurement of the radio resources used may be performed separately for DL (small node device to user device) and UL (user device to small node device).
The measurement index # A5 corresponds to the backhaul usage rate in the small node device, and is for determining whether the degree of congestion at the backhaul link is relatively high compared to, for example, the threshold value. If the threshold is exceeded, the network operator determines that additional bandwidth should be provided for the backhaul link.
Measurement index # A6 corresponds to the data rate of the D2UE connection. The data rate can be calculated at the physical layer, MAC layer, RLC layer, or PDCP layer. The data rate may be calculated by setting an averaging interval at the time when the data to be transmitted exists in the transmission buffer. For example, if the data exists only in 300 milliseconds in the measurement interval of 500 milliseconds, the data rate is calculated by calculating the average only in the interval of 300 milliseconds and not using the remaining interval. Alternatively, the data rate may be calculated over the entire measurement interval regardless of the presence or absence of data to be transmitted in the transmission buffer. The data rate may be measured separately for DL (small node device to user device) and UL (user device to small node device). The data rate may be calculated for each logical channel of the D2UE connection.
The data rate in the D2UE connection can be used to determine if the small node device 500 is relatively congested. For example, the amount of data rate may be compared to the threshold. If the threshold is not exceeded, the network operator determines that the congestion is relatively high and a new small node device should be installed.
Measurement index # A7 corresponds to the communication section in the D2UE connection. In some embodiments, the radio resources for D2UE communication are allocated by the base station 200, but the radio resources are used only when there is data to be transmitted over the D2UE connection. In this way, the section of D2UE communication corresponds to the section in which data is actually transmitted. This section can be used to check the data traffic pattern, such as when checking whether the data is a burst.
Unlike index # A7, measurement index # A8 corresponds to the section where data communication is not performed with D2UE connection. This section can also be used to check the data traffic pattern.
Measurement index # A9 corresponds to path loss in D2UE connection. Path loss can be used to estimate the actual coverage area for which small node devices provide wireless communication services. The network operator may compare such information with the threshold value to determine whether a new small node device should be installed in the area. For the path loss measurement, the average value of the path loss of the D2UE connection handled by the small node device 500 may be used.
Measurement index # A10 corresponds to the wireless link quality in the D2UE connection. Wireless link quality can be used to estimate communication quality in the coverage area where small node devices provide wireless communication services. The network operator can use this information to determine if some radio interface parameters should be changed. For the wireless link quality, the average value of the wireless link quality of the D2UE connection handled by the small node device 500 may be used. The radio link quality is at least one of the signal-to-interference ratio of the D2UE connection and the channel quality index (CQI) of the D2UE connection. More specifically, if the radio link quality of the D2UE connection is below the threshold, the network operator determines that some radio interface parameters should be changed. The measurement of wireless link quality may be performed separately for DL (small node device to user device) and UL (user device to small node device).
Measurement index # A11 corresponds to the block error rate (BLER) of the D2UE connection. BLER can be used to estimate the communication quality in the coverage area of the small node device 500. The network operator can use such information to determine whether some of the wireless interface parameters should be changed. BLER is the average value of BLER for D2UE connection handled by the small node device 500. A bit error rate may be used instead of BLER. If the BLER of the D2UE connection is greater than the threshold, the network operator determines that some radio interface parameters should be changed. BLER may be measured separately for DL (small node device to user device) and UL (user device to small node device).
Measurement index # A12 corresponds to the received signal power of the D2UE connection. The received signal power is used to estimate the communication quality in the coverage area of the small node device. The network operator may use such information to determine whether some of the wireless interface parameters should be changed. As the received signal power, the average value of the received signal power of the D2UE connection handled by the small node device 500 may be used. If the received signal power of the D2UE connection is higher than the threshold, the network operator can determine that some radio interface parameters should be changed. The received signal power may be measured separately for DL (small node device to user device) and UL (user device to small node device). For DL, the user device may report the received signal power to the small node device.
Measurement index # A13 corresponds to the transmission signal power of the D2UE connection. The transmitted signal power is used to estimate the communication quality in the coverage area of the small node device to which the small node device 500 provides the wireless communication service. The network operator may use such information to determine whether some of the wireless interface parameters should be changed. As the transmission signal power, the average value of the transmission signal power of the D2UE connection handled by the small node device 500 may be used. The transmission signal power may be measured separately for DL (small node device to user device) and UL (user device to small node device). For UL, the user device may notify the small node device of the transmitted signal power. If the transmit signal power of the D2UE connection is higher than the threshold, the network operator can determine that some radio interface parameters should be changed.
Measurement index # A14 corresponds to the interference power of the D2UE connection. The interfering power is used to estimate the communication quality in the coverage area where the small node device 500 provides wireless communication services. The network operator may use such information to determine whether some of the wireless interface parameters should be changed. As the interference power, the average value of the interference power of the D2UE connection handled by the small node device 500 may be used. If the interference power of the D2UE connection is higher than the threshold, the network operator can determine that some radio interface parameters should be changed. Interference power may be measured separately for DL (small node device to user device) and UL (user device to small node device). For DL, the user device 100 may notify the small node device 500 of the interference power.
