System and method for performing handover in a broadband wireless access communication system
34 claims: 8 independent, 26 dependent
- 1広帯域無線接続通信システムで、サービング基地局(BS)によってハンドオーバーを制御する方法であって、 移動加入者端末機(MSS)のハンドオーバーの遂行を決定するステップと、 隣接BSに、前記サービングBSから前記MSSに提供するサービスの種類を含むサービス情報を送信するステップと、 前記隣接BSから、前記各隣接BSによって前記MSSに提供が可能なサービスの種類に関する情報を受信するステップと、 前記MSSに、前記MSSに現在提供されているサービスのうち、前記隣接BSから選択された各隣接BSによって提供可能な サービスの量を示す サービスレベル予告情報を含むハンドオーバー要請メッセージを送信するステップと、 前記MSSから、前記選択された隣接BSのうち、前記MSSによって選択されたターゲットBSに関する情報を含むハンドオーバー応答メッセージを受信するステップと、 前記ターゲットBSにハンドオーバー通知確認メッセージを送信するステップと、 を含み、 前記選択された隣接BSは、前記隣接BSによって前記MSSに提供可能なサービスの種類に関する情報を用いて、隣接BSから選択されていることを特徴とする方法。
- 2前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示すとともに、 前記第3情報は、全てのサービスが提供不可能であることを示すことを特徴とする、請求項1に記載の方法。
- 3前記選択された隣接BSのうち、前記MSSによって選択されたターゲットBSに関する情報は、前記ターゲットBSの基地局識別子(BSID)と、前記ターゲットBSのサービスレベル予告情報と、前記ターゲットBSから受信されたパイロットチャンネル信号のスキャンされたキャリアー対干渉雑音比(CINR)とを含むことを特徴とする、請求項2に記載の方法。
- 4広帯域無線接続通信システムで、移動加入者端末機(MSS)が行うハンドオーバーの制御方法であって、 サービング基地局(BS)から、前記MSSに現在提供されているサービスのうち、前記隣接BSから選択された各隣接BSによって提供可能な サービスの量を示す サービスレベル予告情報を含むハンドオーバー要請メッセージを受信するステップと、 前記選択された隣接BSから受信されたパイロットチャンネル信号のキャリアー対干渉雑音比(CINR)をスキャンするステップと、 前記サービスレベル予告情報及び前記スキャンされたCINRに基づいて前記選択された隣接BSのうち、ターゲットBSを選択するステップと、 前記サービングBSに、前記ターゲットBSに関する情報を含むハンドオーバー応答メッセージを送信するステップと、 を含み、 前記選択された隣接BSは、前記隣接BSによって前記MSSに提供可能なサービスの種類に関する情報を用いて、隣接BSから選択されていることを特徴とする方法。
- 5前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示すとともに、 前記第3情報は、全てのサービスが提供不可能であることを示すことを特徴とする、請求項4に記載の方法。
- 6前記選択された隣接BSから受信されたパイロットチャンネル信号のCINRをスキャンするステップは、 前記サービスレベル予告情報の優先順位に応じて前記選択された隣接BSを整列するステップと、 前記整列された隣接BSから受信されたパイロットチャンネル信号のCINRをスキャンするステップと、 を含むことを特徴とする、請求項4に記載の方法。
- 7前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示し、 前記第3情報は、全てのサービスが提供不可能であることを示すとともに、 前記第1情報の優先順位は、前記第2情報の優先順位よりも高く、かつ前記第2情報の優先順位は、前記第3情報の優先順位よりも高いことを特徴とする、請求項6に記載の方法。
- 8前記ターゲットBSに関する情報は、前記ターゲットBSの基地局識別子(BSID)と、前記ターゲットBSのサービスレベル予告情報と、前記ターゲットBSから受信されたパイロットチャンネル信号のスキャンされたキャリアー対干渉雑音比(CINR)とを含むことを特徴とする、請求項5に記載の方法。
- 9広帯域無線接続通信システムで、サービング基地局(BS)によるハンドオーバーを制御する方法であって、 移動加入者端末機(MSS)のハンドオーバーの遂行を決定するステップと、 前記隣接BSに、前記サービングBSから前記MSSに提供するサービスの種類を含むサービス情報を送信するステップと、 前記隣接BSから、前記各隣接BSによって前記MSSに提供が可能なサービスの種類に関する情報を受信するステップと、 前記MSSに、前記MSSに現在提供されているサービスのうち、前記隣接BSから選択された各隣接BSによって提供可能な サービスの量を示す サービスレベル予告情報を含むハンドオーバー要請メッセージを送信するステップと、 前記MSSから、前記選択された各隣接BSのサービスレベル予告情報を含む情報を有する第1ハンドオーバー応答メッセージを受信するステップと、 前記第1ハンドオーバー応答メッセージに含まれた情報に基づいてターゲットBSを選択するステップと、 前記ターゲットBSにハンドオーバー通知確認メッセージを送信するステップと、 前記MSSに、前記ターゲットBSに関する情報を含む第2ハンドオーバー応答メッセージを送信するステップと、 前記MSSから、ハンドオーバー指示メッセージを受信するステップと、 を含み、 前記選択された隣接BSは、前記隣接BSによって前記MSSに提供可能なサービスの種類に関する情報を用いて、隣接BSから選択されていることを特徴とする方法。
- 10前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示すとともに、 前記第3情報は、全てのサービスが提供不可能であることを示すことを特徴とする、請求項9に記載の方法。
- 11前記第1ハンドオーバー応答メッセージに含まれる情報は、前記選択された各隣接BSのサービスレベル予告情報と、前記選択された隣接BSから受信されたパイロットチャンネル信号のスキャンされたキャリアー対干渉雑音比(CINR)とを含むことを特徴とする、請求項9に記載の方法。
- 12前記ターゲットBSに関する情報は、前記ターゲットBSの基地局識別子(BSID)と、前記ターゲットBSのサービスレベル予告情報と、前記ターゲットBSから受信されたパイロットチャンネル信号のスキャンされたCINRと、前記ハンドオーバーの開始予想時刻と含むことを特徴とする、請求項9に記載の方法。
- 13広帯域無線接続通信システムで、移動加入者端末機(MSS)が行うハンドオーバー制御方法であって、 サービング基地局(BS)から、前記MSSに現在提供されているサービスのうち、隣接BSから選択された各隣接BSによって提供可能な サービスの量を示す 情報を含むハンドオーバー要請メッセージを受信するステップと、 前記選択された隣接BSから受信されたパイロットチャンネル信号のキャリアー対干渉雑音比(CINR)をスキャンするステップと、 前記サービングBSに、前記選択された各隣接BSのサービスレベル予告情報と前記スキャンされたCINRとを含む情報を有する第1ハンドオーバー応答メッセージを送信するステップと、 前記サービングBSから、前記MSSのハンドオーバーを行う前記ターゲットBSに関する情報を含む第2ハンドオーバー応答メッセージを受信するステップと、 前記サービングBSにハンドオーバー指示メッセージを送信するステップと、 を含み、 前記選択された隣接BSは、前記隣接BSによって前記MSSに提供可能なサービスの種類に関する情報を用いて、前記隣接BSから選択されていることを特徴とする方法。
- 14前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示すとともに、 前記第3情報は、全てのサービスが提供不可能であることを示すことを特徴とする、請求項13に記載の方法。
- 15前記ターゲットBSに関する情報は、前記ターゲットBSの基地局識別子(BSID)と、前記ターゲットBSのサービスレベル予告情報と、前記ターゲットBSから受信されたパイロットチャンネル信号のスキャンされたCINRと、前記ハンドオーバーの開始予想時刻とを含むことを特徴とする、請求項14に記載の方法。
- 16前記選択された隣接BSから受信されたパイロットチャンネル信号のCINRをスキャンするステップは、 前記サービスレベル予告情報の優先順位に応じて前記選択された隣接BSを整列するステップと、 前記整列された隣接BSから受信されたパイロットチャンネル信号のCINRをスキャンするステップと、 を含むことを特徴とする、請求項13に記載の方法。
- 17前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示し、 前記第3情報は、全てのサービスが提供不可能であることを示すとともに、 前記第1情報の優先順位は、前記第2情報の優先順位よりも高く、かつ前記第2情報の優先順位は、前記第3情報の優先順位よりも高いことを特徴とする、請求項16に記載の方法。
- 18広帯域無線接続通信システムで、ハンドオーバーを制御するシステムであって、 移動加入者端末機(MSS)と、 前記MSSのハンドオーバーの遂行を決定し、隣接BSに、サービングBSから前記MSSに提供するサービス情報を送信し、前記隣接BSから、前記各隣接BSが前記MSSに提供可能なサービスの種類に関する情報を受信し、前記MSSに、前記MSSに現在提供されているサービスのうち、隣接BSから選択された各隣接BSによって提供可能な サービスの量を示す サービスレベル予告情報を含むハンドオーバー要請メッセージを送信し、前記MSSから、前記選択されたBSのうち、前記MSSによって選択されたターゲットBSに関する情報を含むハンドオーバー応答メッセージを受信し、前記ターゲットBSに、ハンドオーバー通知確認メッセージを送信するサービング基地局(BS)と、 を含み、 前記選択された隣接BSは、前記隣接BSによって前記MSSに提供可能なサービスの種類に関する情報を用いて、隣接BSから選択されていることを特徴とするシステム。
- 19前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示すとともに、 前記第3情報は、全てのサービスが提供不可能であることを示すことを特徴とする、請求項18に記載のシステム。
