Method of transmitting/receiving a paging message in a wireless communication system

Method for transmitting/receiving a paging message in wireless communication system

The present invention generally relates to a wireless communication system, and particularly relates to a method for transmitting/receiving a paging message in a wireless communication system.

When a network calls a user equipment (UE) or multiple UEs, a paging procedure in a mobile communication system is required. In the "Universal Mobile Telecommunications System (UMTS)", "Paging Type 1" and "Paging Type 2" messages are used.

When a UE is in an idle state, a Cell_PCH or a URA_PCH, the "Paging Type 1" message is used. A core network (CN) calls a UE in an idle state to establish a signaling connection, or requests to establish a call or session with the UE. A UE under a Cell_PCH or URA_PCH can be paged to perform a cell update operation or URA (UTRAN registration area) update procedure. In addition, the "Paging Type 1" message can be used in the UTRAN to request a UE to read updated system information. All UEs in a cell will be paged, because the updated system information is extremely important for all UEs. The UE identification data is included in a paging message to identify a UE. This is a high-level UE identification data, which can be like an IMSI (International Mobile Subscriber Identity Data) for a UE in an idle state , TMSI (temporary mobile user identification data) or P-TMSI (packet temporary mobile user identification data), which can be a U-RNTI (UTRAN radio network temporary identification for a UE in a connected mode) material).

When a UE under Cell_DCH or Cell FACH is additionally paging through a pre-established RRC connection, the "Paging Type 2" message is used. Dedicated paging can be performed to a specific UE, because the pre-established RRC connection is used.

The paging message corresponds to a paging instruction (PI) transmitted on a transmission channel PCH (paging channel). When a UE is paged, the UTRAN sends the paging indication to the UE on a paging indication channel (PICH), thereby notifying the UE that a paging message will be sent. After a pre-established time period has elapsed after receiving the paging instruction, the UE can receive the paging message on the PCH.

In related arts, the radio resources used to transmit the paging message are fixed. For example, the paging instruction is sent on a PICH with an expansion factor (SF) of 256, and the PCH containing a paging message is sent on the S-CCPCH in UMTS. When paging messages are sent through these fixed radio resources, the network cannot be flexible in the scheduling of data transmission operations, so it becomes difficult to adapt to changes in the radio environment. In addition, when paging a UE at a cell boundary, a paging procedure cannot be performed smoothly, because the reception error increases as the distance between the UE and an eNB increases.

Therefore, the present invention is directed to a method for transmitting/receiving a paging message in a wireless communication network, which can greatly alleviate one or more problems caused by the limitations and shortcomings of related technologies.

An object of the present invention is to provide a method for transmitting/receiving a paging message, in which a paging message is dynamically allocated on a radio resource according to a paging instruction, and the same paging message sent from multiple cells will be UEs are merged, so the scheduler can have higher scheduling flexibility, and at the same time, it can receive paging messages more accurately near the edge of a cell.

Other characteristics and advantages of the present invention will be partly in the following description and partly obvious from the description, or can be stated in a manner known to implement the present invention. The various objects and other advantages of the present invention can be realized and obtained by the structure specified in the description and the scope of the patent application, as well as the accompanying drawings.

In order to achieve these and other advantages, and in accordance with the purpose of the present invention, that is, as specifically implemented and broadly described, the present invention is based on receiving a paging message at a user equipment (UE) in a wireless communication system The method is specifically implemented, the method includes receiving paging instruction information from a network, which includes UE identification information, and schedule information for a paging channel (PCH) on which a paging message is transmitted, the schedule information Contains configuration information of a time-frequency range through which the paging message is sent; when the UE identification information is equal to the UE's identification data, the paging instruction information is obtained; and through the paging instruction information The indicated time-frequency range, the paging message is received from the network.

According to another embodiment of the present invention, a method for transmitting a paging message to a user equipment (UE) in a wireless communication system, the method includes transmitting paging instruction information to the UE, which includes a UE Identification information, and schedule information for a paging channel (PCH) on which a paging message is sent. The schedule information contains configuration information for a time-frequency range through which the paging message is sent; and From the time-frequency range indicated by the paging instruction information, the paging message is sent.