Measurement index # A15 corresponds to the location information of the small node device 500. The location information may be used for SON operations.
Measurement index # A16 corresponds to the number of user devices that have data to be transmitted in the transmit buffer. This number may be used to determine if the congestion level in the small node device 500 is relatively high. If the number of user devices with data to be transmitted is greater than the threshold, the network operator determines that the congestion is relatively high and a new small node device should be installed. The number of user devices in which data to be transmitted exists may be measured separately for DL (small node device to user device) and UL (user device to small node device). For UL, user equipment 100 may report to the small node device 500 whether the data to be transmitted exists in the transmit buffer. The number of user devices having data to be transmitted may be calculated for each logical channel of the D2UE connection. That is, the number of logical channels having data to be transmitted may be calculated. The user device in which the data to be transmitted exists may be regarded as an active user.
Measurement index # A17 corresponds to the number of user devices whose data rate is below the threshold. This number may be used to determine if the congestion level in the small node device 500 is relatively high. If the number of user devices with data rates below the threshold is less than another threshold, the network operator determines that the congestion is relatively high and a new small node device should be installed. The measurement of the number of user devices whose data rate is lower than the threshold value may be performed separately for DL (small node device to user device) and UL (user device to small node device). The number of user devices whose data rate is lower than the threshold value may be calculated for each logical channel of the D2UE connection.
Measurement index # A18 corresponds to the number of inactive user devices in the D2UE connection. In some embodiments, the radio resources for the D2UE connection are allocated by the base station, but the radio resources are used only when there is data to be transmitted. Therefore, there is a section where there is no data to be transmitted. The inactive user device corresponds to the user device that does not have the data to be transmitted over the D2UE connection.
Regardless of whether the user device or the small node device performs the traffic measurement, the D2UE measurement data collection unit 208 may use a part of the above measurement data for the call reception control of the D2UE connection. For example, if the number of D2UE connections of the small node device is larger than the threshold value, the D2UE measurement unit 208 determines that new D2UE connections should be prohibited. Other measurement items such as wireless resource usage may be used for call reception control instead of the number of D2UE connections. The D2UE communication control unit 204 may perform call reception control instead of the D2UE measurement data collection unit 208.
The operations of the base station, user equipment, and small node device described above may be realized by hardware or by software modules executed by a processor. Further, it can be realized by combining both of them.
Software modules include random access memory (RAM), flash memory, read-only memory (ROM), Erasable Programmable ROM (EPROM), Electronically Erasable and Programmable ROM (EEPROM), registers, hard disk, removable disk, CD-ROM, etc. It can be placed on a storage medium in the format of.
Since such a storage medium is connected to the processor, the processor can write information to the storage medium and read information from the storage medium. Such a storage medium may be integrated in the processor. The storage medium and processor may be located in the ASIC. Such ASICs may be located in base station devices, user devices, and small node devices. Such storage media and processors can also be arranged as independent components in base stations, user devices, and small node devices.
Although the present invention has been described in detail with reference to the above examples, it will be apparent to those skilled in the art that the invention is not limited to the examples described herein. The present invention can be realized with modifications and modifications without departing from the gist and scope of the invention as defined in the claims. Therefore, the description in the present specification is intended to give an example only, and does not impose any limitation on the present invention.
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| JP2004007279A | Cites | Japan | Y | Search report | 1-4,6-7,9-13,15-16,18-24,26,28-32,34-35 |
| US2009310561A1 | Cites | United States of America | Y | Search report | 1-4,6-7,9-13,15-16,18-24,26,28-32,34-35 |
| US2009310561A1 | Cites | United States of America | Y | Search report | 1-4,6-7,9-13,15-16,18-24,26,28-32,34-35 |
| JP2010258600A | Cites | Japan | Y | Search report | 1-4,6-7,9-13,15-16,18-24,26,28-32,34-35 |
| JP2010258600A | Cites | Japan | Y | Search report | 1-4,6-7,9-13,15-16,18-24,26,28-32,34-35 |
| JP2010501140A | Cites | Japan | A | Search report | – |
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| JP2010501140A | Cites | Japan | A | Search report | – |
50 members in 6 offices
Priority claims35
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Numbers
- Publication
- 2017099019
- Publication, DOCDB
- 2017099019
- Publication, EPODOC
- JP2017099019
- Application
- 15417
- Application, DOCDB
- 2017015417
- Application, EPODOC
- JP20170015417
Titles2
- Japanese
- ネットワークデバイス、ユーザ装置及び基地局
- English
- Network devices, user equipment and base stations
Classification
- CPC, 7
- H04W52/242
- H04W28/0864
- H04W52/383
- H04W76/14
- H04W76/15
- H04W36/00695
- H04W36/00692
- IPC, 3
- H04W76 02
- H04W92 20
- H04W16 26