- 20前記選択された隣接BSのうち、前記MSSによって選択されたターゲットBSに関する情報は、前記ターゲットBSの基地局識別子(BSID)と、前記ターゲットBSのサービスレベル予告情報と、前記ターゲットBSから受信されたパイロットチャンネル信号のスキャンされたキャリアー対干渉雑音比(CINR)とを含むことを特徴とする、請求項19に記載のシステム。
- 21広帯域無線接続通信システムで、ハンドオーバーを制御するシステムであって、 サービング基地局(BS)と、 前記サービングBSから、移動加入者端末機(MSS)に現在提供されているサービスのうち、隣接BSから選択された各隣接BSによって提供可能な サービスの量を示す サービスレベル予告情報を含むハンドオーバー要請メッセージを受信し、前記選択された隣接BSから受信されたパイロットチャンネル信号のキャリアー対干渉雑音比(CINR)をスキャンし、前記サービスレベル予告情報及び前記スキャンされたCINRに基づいて、前記選択された隣接BSからターゲットBSを選択し、前記サービングBSに、前記ターゲットBSに関する情報を含むハンドオーバー応答メッセージを送信する移動加入者端末機(MSS)と、 を含み、 前記選択された隣接BSは、前記隣接BSによって前記MSSに提供可能なサービスの種類に関する情報を用いて、隣接BSから選択されていることを特徴とするシステム。
- 22前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示すとともに、 前記第3情報は、全てのサービスが提供不可能であることを示すことを特徴とする、請求項21に記載のシステム。
- 23広帯域無線接続通信システムで、ハンドオーバーを制御するシステムであって、 移動加入者端末機(MSS)と、 前記MSSのハンドオーバーの遂行を決定し、隣接サービング基地局(BS)に、サービングBSから前記MSSに提供するサービスの種類を含むサービス情報を送信し、前記隣接BSから、前記各隣接BSが前記MSSに提供可能なサービスの種類に関する情報を受信し、前記MSSに、前記MSSに現在提供されているサービスのうち、隣接BSから選択された各隣接BSによって提供可能な サービスの量を示す サービスレベル予告情報を含むハンドオーバー要請メッセージを送信し、前記MSSから、前記選択された各隣接BSのサービスレベル予告情報を含む情報を有する第1ハンドオーバー要請メッセージを受信し、前記第1ハンドオーバー応答メッセージに含まれた情報に基づいてターゲットBSを選択し、前記ターゲットBSに、ハンドオーバー通知確認メッセージを送信し、前記MSSに、前記ターゲットBSに関する情報を含む第2ハンドオーバー応答メッセージを送信し、前記MSSから、ハンドオーバー指示メッセージを受信するサービング基地局(BS)と、 を含み、 前記選択された隣接BSは、前記隣接BSによって前記MSSに提供可能なサービスの種類に関する情報を用いて、前記隣接BSから選択されていることを特徴とするシステム。
- 24前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示すとともに、 前記第3情報は、全てのサービスが提供不可能であることを示すことを特徴とする、請求項23に記載のシステム。
- 25前記第1ハンドオーバー応答メッセージに含まれた情報は、前記選択された各隣接BSのサービスレベル予告情報と、前記選択された隣接BSから受信されたパイロットチャンネル信号のスキャンされたキャリアー対干渉雑音比(CINR)とを含むことを特徴とする、請求項24に記載のシステム。
- 26前記ターゲットBSに関する情報は、前記ターゲットBSの基地局識別子(BSID)と、前記ターゲットBSのサービスレベル予告情報と、前記ターゲットBSから受信されたパイロットチャンネル信号のスキャンされたキャリアー対干渉雑音比(CINR)と、前記ハンドオーバーの開始予想時刻とを含むことを特徴とする、請求項25に記載のシステム。
- 27前記ターゲットBSに関する情報は、前記ターゲットBSの基地局識別子(BSID)と、前記ターゲットBSのサービスレベル予告情報と、前記ターゲットBSから受信されたパイロットチャンネル信号のスキャンされたCINRとを含むことを特徴とする、請求項22に記載のシステム。
- 28前記MSSは、前記サービスレベル予告情報の優先順位に応じて前記選択された隣接BSを整列するとともに、前記整列された隣接BSから受信されたパイロットチャンネル信号のCINRをスキャンすることを特徴とする、請求項21に記載のシステム。
- 29前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示し、 前記第3情報は、全てのサービスが提供不可能であることを示すとともに、 前記第1情報の優先順位は、前記第2情報の優先順位よりも高く、かつ前記第2情報の優先順位は、前記第3情報の優先順位よりも高いことを特徴とする、請求項28に記載のシステム。
- 30広帯域無線接続通信システムで、ハンドオーバーを制御するシステムであって、 サービング基地局(BS)と、 前記サービングBSから、移動加入者端末機(MSS)に現在提供されているサービスのうち、隣接BSから選択された各隣接BSによって提供可能な サービスの量を示す 情報を含むハンドオーバー要請メッセージを受信し、前記選択された隣接BSから受信されたパイロットチャンネル信号のキャリアー対干渉雑音比(CINR)をスキャンし、前記サービングBSに、前記選択された各隣接BSの前記サービスレベル予告情報と前記スキャンされたCINRとを含む情報を有する第1ハンドオーバー応答メッセージを送信し、前記サービングBSから、前記MSSのハンドオーバーを行うターゲットBSに関する情報を含む第2ハンドオーバー応答メッセージを受信し、前記サービングBSに、ハンドオーバー指示メッセージを送信する移動加入者端末機(MSS)と、 を含み、 前記選択された隣接BSは、前記隣接BSによって前記MSSに提供可能なサービスの種類に関する情報を用いて、隣接BSから選択されていることを特徴とする、ことを特徴とするシステム。
- 31前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示し、 前記第3情報は、全てのサービスが提供不可能であることを示すことを特徴とする、請求項30に記載のシステム。
- 32前記ターゲットBSに関する情報は、前記ターゲットBSの基地局識別子(BSID)と、前記ターゲットBSのサービスレベル予告情報と、前記ターゲットBSから受信されたパイロットチャンネル信号のスキャンされたCINRと、前記ハンドオーバーの開始予想時刻と含むことを特徴とする、請求項31に記載のシステム。
- 33前記MSSは、前記サービスレベル予告情報の優先順位に応じて前記選択された隣接BSを整列するとともに、前記整列された隣接BSから受信されたパイロットチャンネル信号のCINRをスキャンすることを特徴とする、請求項30に記載のシステム。
- 34前記サービスレベル予告情報は、第1情報、第2情報、及び第3情報のうち1つを含み、 前記第1情報は、全てのサービスが提供可能であることを示し、 前記第2情報は、一部のサービスが提供可能であることを示し、 前記第3情報は、全てのサービスが提供不可能であることを示すとともに、 前記第1情報の優先順位は、前記第2情報の優先順位よりも高く、かつ前記第2情報の優先順位は、前記第3情報の優先順位よりも高いことを特徴とする、請求項33に記載のシステム。
Independent claims34
84 paragraphs, as filed
The present invention relates to a wideband wireless connection communication system, and more particularly, to a system and a method for performing a handover in a wideband wireless connection communication system using an orthogonal frequency division multiplexing method.
In the 4th generation ('4G') communication system, which is the next-generation communication system, in order to support a transmission speed of approximately 100 Mbps and provide users with services having various quality of service (Qos). Active research is being carried out. Current 3rd generation ('3G') communication systems support transmission speeds of approximately 384Kbps in outdoor channel environments with relatively poor channel environments, even in indoor channel environments with relatively good channel environments. Supports transmission speeds of up to 2 Mbps. On the other hand, a wireless short-range communication network (LAN) system and a wireless metropolitan area network (MAN) system generally support transmission speeds of 20 Mbps to 50 Mbps. Therefore, in the current 4G communication system, we will develop a new type of communication system that guarantees mobility and Qos with a wireless LAN system that guarantees a relatively high transmission speed and a wireless MAN system, and will provide it in the 4G communication system. Research is being actively conducted to support high-speed services.