According to another embodiment of the present invention, a method for receiving a paging message at a user equipment (UE) in a wireless communication system, the method includes receiving paging instruction information from a network, which includes a UE Identification information, and schedule information for a paging channel (PCH) on which a paging message is transmitted; when the UE identification information is equal to the UE's identification data, obtain the paging instruction information; and by merging from the plural Multiple paging channels of each cell use the paging instruction information to receive a paging message.

According to another embodiment of the present invention, a method for receiving at least one paging message on a paging channel, the method includes receiving a paging instruction on an L1/L2 control signal; checking whether there is a corresponding paging instruction in the paging instruction A short identification data of a user equipment (UE); and if the short identification data does exist, a paging message with a long identification data is received on a radio resource indicated by the paging instruction.

Now, reference will be made in detail to various preferred embodiments of the present invention, and these examples are described in the accompanying drawings.

Figure 1 is a block diagram of the network structure of E-UMTS (Evolved Global Mobile Telecommunications System), and the technical features of the present invention can be applied to this. E-UMTS is a system evolved from traditional UMTS, and 3GPP ("Third Generation Partnership Project") is currently responsible for its basic standardization operations. The E-UMTS can also be referred to as an LTE ("Long Term Evolution") system.

Referring now to Figure 1, an E-UMTS network contains a user equipment (hereinafter referred to as UE), a base station (hereinafter referred to as eNode B or eNB), and a device placed in the E-UMTS network An access gateway (hereinafter referred to as aGW) connected to an external network at the end. The aGW can be divided into one for handling user traffic and one for handling and controlling traffic. The first aGW, which is used to handle new user traffic, can communicate with the second AG, which is used to handle and control traffic, through a new interface. An eNode-B may contain at least one cell. A first interface for transmitting user traffic or a second interface for transmitting control traffic can be located between multiple eNode-Bs. The CN contains the aGW and a plurality of nodes for registering users of "User Equipment (UE)". If necessary, another interface for distinguishing the E-UTRAN and the CN can also be applied to the LTE network. The aGW can manage the mobility of a UE by a tracking area (TA) unit. A TA contains multiple cells. When a UE moves from one TA to another TA, the UE notifies the aGW of these TA changes. The eNode-B contains at least one cell.

Figure 2 is a schematic diagram, which illustrates an E-UTRAN protocol structure. In Figure 2, the shaded portion represents a functional item for control, and the non-shaded portion represents a functional item for user.

According to the three lower levels of the OSI (Open System Interconnection) reference model known in the communication system industry, the radio interface protocol layer between a UE and a network can be classified into a first layer L1 and a second layer. Layer L2 and a third layer L3. A physical layer belonging to the first layer L1 can use a physical channel to provide information transmission services. A radio resource control (hereinafter referred to as RRC) layer located at the third layer plays an important role in controlling the radio resources between the UE and the network. In this regard, the RRC layer can be used to exchange RRC messages between the UE and the network. The RRC layer can be located at multiple network nodes including an eNode B, an AG, etc., or at the node B or the AG.

Figures 3A and 3B are respectively the control-oriented and user-oriented architecture diagrams of the radio interface protocol between UE (User Equipment) and UTRAN (UMTS Terrestrial Radio Access Network) based on the 3GPP radio access network standard. Referring to Figure 3A, a radio interface protocol vertically includes a physical layer, a data link layer, and a network layer, and horizontally includes a user-oriented data information transmission and a signal transmission Control oriented. According to the three lower levels of the Open System Interconnection (OSI) standard model well known in the communication system industry, the protocol layers in Figure 3A can be classified into L1 (layer 1), L2 (layer 2) and L3 (Level 3).

The following will explain the individual levels of the radio protocol control shown in Figure 3A and the radio protocol users shown in Figure 3B.