However, the wireless MAN system has a wide service area and supports high-speed transmission speed, and is therefore suitable for supporting high-speed communication services. However, the user, that is, the subscriber terminal (SS: Subscriber Station) Since the system does not consider mobility at all, handover due to high-speed movement of SS is not considered. The wireless MAN system is a Broadband Wireless Access (BWA) communication system, which has a wider service area than a wireless LAN system and supports a higher transmission speed. A system that applies the Orthogonal Frequency Division Multiplexing (OFDM) method and the Orthogonal Frequency Division Multiplexing Access (OFDMA) method to support a broadband transmission network on the physical channels of the wireless MAN system. Is IEEE (Institute of Electrical and Electronics) Engineers) 802.16a communication system.
On the other hand, the above-mentioned IEEE 802.16a communication system is a system in which SS is currently fixed, that is, a state in which SS mobility is not considered at all and a single cell structure is considered. However, the IEEE 802.16e communication system is defined as a system considering the mobility of SS in the above-mentioned IEEE 802.16a communication system. Therefore, the above IEEE 802.16e system should consider the mobility of SS in a multi-cell environment. In order to provide SS mobility in such a multi-cell environment, it is inevitably required to change the operation of the SS and the base station (BS: Base Station). In order to support the mobility of the SS, research on SS handover considering the multiple cell structure is being actively conducted. Here, the SS having the above mobility is referred to as a mobile subscriber terminal (MSS: Mobile Subscriber Station).
Next, the structure of the above IEEE 802.16e communication system will be described with reference to FIG. FIG. 1 is a diagram showing the structure of a general IEEE 802.16e communication system. Referring to FIG. 1, the IEEE 802.16e communication system comprises a multi-cell structure having a first cell 100 and a second cell 150. Further, it includes a base station 110 that manages the cell 100, a base station 140 that manages the cell 150, and a large number of MSS111,113,130,151,153. Then, signal transmission / reception between the base stations 110,140 and MSS111,113,130,151,153 is performed by using the above-described OFDM / OFDMA system. Of the MSS111,113,130,151,153, the MSS130 exists in the boundary area between the cell 100 and the cell 150, that is, in the handover area. Therefore, mobility to the MSS 130 can only be supported when the handover to the MSS 130 is supported.
In the above IEEE 802.16e communication system, any MSS receives a pilot channel signal transmitted from a large number of base stations, and the carrier to interference and noise ratio (CINR) of the received pilot channel signal. To measure. After that, the MSS selects the base station that transmitted the pilot channel signal having the maximum CINR out of the many measured CINRs of the pilot channel signals, that is, the base station to which the MSS currently belongs, that is, the serving base station (Serving BS). ). That is, among the many base stations that transmit the pilot channel signal, the MSS recognizes the base station that transmits the pilot channel signal that the MSS can receive most smoothly as the base station to which the MSS belongs. As a result, the base station to which the MSS currently belongs becomes the serving base station. The MSS that selects the serving base station receives the downlink (downlink) frame and the uplink (uplink) frame transmitted from the serving base station. The above IEEE The structure of the downlink frame of the 802.16e communication system will be described with reference to FIG.
FIG. 2 is a diagram showing the structure of the downlink frame of a general IEEE 802.16e communication system. The downlink frame includes a preamble area 200, a broadcast control area 210, and a large number of time division multiplex (TDM) areas 220 and 230. Through the preamble area 200, a synchronization signal for acquiring mutual synchronization between the base station and the SS, that is, a preamble sequence is transmitted. The broadcast control area 210 is composed of a DL (DownLink) _MAP area 211 and a UL (UpLink) _MAP area 213. The DL_MAP area 211 is an area to which a DL_MAP message is transmitted. The information elements (IE: Information Element) included in the above DL_MAP message are shown in Table 1 below.
<tables num="1"><img file="JP4459232B2_D0001.tif" /></tables>
As shown in Table 1, DL_MAP messages are a large number of IEs, namely'Management Message Type', which indicates the type of message sent, and the modulation and demodulation methods applied to the physical channels to obtain synchronization. Indicates the'PHY (PHYsical) Synchronization'set according to, and the count corresponding to the configuration change of the downlink channel descript (DCD) message including the downlink burst profile (burst profile). Includes'DCD count',' Base Station ID' indicating the base station identifier (BSID), and'Number of DL_MAP Elements n'indicating the number of elements existing after the above Base Station ID. The DL_MAP message contains information for the ranging codes assigned to each of the ranging described below.
Further, the UL_MAP area 213 is an area to which a UL_MAP message is transmitted. Table 2 shows the IE included in the UL_MAP message above.
<tables num="2"><img file="JP4459232B2_D0002.tif" /></tables>
As shown in Table 2, UL_MAP messages include a large number of IEs, namely'Management Message Type', which indicates the type of message sent,'Uplink Channel ID', which indicates the uplink channel identifier, and uplink burst profile. 'UCD count', which indicates the count corresponding to the composition change of the Uplink Channel Descript (UCD) message including, and'Number of UL_MAP Elements n', which indicates the number of elements existing after the UCD count. including. Here, the uplink channel identifier is uniquely assigned in the media access control (MAC) sublayer.
The UIUC (Uplink Interval Usage Code) area is an area of information that specifies the usage of the offset recorded in the offset area. For example, if a value of 2 is recorded in the UIUC area, it means that the start offset used for the initial rangening is recorded in the offset area. Moreover, if the value of 3 is recorded in the UIUC area, it means that the start offset used for the band request range or the retention management range is recorded in the offset area. In the offset area, as described above, the start offset value used for the initial range, the band request range, or the retention management range is recorded according to the information recorded in the UIUC area. Further, the characteristics of the physical channel transmitted in the UIUC area are recorded in the UCD message. If the MSS does not perform the range successfully, it decides an arbitrary backoff value, delays it by the backoff time, and then tries the ranger again in order to increase the probability of success in the next attempt. At this time, the information necessary for determining the backoff value is also included in the UCD message. The structure of the UCD message is explained in more detail with reference to Table 3 below.
<tables num="3"><img file="JP4459232B2_D0003.tif" /></tables>
As shown in Table 3, UCD messages are counted by a large number of IEs, namely'Management Message Type', which indicates the type of message sent, and'Uplink Channel ID', which indicates the uplink channel identifier. 'Configuration Change Count',' Mini-slot Size', which indicates the number of mini-slots on the uplink physical channel, and'Mini-slot Size', which indicates the starting point of the backoff for initial range-up (ie, initial range-up). 'Ranging Backoff Start' which indicates the size of the first backoff window for and'Ranging Backoff End' which indicates the end point of the backoff for the above initial rangeing (ie indicates the size of the final backoff window) , Indicates the start point of the backoff for contention data and requests (ie, indicates the size of the first backoff window)'Request Backoff Start', and contention data and Includes'Request Backoff End', which indicates the end point of the backoff for requests (ie, the size of the final backoff window). Here, the above backoff value indicates a kind of standby time value that should wait for the next range if the range fails, and the base station waits for the next range if the MSS fails in the range. The backoff value, which is the time information to be used, should be transmitted to the above MSS. For example, if the above Ringing Backoff Start and Ringing Backoff End values are set to 10, the MSS will be 2 by the truncated binary exponential backoff algorithm.<sup>10</sup>After parsing the opportunity to perform one range (ie, 1024), the next range must be done.
Further, the TDM areas 220 and 230 are areas corresponding to time slots assigned to each MSS by the time division multiplexing (TDM) / time division multiple access (TDMA) method. The base station uses a preset center carrier to transmit broadcast information to be broadcast to the MSS managed by the base station through the DL_MAP area 211 of the downlink frame. When the MSS is powered on, it monitors all preset frequency bands for each of the MSSs to detect the pilot channel signal with the highest pilot CINR. Then, the base station that has transmitted the pilot channel signal having the maximum pilot CINR is determined as the base station to which the MSS currently belongs, and the DL_MAP area 211 and UL_MAP area 213 of the downlink frame transmitted by the base station are determined. Check and confirm the control information that controls your own uplink and downlink and the information that indicates the actual data transmission / reception position.
FIG. 3 is a diagram showing the structure of the uplink frame of a general IEEE 802.16e communication system. Prior to the description of FIG. 3, the rangings used in the above-mentioned IEEE 802.16e communication system, that is, the initial ranging, the retention management ranging (that is, the periodic ranging), and the bandwidth request ranging will be described. ..
First, the initial ranging will be described. The initial range is the range performed when the base station requests the base station to obtain synchronization with the MSS. Further, the initial range is the range performed to adjust the transmission power by adjusting the accurate time offset between the MSS and the base station. That is, when the MSS is powered on, it receives DL_MAP messages, UL_MAP messages, and UCD messages to obtain synchronization with the base station, and then adjusts the time offset and transmission power with the base station. Perform initial ranging. Here, since the above-mentioned IEEE 802.16e communication system uses the OFDM / OFDMA method, the above-mentioned range-up procedure requires a range-up subchannel and a range-up code. The base station assigns a range code that can be used according to the purpose of each range, that is, the type. A specific explanation of this is as follows.
The above range cord has a predetermined length (for example, 2).<sup>15</sup>It is generated by segmenting a pseudo-random noise (PN) sequence with a length of -1 bit (PN) in a predetermined unit. Generally, two ranging subchannels having a length of 53 bits constitute one ranging channel, and the PN code is segmented through the ranged channel having a length of 106 bits to form a ranging code. Up to 48 range codes (RC # 1 to RC # 48) configured in this way can be assigned to MSS, and a minimum of 2 range codes per MSS as the initial (default) value are the above three types. It applies to the desired range, namely initial range, periodic range and band-requested range. In this way, different range code is assigned to each of the above three types of target range. For example, N Nranging Codes are assigned for initial ranging (N RC (Ranging Code) s for initial ranging) and M Nranging Codes are assigned for periodic ranging (M RCs for periodic). ranging), L ranging codes are assigned to bandwidth request ranging (L RCs for BW-request ranging). As described above, the range code assigned in this way is transmitted to the MSS through the DL_MAP message, and the MSS performs the range procedure using the range code included in the DL_MAP message according to its purpose.
Secondly, periodic rangening will be described. The periodic rangening indicates a range range performed periodically by the MSS whose time offset and transmission power are adjusted with the base station through the initial range range in order to adjust the state of the base station and the channel. The MSS performs periodic rangening using a range code assigned for periodic rangening.
Thirdly, the band request rangening will be described. The band request range is a range in which the MSS whose time offset and transmission power are adjusted with the base station through the initial range requests a bandwidth allocation for actual communication with the base station. The bandwidth request range is performed by selecting one of the Grants method, the Contention-based Focused bandwidth requests for Wireless MAN-OFDM method, and the Contention-based CDMA bandwidth requests for Wireless MAN-OFDMA method. Here, each of the Grants method, Contention-based Focused bandwidth requests for Wireless MAN-OFDM method, and Contention-based CDMA bandwidth requests for Wireless MAN-OFDMA method will be described.
(1) Grants method The Grants method is a method of requesting bandwidth allocation when the communication system to which the MSS currently belongs is a communication system using a single carrier. In this case, the MSS performs bandwidth request range using an initial CID that is not its own connection identifier (CID: Connection ID). If the band request range fails, the MSS attempts the band request range again after the backoff value preset according to the information recently received from the base station and the request state of the base station. Or, decide to discard the received Service Data Unit (SDU). Here, MSS is UCD messages are sensing the backoff value through a di.
(2) Contention-based Focused bandwidth requests for Wireless MAN-OFDM method The Contention-based Focused bandwidth requests for Wireless MAN-OFDM method is a method of requesting bandwidth allocation when the communication system to which the MSS currently belongs is a communication system using the OFDM method. The Contention-based Focused bandwidth requests for Wireless MAN-OFDM method can be divided into two types. The first method is a method in which the MSS uses the default CID and sends a Focused Contention Transmission message to perform bandwidth request range as described in the Grants method above, and the second method is the default method. This is a method of performing band request range by transmitting the broadcast CID together with the OFDM Focused Contention ID without using the CID. OFDM the above broadcast CID When transmitting with the Focused Contention ID for bandwidth request range, the base station determines the specific connected channel and transmission probability for the MSS.
(3) Contention-based CDMA bandwidth requests for Wireless MAN-OFDMA method The Contention-based CDMA bandwidth requests for Wireless MAN-OFDMA method is a method of requesting bandwidth allocation when the system to which the MSS currently belongs uses the OFDMA method. The Contention-based CDMA bandwidth requests for Wireless MAN-OFDMA method can also be divided into two types. The first method is a method of performing bandwidth request range as described in the Grants method above, and the second method is a method of performing band request range using a mechanism based on the CDMA method, that is, a CDMA based mechanism. Is. Here, the above CDMA based In the mechanism-based system, the communication system uses a large number of tones consisting of OFDM symbols, that is, a large number of subchannels. Therefore, when the MSS performs band request range, the base station is assigned to each of the large number of subchannels. Apply a mechanism like the CDMA system. When the base station successfully receives the band-requested range, the frequency band is allocated to the MSS that has performed the band-requested range through the MAC protocol data unit (PDU). On the other hand, when the REQ (REQuest) Region-Focused method is used, if a large number of MSS try band request range using the same contention code through the same subchannel, the possibility of collision increases.
Referring to FIG. 3, the uplink frame includes an Initial Maintenance Opportunities area 300 for initial range and retention management range (ie, periodic range), a Request Contention Opportunities area 310 for bandwidth request range, and an MSS. Contains the MSS scheduled data area 320, which contains the uplink data of. The Initial Maintenance Opportunities region 300 actually includes a large number of connection burst sections including initial range and periodic range, and a collision section when a collision occurs between the large number of connection burst sections. The Request Contention Opportunities area 310 includes a large number of band request sections including band request range, and a collision section when a collision occurs between the large number of band request sections. Further, the MSS scheduled data area 320 is a large number of MSS scheduled data areas (that is, MSS 1 scheduled data area ~ MSS N). It is composed of a scheduled data region), and there are MSS transition gaps between the large number of MSS scheduled data regions.
FIG. 4 is a flow chart showing the first range process between the base station and the MSS of a general IEEE 802.16e communication system. The MSS400 monitors all preset frequency bands of the MSS400 to detect the pilot channel signal with the highest CINR. The MSS400 then determines the base station 420 that transmitted the pilot channel signal with the highest CINR as the base station 420 to which the MSS400 currently belongs (ie, the serving base station), and the downlink transmitted from the serving base station 420. Receives the preamble of the frame and obtains system synchronization with the serving base station 420.
As described above, if system synchronization between the MSS 400 and the serving base station 420 is achieved, the serving base station 420 sends a DL_MAP message and a UL_MAP message to the MSS 400 (steps 411, 413). Here, the DL_MAP message is, as explained in Table 1, the information required for the MSS400 to obtain synchronization with the serving base station 420 on the downlink and the physical ability to receive the message transmitted to the MSS400 on the downlink. It functions to inform the MSS400 of information such as the channel structure. In addition, the UL_MAP message functions as an uplink to inform the MSS400 of information such as the MSS scheduling cycle and the structure of the physical channel, as explained in Table 2. On the other hand, the DL_MAP message is periodically broadcast from the base station to all MSSs, but the case where any MSS can continuously receive the DL_MAP message is expressed as being synchronized with the base station. That is, the MSS that has received the DL_MAP message can receive all the messages transmitted through the downlink. And, as explained in Table 3, when the MSS fails to access, the base station sends a UCD message to the MSS containing information notifying the available backoff value.
On the other hand, when the MSS 400 that has acquired synchronization with the serving base station 420 performs the range, the MSS 400 transmits a range request (RNG_REQ: Ranging Request) message to the serving base station 420 in step 415. Then, in step 417, the serving base station 420 that has received the RNG_REQ message transmits a Ranging Response (RNG_RSP) message including information for correcting the frequency, time, and transmission power for the range to the MSS400. To do. Table 4 below shows the structure of the above RNG_REQ message.
<tables num="4"><img file="JP4459232B2_D0004.tif" /></tables>
In Table 4, the'Downlink Channel ID'indicates the downlink channel identifier included in the ranging request message received by the MSS400 through the UCD, and the'Pending Until Complete'indicates the priority of the ranged response transmitted. That is, if the Pending Until Complete is 0, the previous ranging response has priority, and if the Pending Until Complete is not 0, the currently transmitted ranging response has priority. The structure of the RNG_RSP message corresponding to the RNG_REQ message shown in Table 4 is shown in Table 5.
<tables num="5"><img file="JP4459232B2_D0005.tif" /></tables>
In Table 5,'Uplink Channel ID' indicates the uplink channel identifier included in the RNG_REQ message.
On the other hand, when the OFDMA method is used in the IEEE 802.16e communication system, a dedicated section for ranging is set so that the first ranging process as described above can be performed more efficiently, and the ranging code is transmitted in the dedicated section. Delegate the RNG_REQ message using the method. When the method of transmitting the range code only in the dedicated section is used, the range process between the base station and the MSS will be described with reference to FIG. FIG. 5 is a flow chart showing a second rangeing process between the base station and the MSS of a general IEEE 802.16e communication system. With reference to FIG. 5, the second range process between the base station and the MSS is basically the same as the first range process described with reference to FIG. However, before the MSS500 sends the RNG_REQ message, it sends a ranging code to the serving base station 520 (step 515). Then, the serving base station 520 receives the ranging code and sends an RNG_RSP message to the MSS500 (step 517). Upon receiving the RNG_RSP message, the MSS500 transmits the RNG_REQ message to the serving base station 520 in the non-competitive (contention-free) band specified by the serving base station 520 (step 519).