First, the physical layer, such as the first layer, can use physical channels to provide information transmission services to an upper layer. The physical layer (PHY) is connected to a media access control (hereinafter referred to as MAC) layer on the physical layer through a transmission channel. The transmission channels can be used to transmit data between the media access control layer and the physical layer. In addition, data can be transmitted between different physical layers through these physical channels, and especially between a physical layer on a transmitting side and another physical layer on a receiving side. One of the downlink physical channels of the E-UMTS is modulated in accordance with an orthogonal frequency division multiplexing (OFDM) law, and uses time and frequency channels as radio resources.

The media access control (hereinafter referred to as MAC) layer of the second layer can provide services to the radio link control (hereinafter referred to as RLC) layer on the MAC layer through logical channels. The RLC layer of the second layer supports reliable data transmission operations. In order to effectively transmit IP packets (i.e., IPv4 or IPv6) during a radio communication period with a narrow bandwidth, the PDCP layer of the second layer (L2) can perform header compression operations, thereby reducing It is necessary to control the size of the header of a very large IP packet of information.

A radio resource control (hereinafter referred to as "RRC") layer located at the lowest part of the third layer is only defined in the control plane and is related to the radio bearer (hereinafter referred to as It is related to the configuration setting, reconfiguration setting and release operation of RB). In this case, the RB refers to a service provided by the second layer for data transmission between the UE and the UTRAN.

Since the downlink transmission channel loads data from a network to a UE, there will be a broadcast frequency (BCH) carrying system information, and a downlink shared channel ( SCH). The downlink link SCH or an additional multiple broadcast channel (MCH) can be used to transmit downlink multicast or broadcast service traffic or control messages. At the same time, because the uplink transmission channel loads data from a UE to a network, there will be a random access channel (RACH) that carries an initial control message, and an uplink that carries user traffic or control messages. Connect the shared channel (UL-SCH).

In the E-UMTS system, an OFDM is used on the downlink link, and a single carrier frequency division multiple access (SC-FDMA) is used on the uplink link. The OFDM law using multiple carriers configures radio resources in units of multiple subcarriers, including a set of subcarriers, and uses an orthogonal frequency division multiple access (OFDMA) as an access rule.

The physical layer of an OFDM or OFDMA law can divide the active subcarriers into a plurality of groups, and transmit each group to a different receiving side. The radio resource allocated to each UE is defined as a time-frequency range on a two-dimensional sphere, which contains continuous subcarriers on a frequency axis and multiple symbols on a time axis. A time-frequency range within the OFDM or OFDMA law is a rectangular form segmented by time and frequency coordinates. One or more time-frequency ranges can be allocated to an uplink link for a UE, and an eNB can transmit one or more time-frequency ranges to a UE. In order to define a time-frequency range on the two-dimensional sphere, the number of the OFDM symbols and the sub-carriers starting from a point with a displacement from a reference point should be given.

The E-UMTS uses a 10 ms radio frame, which contains 20 sub-frames. That is, a sub-frame has a length of 0.5ms. A resource block contains one subframe and twelve subcarriers, each of which is 15KHz. A subframe contains a plurality of OFDM symbols, and part of the plurality of OFDM symbols can be used for L1/2 control information.

Figure 4 is a schematic diagram illustrating the structure of a physical channel in the E-UMTS. In Figure 4, a sub-frame contains an L1/2 control information transmission range (the shaded part) and a data transmission range (the non-shaded part).

Figure 5 is a schematic diagram illustrating a sub-frame according to a preferred embodiment of the present invention.

Referring now to Figure 5, a Discontinuous Reception (DRX) rule is applied to a UE in an idle mode or in an RRC connected state. The UE will wake up in a paging situation, which is predefined by system information from an E-UTRAN in a DRX cycle, and monitors whether a paging message is sent to the UE. In Figure 5, a DRX cycle contains five sub-frames, and the paging situation for the UE starts in the first sub-frame. The UE receives an L1/2 control information transmission range, and checks whether there is paging instruction information for the UE.

The paging instruction information contains UE identification information and information related to radio resources, that is, the time-frequency range for transmitting a paging message. When it is learned that the UE identification information in the paging instruction information is equivalent to the UE identification data of the UE, the UE receives the paging message on a paging channel (PCH) in the time-frequency range indicated by the paging instruction information .