On the other hand, the base station inserts the response information for the received range code into the RNG_RSP message. In this case, the new information contained in the RNG_RSP message is as follows. a.Ranging Code: Received ranging CDMA code b.Ranging Symbol: OFDM symbol in the received ranging CDMA code above c.Ranging subchannel: The ranging subchannel in the received ranging CDMA code above. d.Ranging frame number: Frame number in the received ranging CDMA code above
As described above, the IEEE 802.16e communication system is a communication system that considers the mobility and the multi-cell structure of the MSS, but no specific procedure for the handover of the MSS has been proposed at present. Therefore, development for the MSS handover procedure is needed.
<p> Therefore, an object of the present invention for solving the problems caused by the above-mentioned conventional techniques is to provide a system and a method for performing a handover of a mobile subscriber terminal (MSS) in a wideband wireless connection communication system. Another object of the present invention is to provide a system and a method for performing a handover of a mobile subscriber terminal by a serving base station control in a wideband wireless connection communication system. Another object of the present invention is to provide a system and a method for performing a handover of a mobile subscriber terminal according to a service level that can be supported by a wideband wireless connection communication system.</p>
<p> In order to achieve such an object, according to one aspect of the present invention, the mobile subscriber terminal, the serving base station providing the service to the mobile subscriber terminal, and the serving base station adjacent to the mobile subscriber terminal. A system that controls the handover of the mobile subscriber terminal by the serving base station in a broadband wireless connection communication system having a plurality of adjacent base stations, and performs the handover of the mobile subscriber terminal. It is determined, the service information including the type of service provided to the mobile subscriber terminal is notified to the adjacent base station, and the information regarding the type of service that each adjacent base station can provide is received from the adjacent base station. , The handover request signal including the information received from the adjacent base station is transmitted to the mobile subscriber terminal, and the mobile subscriber terminal is selected from the adjacent base stations by the mobile subscriber terminal. A serving base station that receives information on one adjacent base station and confirms a handover notification to the selected adjacent base station, and a handover request signal including information received from the serving base station from the adjacent base station. Receive, select one adjacent base station from the adjacent base stations corresponding to the received information and transmit it to the serving base station, transmit the handover start signal to the serving base station, and transmit the handover start signal to the selected adjacent base station. It is characterized by including a mobile subscriber terminal that performs a handover to a base station.</p><p> According to another aspect of the present invention, the mobile subscriber terminal, the serving base station providing the service to the mobile subscriber terminal, and the plurality of adjacent base stations adjacent to the serving base station are provided. It is a system that controls the handover of the mobile subscriber terminal by the serving base station in the broadband wireless connection communication system, determines the execution of the handover of the mobile subscriber terminal, and determines the handover of the mobile subscriber terminal. Notify the adjacent base station of service information including the type of service provided to the machine, receive information on the type of service that each adjacent base station can provide from the adjacent base station, and send the mobile subscriber terminal to the mobile subscriber terminal. A handover request signal including the information received from the adjacent base station is transmitted, a response signal corresponding to the handover request signal is received from the mobile subscriber terminal, and the neighboring base station included in the response signal is related. A serving base station that selects one adjacent base station in consideration of information and confirms a handover notification to the selected adjacent base station, and a handover including information received from the serving base station from the adjacent base station. The request signal is received, the response signal corresponding to the handover request signal is transmitted to the serving base station, the information about the adjacent base station performing the handover is received from the serving base station, and the handover is performed to the serving base station. It is characterized by including a mobile subscriber terminal that transmits a start signal and performs a handover to the selected adjacent base station.</p><p> According to yet another aspect of the present invention, a mobile subscriber terminal, a serving base station providing a service to the mobile subscriber terminal, and a plurality of adjacent base stations adjacent to the serving base station. A method of controlling the handover of the mobile subscriber terminal by the serving base station, the step of determining the execution of the handover of the mobile subscriber terminal, and the movement of the broadband wireless connection communication system. After deciding to perform the handover of the subscriber terminal, the step of transmitting the service information including the type of service provided to the mobile subscriber terminal from the serving base station to the adjacent base station, and the step of transmitting the service information to the adjacent base station, and the adjacent base station. From the above, a step of receiving information on the types of services that can be provided by each of the adjacent base stations, and a step of transmitting a handover request signal including the information received from the adjacent base station to the mobile subscriber terminal. , The step of receiving a handover response signal indicating one of the adjacent base stations selected by the mobile subscriber terminal from the mobile subscriber terminal, and the selected adjacent base station. It is characterized by including a step of transmitting a handover notification confirmation signal.</p><p> Further, according to still another aspect of the present invention, a mobile subscriber terminal, a serving base station providing services to the mobile subscriber terminal, and a plurality of adjacent bases adjacent to the serving base station. A broadband wireless connection communication system having a station, which is a handover control method performed by the mobile subscriber terminal, and receives a handover request signal including information received from the adjacent base station from the serving base station. Steps to select one of the adjacent base stations corresponding to the received information, and transmit a response signal indicating the selected adjacent base station to the serving base station, and the serving base. It is characterized by including a step of transmitting a handover start signal to a station and performing a handover to the selected adjacent base station.</p><p> According to yet another aspect of the present invention, a mobile subscriber terminal, a serving base station providing a service to the mobile subscriber terminal, and a plurality of adjacent base stations adjacent to the serving base station. A method of controlling the handover of the mobile subscriber terminal by the serving base station, the step of determining the execution of the handover of the mobile subscriber terminal, and the movement of the broadband wireless connection communication system. After deciding to perform the handover of the subscriber terminal, the step of transmitting the service information including the type of service provided to the mobile subscriber terminal from the serving base station to the adjacent base station, and the step of transmitting the service information to the adjacent base station, and the adjacent base station. From the above, a step of receiving information on the types of services that can be provided by each of the adjacent base stations, and a step of transmitting a handover request signal including the information received from the adjacent base station to the mobile subscriber terminal. , A step of receiving a response signal corresponding to the handover request signal from the mobile subscriber terminal, and a step of selecting one adjacent base station in consideration of information about the adjacent base station included in the response signal. It is characterized by including a step of confirming the handover notification to the selected adjacent base station.</p><p> Further, according to still another aspect of the present invention, a mobile subscriber terminal, a serving base station providing services to the mobile subscriber terminal, and a plurality of adjacent bases adjacent to the serving base station. In a broadband wireless connection communication system having a station, which is a handover control method performed by the mobile subscriber terminal, a handover request signal including information received from the adjacent base station is received from the serving base station. A step of transmitting a response signal corresponding to the handover request signal to the serving base station, and a step of receiving information from the serving base station regarding an adjacent base station that performs the handover of the mobile subscriber terminal. It is characterized by including a step of transmitting a handover start signal to the serving base station and performing a handover to the selected adjacent base station.</p>
<p> As described above, the present invention enables load distribution of the serving base station and improves the performance of the system by controlling the handover of the MSS in response to the request of the serving base station. That is, the load concentrated on a specific base station can be distributed to a large number of base stations, so that the overall performance of the system is improved. In addition, when the serving base station controls the handover of the MSS, by notifying the adjacent base station capable of the handover of the MSS in advance, it is possible to reduce the load and power consumption due to scanning of the pilot channel signal of the MSS.</p>
Hereinafter, preferred embodiments of a system and method for performing handover in the wideband wireless connection communication system according to the present invention will be described in detail with reference to the accompanying drawings. In the following description, for the purpose of clarifying only the gist of the present invention, specific description of related known functions or configurations will be omitted.
FIG. 6 is a flow chart showing a handover process at the request of a Serving Base Station (BS) according to the first embodiment of the present invention. First, it is clear that the present invention can be applied to a Broadband Wireless Access (BWA) communication system, and for convenience of explanation, IEEE (Institute of Electrical and Electronics Engineers) 802.16e, which is a kind of wideband wireless connection communication system. A communication system will be described as an example. Further, although not shown in FIG. 6, the Mobile Subscriber Station (MSS) 600 receives pilot channel signals transmitted from a large number of base stations. The MSS600 is a Carrier to Interference and Noise (CINR) of the received pilot channel signal. Ratio) is measured. The MSS600 selects the base station that transmits the pilot channel signal having the largest CINR out of the CINRs of the large number of measured pilot channel signals as the base station to which the MSS600 currently belongs, that is, the serving base station.
The serving base station 610 sends a Neighbor Discovery (MOB_NBR_ADV: Mobile Neighbor Advertisement) message to the MSS600. The MSS600 can obtain information about neighboring base stations by receiving the MOB_NBR_ADV message. The information elements (IE: Information Element) included in the above MOB_NBR_ADV message are as shown in Table 6 below.