The paging procedure of a UE in an idle mode and the DRX procedure of a UE in an RRC connected mode should be different. Table 1 describes the differences between the paging procedure and the DRX procedure.

<tables><img file="TW200735680A_D0001.tif" /></tables>

The paging procedure is initiated by an aGW to find the cell location of a UE in a tracking area (TA) and efficiently manage battery consumption. The paging procedure is applied to a UE in an idle mode. Since the UE in the idle mode does not have short UE identification data configured by a cell, a long UE identification data, such as IMSI or TMSI, etc., is included in the paging message.

The DRX procedure is executed by an eNB for a UE connected via RRC, so as to save the battery power of the UE. The DRX procedure can be applied when the uplink and downlink traffic are temporarily inactive. Since the RRC connected UE has short UE identification data configured by one song and one cell, such as C-RNTI (Cellular Radio Network Temporary Identification Data), the eNB can incorporate the short UE identification data in L1 /2 control information to wake up the UE connected via RRC.

In the case of the DRX procedure, a short UE identification data with a length equal to or less than 16 bits can be simply included in an L1/2 control channel. On the other hand, a paging message with a long UE identification data cannot be included in the L1/2 control information. The paging instruction information containing the short UE identification data can be included in the L1/2 control information or in a paging instruction channel (PICH).

In a preferred embodiment of the present invention, a UE in an idle mode uses a long UE identification data to monitor a paging channel (PCH). A UE connected via RRC can use a short UE identification data to monitor the L1/2 control information in a DRX cycle. If the UE connected via RRC in the DRX mode is scheduled, an eNB will insert the short UE identification data into the L1/2 control information containing the scheduling information with a predefined cycle. If the UE connected via RRC in the DRX mode is not scheduled, the eNB will not insert the UE's identification data into the L1/2 control information.

In a preferred embodiment of the present invention, an eNB schedules a paging channel (PCH) and a downstream link shared channel (DLSCH) at a UE-specific paging situation within each paging DRX cycle . The paging instruction information informs the UE whether a paging message for the UE is scheduled in the paging situation. The paging instruction information contains information related to the configured time-frequency range for paging messages, such as SCH scheduling processing.

The paging instruction information can be transmitted by a frequency hopping rule for frequency diversity. For example, the paging instruction information can be transmitted on different subcarriers in different time intervals, that is, different paging situations. Hopping information, that is, how to transmit the paging instruction information on different subcarriers in different paging situations, is included in the system information in a cell for transmission.

In a preferred embodiment of the present invention, the paging instruction information for a UE in the idle mode and the UE in the RRC connection mode can be included in the L1/2 control channel to use a short UE identification data is transmitted. In this case, regardless of the status of the UE, the UE will monitor the L1/2 channel.

Figures 6A and 6B are schematic diagrams illustrating another preferred embodiment of the present invention. A paging message is sent on a paging channel (PCH) in a subframe, but the paging instruction information in the specific embodiment shown in FIGS. 6A and 6B is not sent. In Figure 6A, the paging message is transmitted through a data transmission range without the paging instruction information, and the L1/2 control information is not transmitted in this range. A UE obtains information about a time-frequency range, and the paging channel (PCH) is transmitted through this range, and then uses the time-frequency information on the paging channel (PCH) to receive the paging message.

In Figure 6B, the paging message (PCH) is transmitted within the transmission range of the L1/2 control information, and there is no paging instruction information. A UE also obtains information about a time-frequency range, and the paging channel (PCH) is transmitted through this range, and then uses the time-frequency information on the paging channel (PCH) to receive the paging message.

Figures 7A and 7B are schematic diagrams illustrating another preferred embodiment of the present invention. A UE at a cell boundary area can use a merging rule to optimize the reception of a paging message and/or paging instruction information. Each cell sends an equivalent paging message and/or paging instruction information to the UE. The merger rule can be classified into a soft merger rule and a selective merger rule. Figures 7A and 7B respectively illustrate specific embodiments based on the soft merger rule and the selective merger rule.

Referring now to Figure 7A, in the case of the soft merger rule, the physical layer (layer 1) of a UE receives multiple paging messages from a plurality of cells contained in a tracking area (TA), and the Wait for paging messages to merge. Through a media access control (MAC) layer, the data merged by the physical layer is sent to a higher layer. The UE can combine the paging instruction information sent from a plurality of cells by the soft combination rule.

Referring now to Figure 7B, in the case of the selective merging rule, the physical layer (layer 1) of the UE receives the paging channel (PCH) from a plurality of cells respectively. The second layer, such as the MAC layer of the UE, combines the paging channels transmitted from the physical layer, and then transmits the combined data to the upper layer.

A cell can be contained in a plurality of tracking areas (TA). In this case, it is necessary to configure multiple paging control channels (PCCH) and paging channels (PCH) in the cell. That is, a paging control channel and a paging channel are configured for each tracking area. Therefore, the UE needs to select a PCCH and a PCH among a plurality of PCCHs and PCHs according to the tracking area, and receive the selected PCCH and PCH.

In particular, in the case of the selective merging process, an aGW needs to provide the L2 sequence number for the PCH, so as to support the selective merging process in the second layer of the UE. Therefore, different tracking areas require different serial numbers. The serial number can be added to the data unit of a paging message or a paging message itself. When the UE receives a paging channel (PCH), the second layer of the UE arranges the data unit or the paging message received on the PCH based on the sequence number. If the second layer of the UE finds a duplicate data unit or paging message with the same sequence number, the second layer of the UE selects only one of the correctly received ones, sends it to the upper layer, and discards the other One.

Or alternatively, the UE can combine multiple cells included in an eNB to receive a paging channel (PCH). The system information can be used to transmit information related to the cells that can be combined to receive paging information or paging instruction information from the eNB signal to the UE. At the same time, in the system information, information about whether the paging message or paging instruction information can be combined in a cell can be transmitted from the eNB signal to the UE.

When a cell provides a wider bandwidth than a UE, the UE should select which part of the bandwidth the UE needs to receive, so as to find its own paging message. For example, if the cell provides 20 MHz, but the UE is only 10 MHz, the UE should select which 10 MHz the UE needs to receive. In a specific embodiment of the present invention, the UE selects based on its UE identification data. In particular, the UE can select which part of the bandwidth the UE should receive based on its long UE identification data, such as the TMSI or IMSI configured by the aGW. At the same time, the UE can select which paging situation the UE should monitor in a UE-specific DRX cycle based on its long UE identification data, such as the TMSI or IMSI configured by the aGW.

Although the present invention has been described and illustrated with reference to its preferred embodiments, those skilled in the art should understand that various modifications and changes can be made without departing from the spirit and scope of the present invention. Therefore, the present invention intends to cover various modifications and changes that fall within the scope of the patent application filed later in the present invention and its equality.

<u style="single"><b>Industry applicability</b></u>

The present invention is suitable for wireless communication systems such as wireless Internet, mobile communication systems and so on.

The accompanying drawings are incorporated for further understanding of the present invention, and are incorporated to form a part of this application. These drawings illustrate the specific embodiment(s) of the present invention and are explained in conjunction with the detailed description. Principles of the invention.

Among the various diagrams: Figure 1 is a block diagram of the network structure of E-UMTS (Evolved Global Mobile Telecommunications System); Figure 2 is a schematic diagram illustrating the protocol architecture of an E-UTRAN; Figure 3A Figures and 3B are respectively the control-oriented and user-oriented architecture diagrams of the radio interface protocol between UE (User Equipment) and UTRAN (UMTS Terrestrial Radio Access Network) according to the 3GPP radio access network standard; Figure is a schematic diagram, which illustrates the structure of a physical channel in the E-UMTS; Figure 5 is a schematic diagram, which illustrates a sub-frame according to a preferred embodiment of the present invention; Figures 6A and 6B A schematic diagram for explaining another preferred embodiment of the present invention; and FIGS. 7A and 7B are schematic diagrams for explaining another preferred embodiment of the present invention.