<tables num="6"><img file="JP4459232B2_D0006.tif" /></tables>
As shown in Table 6, MOB_NBR_ADV messages are for a large number of IEs, namely'Management Message Type', which indicates the type of message sent,'Configuration Change Count', which indicates the number of change configurations, and adjacent base stations. Not only the above information,'N_NEIGHBORS' indicating the number,'Neighbor BS-ID' indicating the identifier (ID: Identifier) of the adjacent base station,'Physical Frequency' indicating the physical channel frequency of the adjacent base station, and the above information. , Other information related to the adjacent base station, i.e., other adjacent information (TLV Encoded Neighbor Information) indicating information for a physical channel. Here, if the above Configuration Change Count has the same value as the previous value, it indicates that the currently received MOB_NBR_ADV message has the same content as the previously received MOB_NBR_ADV message, and the above Configuration Change If Count has a different value than the previous value, it indicates that the currently received MOB_NBR_ADV message is different from the previously received MOB_NBR_ADV message.
As described above, the serving base station 610 determines the handover of the MSS 600 while the MSS 600 is aware of the information of the adjacent base station. Here, determining the handover of the MSS 600 by the serving base station 610 may be executed for load distribution of the serving base station 610 and the like. After the serving base station 610 determines the handover of the MSS600, the serving base station 610 is handed over to each of the MSS600 adjacent base stations, for example, the first adjacent base station 620, the second adjacent base station 630, and the third adjacent base station 640. Send a notification (HO_notification) message (step 613, step 615 and step 617). The structure of the HO_notification message is shown in Table 7.
<tables num="7"><img file="JP4459232B2_D0007.tif" /></tables>
As shown in Table 7, HO_notification messages are handed to a number of IEs, namely the first adjacent base station 620, the second adjacent base station 630, or the third adjacent base station 640, which are adjacent base stations. The identifier of the MSS600 that is going to be over (ie, the MSS unique identifier), the time when the MSS600 is expected to start the handover, and the adjacent base station where the MSS600 becomes the new serving base station, that is, the target base station. Includes information such as the required bandwidth and quality of service (Qos) level. Here, the bandwidth indicates the bandwidth required for the service provided by the current serving base station 610 to the MSS600.
Each of the first adjacent base station 620, the second adjacent base station 630, and the third adjacent base station 640 that received the above HO_notification message sends a handover notification response (HO_notification_response) message, which is a response message to the HO_notification message. Transmit to serving base station 610 (step 619, step 621 and step 623). The structure of the above HO_notification_response message is shown in Table 8 below.
<tables num="8"><img file="JP4459232B2_D0008.tif" /></tables>
As shown in Table 8, the HO_notification_response message contains a large number of IEs, that is, the identifier of the MSS that is going to be handed over to the adjacent base station, and whether or not the adjacent base station can perform the handover in response to the MSS handover request. Includes an acknowledgment (ACK / NACK) and bandwidth and service level information that each of the adjacent base stations can provide when the MSS hands over to each adjacent base station.
The serving base station 610 that has received the HO_notification_response message from each of the first adjacent base station 620, the second adjacent base station 630, and the third adjacent base station 640 refers to the received HO_notification_response message and makes the first one. It is determined whether each of the adjacent base station 620, the second adjacent base station 630, and the third adjacent base station 640 can provide the service currently provided to the MSS 600 by the serving base station 610. The serving base station 610 sends a base station handover request (MOB_BSHO_REQ) message to the MSS600 according to the determination result of the service provision (step 625). That is, the serving base station 610 refers to the HO_notification_response message received from each of the first adjacent base station 620, the second adjacent base station 630, and the third adjacent base station 640, and the MSS 600 can hand over the adjacent base. Set the station in advance. In the following description, it is assumed that the serving base station 610 determines only the first adjacent base station 620 and the second adjacent base station 630 as handover-capable adjacent base stations. The structure of the above MOB_BSHO_REQ message is shown in Table 9 below.
<tables num="9"><img file="JP4459232B2_D0009.tif" /></tables>
As shown in Table 9, the MOB_BSHO_REQ message includes'N_Recommended', which is information for the neighboring base stations that can be handed over in consideration of the services currently provided to the MSS600 among the neighboring base stations of the MSS600. .. Here, N_Recommended includes the identifier (Neighbor BS-ID) of the neighboring base station capable of handover and the service level prediction (Service Level Prediction) information. The serving base station 610 can also configure the MOB_BSHO_REQ message in a form in which the adjacent base stations are arranged according to the priority of the service level notice. Here, the service level notice information is information indicating the amount of services that can be provided by the adjacent base station among the services currently provided to the MSS600. The service level notice information is as follows. Service Level Prediction = 2: All services can be provided. Service Level Prediction = 1: Some of all services can be provided. Service Level Prediction = 0: Not all services can be provided.
Upon receiving the MOB_BSHO_REQ message, the MSS600 scans the CINR of the pilot channel signals of the adjacent base stations contained in the MOB_BSHO_REQ message, that is, the first adjacent base station 620 and the second adjacent base station 630 ( Step 627). Here,'measuring the CINR of the pilot channel signal' or'scanning the CINR of the pilot channel signal'indicates the determination of CINR in the same meaning. Further, as described above, when the adjacent base station receives the MOB_BSHO_REQ message having the form arranged according to the priority of Service Level Prediction, the MSS600 receives the CINR of the pilot channel signal of the adjacent base station according to the priority. To scan. The MSS600 then sends an MSS Handover Response (MOB_MSSHO_RSP) message containing the CINR of the scanned adjacent base station pilot channel signal to the serving base station 610 (step 629).
Then, the process in which the MSS600 measures the CINR of the pilot channel signal of the adjacent base station in response to the reception of the MOB_BSHO_REQ message and transmits the MOB_MSSHO_RSP message including the measurement result to the serving base station 610 will be described in detail later. Here, the MSS600 can select the target base station to be handed over by the MSS600 by referring to the CINR measurement result and / or the service level prediction of the pilot channel signal of the adjacent base station. In this case, the MSS600 sends a MOB_MSSHO_RSP message containing the identifier of the selected target base station and / or the CINR of the target base station. The structure of the above MOB_MSSHO_RSP message is shown in Table 10.
<tables num="10"><img file="JP4459232B2_D0010.tif" /></tables>
As shown in Table 10, the MOB_MSSHO_RSP message includes the CINR of the adjacent base station measured by the MSS600 and the Service Level Prediction information of the adjacent base station received and recognized from the serving base station. That is, the Service Level Prediction has the same value as the Service Level Prediction included in the MOB_BSHO_REQ message. As mentioned above, when the MSS600 selects a target base station, the MOB_MSSHO_RSP message contains the CINR measurement result of the target base station selected by the MSS600 instead of the CINR measurement result of the adjacent base station included in the MOB_BSHO_REQ message. Is done. In FIG. 6, it is assumed that the MSS 600 selects a second adjacent base station 630 as the target base station.
When the serving base station 610 receives the MOB_MSSHO_RSP message, it recognizes that the target base station to be handed over by the MSS600 is the second adjacent base station 630, and indicates that the MSS600 is handed over to the second adjacent base station 630. Send a handover notification confirmation (HO_notification_confirm) message (step 631). The structure of the HO_notification_confirm message is shown in Table 11.
<tables num="11"><img file="JP4459232B2_D0011.tif" /></tables>
As shown in Table 11, the HO_notification_confirm message contains the identifier of the MSS that is trying to hand over to a large number of IEs, that is, the selected target base station, and the above target base when the MSS hands over to that target base station. Includes bandwidth and QoS level information provided by the station. On the other hand, when the second adjacent base station 630 receives the HO_notification_confirm message, the MSS600 sends an RNG_REQ message to the UL_MAP message within a predetermined time so that the MSS600 can perform a high-speed handover to the second adjacent base station 630. The frequency band and / and the ranging code can be specified as desired. Here, specifying the frequency band and / and the range code so that the MSS600 can send the RNG_REQ message is defined as assigning'Fast Ranging_IE'.
Then, the MSS 600 sends a handover instruction (HO_IND: Handover Indication) message to the serving base station 610 to notify the second adjacent base station 630, which is the target base station, of the start of the handover procedure (step 633). The structure of the above HO_IND message is shown in Table 12 below.
<tables num="12"><img file="JP4459232B2_D0012.tif" /></tables>
As shown in Table 12, the HO_IND message contains a number of IEs, namely the'Management Message Type', which indicates the type of message sent, the identifier of the final target base station selected by the MSS, and the above information. Also includes other information (TLV Encoded Information) that indicates other relevant information.
Upon receiving the HO_IND message from the MSS600, the serving base station 610 breaks the link currently set up with the serving base station 610 (step 635). When the link with the serving base station 610 is released in this way, the MSS 600 performs a handover with the second adjacent base station 630. That is, the MSS600 receives the UL_MAP message (including Fast Ranging_IE) transmitted from the second adjacent base station 630 (step 637) and uses the Fast Ranging_IE to transmit the RNG_REQ message to the second adjacent base station 630. (Step 639). Upon receiving the RNG_REQ message, the second adjacent base station 630 transmits a Ranging Response (RNG_RSP) message containing information for correcting the frequency, time, and transmission power for rangeing to the MSS600 (step 641). ). Upon receiving the RNG_RSP message in this way, the MSS600 performs an initial network entry operation with the second adjacent base station 630 (step 643).
FIG. 7 is a signal flow diagram showing a handover process at the request of the serving base station according to the second embodiment of the present invention. The handover process shown in FIG. 7 is basically the same as the handover process described with reference to FIG. 6, except that the serving base station 610 selects the target base station to be handed over by the MSS600. That is, the operation from step 711 to step 727 shown in FIG. 7 is the same as the operation from step 611 to 627 in FIG. 6, and the operation from step 735 to step 745 in FIG. 7 is the step in FIG. It is the same as the operation from 633 to step 643. However, in FIG. 7, since the MSS600 does not select the target base station but the serving base station 610 selects it, the base station handover response (MOB_BSHO_RSP) that notifies the MSS600 of the selection result of the target base station by the serving base station 610. Includes additional steps for sending the message. Further, step 729 is different from step 629 in FIG.
The MSS600 serves by inserting the CINR result and / or Service Level Prediction of the pilot channel signals of the neighboring base stations that can be handed over, that is, the first adjacent base station 620 and the second adjacent base station 630, into the MOB_MSSHO_RSP message. Send to base station 610 (step 729). The serving base station 610 is a target to be handed over by the MSS600 by referring to the CINR result and the service level prediction of the pilot channel signals of the first adjacent base station 620 and the second adjacent base station 630 included in the MOB_MSSHO_RSP message. Select a base station. In the handover process shown in FIG. 7, it is assumed that the second adjacent base station 630 is determined as the target base station as in the case shown in FIG. The serving base station 610 then sends a MOB_BSHO_RSP message to the MSS600 indicating that it determines the second adjacent base station 630 as the target base station (step 733). The structure of the MOB_BSHO_RSP message is shown in Table 13 below.
<tables num="13"><img file="JP4459232B2_D0013.tif" /></tables>
As shown in Table 13, the MOB_BSHO_RSP message contains a large number of IEs, namely'Management Message Type', which indicates the type of message sent, the expected start time of the handover procedure, and the target base selected by the serving base station. Contains information for the station.
FIG. 8 is a flowchart showing an operation process of a serving base station that performs handover according to the first embodiment of the present invention. First, the serving base station 610 determines the handover of the MSS600 in step 811 and then proceeds to step 813. In step 813, the serving base station 610 sends a HO_notification message to the MSS600's adjacent base stations, namely the first adjacent base station 620, the second adjacent base station 630, and the third adjacent base station 640, and then proceeds to step 815. move on. In step 815, the serving base station 610 receives the HO_notification_response message as a response to the HO_notification message from the first adjacent base station 620, the second adjacent base station 630, and the third adjacent base station 640, and then proceeds to step 817. In step 817, the serving base station 610 receives a service level from the first adjacent base station 620, the second adjacent base station 630, and the third adjacent base station 640. With reference to Prediction, the MSS600 selects an adjacent base station that can be handed over, that is, the first adjacent base station 620 and the second adjacent base station 630, and the selected first adjacent base station 620 and the second. After sending a MOB_BSHO_REQ message containing information about the neighboring base station 630 to the MSS600, the process proceeds to step 819.
In step 819, the serving base station 610 receives a MOB_MSSHO_RSP message from the MSS600 containing information about the second adjacent base station 630, which is the target base station, and then proceeds to step 821. Here, in the first embodiment of the present invention, since the MSS600 selects the target base station, the MOB_MSSHO_RSP message includes information on the second adjacent base station 630, which is the target base station selected by the MSS600. In step 821, the serving base station 610 sends a HO_notification_confirm message to the second adjacent base station 630 before proceeding to step 823. In step 823, the serving base station 610 receives the HO_IND message from the MSS 600 before proceeding to step 825. In step 825, when the serving base station 610 receives the HO_IND message, it senses that the MSS600 has handed over to the second adjacent base station 630, breaks the link currently set up with the MSS600, and terminates its operation. ..
FIG. 9 is a flowchart showing an operation process of a serving base station that performs handover according to the second embodiment of the present invention. Prior to the description of FIG. 9, the first embodiment and the second embodiment of the present invention have the same basic handover process. However, it is different whether the MSS600 determines the target base station to be handed over by the MSS600 or the serving base station 610 determines. Therefore, the operating process of the serving base station 610 is basically the same as the operating process of the serving base station 610 described with reference to FIG. 8, except that the process of determining the target base station is different. That is, the operation process from step 911 to step 917 shown in FIG. 9 is the same as the operation step from step 811 to step 817 in FIG. 8, and the operation process from step 925 to step 929 in FIG. 9 is shown in FIG. It is the same as the operation process from step 821 to step 825 in 8.
In FIG. 9, since the MSS 600 does not select the target base station and the serving base station 610 selects the target base station as in FIG. 8, the serving base station 610 selects the first adjacent base station 620 in step 919. After receiving the MOB_MSSHO_RSP message containing the CINR results and / or Service Level Prediction of all pilot channel signals of the second adjacent base station 630 and the third adjacent base station 640, the process proceeds to step 921. In step 921, the serving base station 610 refers to the CINR results and / or Service Level Prediction of the pilot channel signals of the first adjacent base station 620 and the second adjacent base station 630 contained in the MOB_MSSHO_RSP message. After the MSS600 determines the target base station to be handed over as the second adjacent base station 630, the process proceeds to step 923. In step 923, the serving base station 610 inserts information about the above-determined target base station, that is, the second adjacent base station 630, into the MOB_BSHO_RSP message and transmits it to the MSS600.
FIG. 10 is a flowchart showing the operation process of the MSS that performs the handover according to the first embodiment of the present invention. Referring to FIG. 10, the MSS600 receives a DL_MAP message from the serving base station 610 in step 1011 to detect downlink information, and then proceeds to step 1013. In step 1013, the MSS600 receives the UL_MAP message from the serving base station 610, detects the uplink information, and proceeds to step 1015. The MSS600, which has detected the information on the downlink and the information on the uplink in this way, transmits / receives data from / to the serving base station 610 in step 1015, and proceeds to step 1017. In step 1017, the MSS600 checks to see if a MOB_BSHO_REQ message is received from the serving base station 610. As a result of the inspection, if the MOB_BSHO_REQ message is not received, the MSS600 returns to step 1011. However, if the MOB_BSHO_REQ message is received, the MSS600 proceeds to step 1019.
In step 1019, the MSS600 arranges the adjacent base stations contained in the MOB_BSHO_REQ message according to the Qos level priority, and then proceeds to step 1021. In step 1021, the MSS600 initializes the value of the variable i indicating the number of adjacent base stations to 0, and the variable indicating the number of adjacent base stations having a CINR exceeding a predetermined threshold CINR'. After initializing the value of Active_Count'to 0, proceed to step 1023. At step 1023, the MSS600 checks to see if the CINR of any i-th adjacent base station exceeds the threshold CINR. As a result of the inspection, if the CINR of the i-th neighboring base station does not exceed the above threshold CINR, the MSS 600 proceeds to step 1025. At step 1025, MSS600 increments the value of variable i by 1 (i = i + 1) and returns to step 1021.
If the CINR of the i-th neighboring base station exceeds the above threshold CINR, the MSS 600 proceeds to step 1027. At step 1027, the MSS600 increments the value of the variable'Active_Count' by 1 (Active_Count = Active_Count + 1) and proceeds to step 1029. In step 1029, the MSS600 checks whether the value of the variable'Active_Count'is greater than or equal to the value'Active_SET' indicating the number of adjacent base stations constituting the active set of the MSS600. As a result of the inspection, if the value of the variable'Active_Count'is smaller than the value'Active_SET' indicating the number of adjacent base stations constituting the active set of the MSS600, the MSS600 proceeds to step 1025.
On the other hand, if the value of the variable'Active_Count'is greater than the value of'Active_SET', MSS600 proceeds to step 1031. The above'Active_SET'is a value set to limit the number of target base stations. That is, when the value of'Active_SET'is 3 and the number of target base stations that can be handed over is 5, 3 target base stations are selected from the 5 target base stations. In step 1031, the MSS 600 determines the target base station among the adjacent base stations having a CINR exceeding the threshold CINR, that is, the second adjacent base station 630 is determined as the target base station, and the above determination is made. After sending an MSSHO_RSP message containing information for the target base station to the serving base station 610, the process proceeds to step 1033. At step 1033, the MSS 600 sends a HO_IND message to the serving base station 610 before proceeding to step 1035.
In step 1035, the MSS 600 changes the center frequency to the frequency of the target base station, i.e., the second adjacent base station 630, and then proceeds to step 1037. In step 1037, the MSS 600 receives a DL_MAP message from the second adjacent base station 630 to detect downlink information, and then proceeds to step 1039. At step 1039, the MSS600 receives the UL_MAP message from the second adjacent base station 630 to detect the uplink information and proceeds to step 1041. The MSS600, which has detected the information on the downlink and the information on the uplink in this way, transmits / receives data from / to the second adjacent base station 630 in step 1041 and ends the handover process. Of course, the MSS600 can perform a handover to another adjacent base station while transmitting / receiving data from / to the second adjacent base station 630. It should be noted that FIG. 10 shows only one handover process for convenience of explanation.
FIG. 11 is a flowchart showing the first operation process of the MSS that performs the handover according to the second embodiment of the present invention. Referring to FIG. 11, the operation from step 1111 to step 1117 shown in FIG. 11 is the same as the operation from step 1011 to step 1017 described in FIG. 10, and the operation from step 1125 to step 1133 shown in FIG. Since the operations up to are the same as the operations from step 1033 to step 1041 in FIG. 10, detailed description thereof will be omitted here.
First, if the inspection result in step 1117 shows that the MOB_BSHO_REQ message is received from the serving base station 610, the MSS 600 proceeds to step 1119. At step 1119, the MSS600 measures the CINR for the adjacent base station contained in the MOB_BSHO_REQ message before proceeding to step 1121. In step 1121, the MSS600 sends a MOB_MSSHO_RSP message containing the CINR result of the measured adjacent base station to the serving base station 610, and then proceeds to step 1123. In step 1123, the MSS600 proceeds to step 1125 after receiving the MOB_BSHO_RSP message from the serving base station 610. In step 1125, the MSS600 detects information about the handover target base station, ie, the second adjacent base station 630, contained in the MOB_BSHO_RSP message and sends a HO_IND message to the serving base station 610, after which it sends a HO_IND message to step 1127. Proceed to. The MSS600 can perform a handover to another adjacent base station while transmitting / receiving data from / to the second adjacent base station 630. It should be noted that in FIG. 11, for convenience of explanation, only one handover process is shown.
FIG. 12 is a flowchart showing a second operation process of the MSS that performs the handover according to the second embodiment of the present invention. Referring to FIG. 12, the operation from step 1211 to step 1229 shown in FIG. 12 is the same as the operation from step 1011 to step 1029 described with reference to FIG. 10, and step 1235 shown in FIG. Since the operation from to step 1243 is the same as the operation from step 1033 to step 1041 in FIG. 10, detailed description thereof will be omitted here.
First, in step 1231 the MSS600 sends a MOB_MSSHO_RSP message containing information for an adjacent base station having a CINR that exceeds the threshold CINR to the serving base station 610, and then proceeds to step 1233. In FIG. 11, the MSS600 sent a MOB_MSSHO_RSP message to the serving base station 610 containing the CINR results for all neighboring base stations that the MSS600 can hand over, but according to FIG. 12, all the neighboring base stations that the MSS600 can hand over Among them, the MOB_MSSHO_RSP message including the CINR result for only the adjacent base stations exceeding the threshold CINR is transmitted to the serving base station 610. In step 1233, the MSS600 receives a MOB_BSHO_RSP message from the serving base station 610 to detect the target base station information before proceeding to step 1235. The MSS600 can perform a handover to another adjacent base station while transmitting / receiving data from / to the second adjacent base station 630. It should be noted that in FIG. 12, for convenience of explanation, only one handover process is shown.
As described above, although specific embodiments have been described in the detailed description of the present invention, it is clear that various modifications are possible as long as they do not deviate from the scope of the present invention. Therefore, the scope of the present invention is not limited to the above-described embodiment, and should be defined by the description of the scope of claims and the equivalent of the description.
<figref num="1">It is a figure which showed the structure of the general IEEE 802.16e communication system.</figref><figref num="2">It is a figure which showed the structure of the downlink frame of a general IEEE 802.16e communication system.</figref><figref num="3">It is a figure which showed the structure of the uplink frame of a general IEEE 802.16e communication system.</figref><figref num="4">It is a signal flow diagram which showed the 1st range process between the base station of a general IEEE 802.16e communication system, and MSS.</figref><figref num="5">It is a signal flow diagram which showed the 2nd range process between a base station of a general IEEE 802.16e communication system and MSS.</figref><figref num="6">It is a signal flow diagram which showed the handover process by the request of the serving base station by 1st Embodiment of this invention.</figref><figref num="7">It is a signal flow diagram which showed the handover process by the request of the serving base station by the 2nd Embodiment of this invention.</figref><figref num="8">It is a flowchart which showed the operation process of the serving base station which performs the handover according to the 1st Embodiment of this invention.</figref><figref num="9">It is a flowchart which showed the operation process of the serving base station which performs the handover according to the 2nd Embodiment of this invention.</figref><figref num="10">It is a flowchart which showed the operation process of the MSS which performs the handover according to the 1st Embodiment of this invention.</figref><figref num="11">It is a flowchart which showed the 1st operation process of the MSS which performs the handover according to the 2nd Embodiment of this invention.</figref><figref num="12">It is a flowchart which showed the 2nd operation process of the MSS which performs the handover by the 2nd Embodiment of this invention.</figref>
Code description
600 mobile subscriber terminal 610 Serving base station 620 First adjacent base station 630 Second adjacent base station 640 Third adjacent base station
25 sheets
Sheet 1 Sheet 2 Sheet 3 Sheet 4 Sheet 5 Sheet 6 Sheet 7 Sheet 8 Sheet 9 Sheet 10 Sheet 11 Sheet 12 Sheet 13 Sheet 14 Sheet 15 Sheet 16 Sheet 17 Sheet 18 Sheet 19 Sheet 20 Sheet 21 Sheet 22 Sheet 23 Sheet 24 Sheet 25
Every citation, both waysCites: the store holds 2 of 3
| Document | Relation | Office |
|---|---|---|
| JP2002525938A | Cites | Japan |
| JP11075237A | Cites | Japan |
| SOHYUN KIM,JUNGJE SON,CHANGHOI KOO,"Overall HO procedures for IEEE 802.16",IEEE 802.16 Broadband Wireless Access Working Group,米国,2003年 9月 4日,pages 0-15. | Non-patent | – |
25 members in 9 offices
Priority claims9
| Document | Office | Kind | Date |
|---|---|---|---|
| 1020030078820 | Republic of Korea | – | |
| 20030078820 | Republic of Korea | A | |
| 20030078820 | Republic of Korea | A | |
| 2004002878 | Republic of Korea | W | |
| 2004002878 | Republic of Korea | W | |
| 2003200378820 | – | – | – |
| 2004002878 | – | – | – |
| KR20030078820 | – | – | – |
| WO2004KR02878 | – | – | – |
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| KR20050044220A | Republic of Korea | A | |
| US2005101328A1 | United States of America | A1 | |
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| WO2005046090A1 | World Intellectual Property Organization (WIPO) | A1 | |
| EP1530385A3 | European Patent Office (EPO) | A3 | |
| KR100651430B1 | Republic of Korea | B1 | |
| CN1871796A | China | A | |
| JP2007509527A | Japan | A | |
| RU2006119917A | Russian Federation | A | |
| US2008159235A1 | United States of America | A1 | |
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| RU2333604C2 | Russian Federation | C2 | |
| US7570618B2 | United States of America | B2 | |
| JP4459232B2This record | Japan | B2 | |
| EP2187689A1 | European Patent Office (EPO) | A1 | |
| CN1871796B | China | B | |
| CN101801050A | China | A | |
| US2011176515A1 | United States of America | A1 | |
| US8077673B2 | United States of America | B2 | |
| US8160026B2 | United States of America | B2 | |
| CA2540865C | Canada | C | |
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| EP2187689B1 | European Patent Office (EPO) | B1 |
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Numbers
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- 4459232
- Publication, DOCDB
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- Publication, EPODOC
- JP4459232B
- Application
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Titles2
- Japanese
- 広帯域無線接続通信システムにおけるハンドオーバーを行うシステム及び方法
- English
- Systems and methods for handover in a wideband wireless communication system
Classification
- CPC, 5
- H04W36/26
- H04W36/0085
- H04W36/08
- H04W36/22
- H04W36/304
- IPC, 6
- H04W36 26
- H04W40 34
- H04B7 26
- H04L45 851
- H04W36 08
- H04W36 38
