KR20050097811A - Method for release of point-to-multipoint radio mearer in mobile communication system - Google Patents

Abstract

The present invention relates to a point-to-multiple radio bearer release method for MBMS service in a mobile communication system. To this end, in the present invention, the wireless system transmits data of a specific MBMS service through a first point-to-multiple radio bearer, and transmits status information of a specific MBMS service through a second point-to-multiple radio bearer, and sets a first point-to-multiple radio bearer to set a specific MBMS. The wireless mobile terminal receiving the data of the service receives the status information through the second point-to-multiple radio bearer when the data is not received for a predetermined time, and releases the first point-to-multiple radio bearer based on the received status information. Decide As a result of checking the status information, the radio bearer for the specific MBMS service is not currently set in the wireless system, or the type of the radio bearer set in the wireless system for the specific MBMS service is point-to-point, or the session of the specific MBMS service is in progress. If not, or if a particular MBMS service is not currently available, the wireless mobile terminal releases the preset first point-to-point radio bearer.

Description

METHODO FOR RELEASE OF POINT-TO-MULTIPOINT RADIO MEARER IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a multicast or broadcast service (MBMS) in a mobile communication system, and more particularly, to a point-to-multiple radio bearer release method for an MBMS service.

1 is a diagram illustrating a network structure of a general UMTS (Universal Mobile Telecommunications System). The UMTS system is composed of a user equipment (UE), a UTMS Terrestrial Radio Access Network (UTRAN), and a core network (CN). The UTRAN consists of one or more Radio Network Sub-systems (RNS), each RNS including one Radio Network Controller (RNC) and one or more base stations (Node B) managed by the RNC. It consists of. One or more Cells are present in one Node B.

Figure 2 is a structure of a radio interface protocol (Radio Interface Protocol) between the terminal and the UTRAN based on the 3GPP radio access network standards. As shown in FIG. 2, the air interface protocol is horizontally composed of a physical layer, a data link layer, and a network layer, and vertically transmits data information. It is divided into a user plane for control plane and a control plane for control signal transmission.

In addition, the protocol layers of FIG. 2 are based on the lower three layers of the Open System Interconnection (OSI) reference model, which are well known in communication systems, and include L1 (first layer), L2 (second layer), and L3. (The third layer).

The physical layer, which is the first layer, provides an information transfer service to an upper layer by using a physical channel. The physical layer is connected to a higher medium access control layer through a transport channel. Data is transferred between the media access control layer and the physical layer through the transport channel, and data between different physical layers, that is, between the physical layer of the transmitting side and the receiving side, moves through the physical channel.

The medium access control (MAC) layer of the second layer provides a service to a radio link control (RLC) layer, which is a higher layer, through a logical channel. The RLC layer of the second layer supports reliable data transmission and performs segmentation and concatenation of an RLC Service Data Unit (SDU) from a higher layer. Can be.

The radio resource control (RRC) layer located at the bottom of the third layer is defined only in the control plane, and the configuration, re-configuration, and release of radio bearers (RBs) are performed. It is in charge of controlling logical channel, transport channel and physical channel related to Release. In this case, the RB means a service provided by the second layer for data transmission between the UE and the UTRAN, and in general, the RB is configured to define characteristics of a protocol layer and a channel necessary for providing a specific service, respectively. This refers to the process of setting specific parameters and operation methods.

Hereinafter, a multimedia broadcast / multicast service (MBMS) will be described in detail.

MBMS refers to a method of providing a streaming or background service to a plurality of terminals using a downlink-only MBMS bearer service. One MBMS service is composed of one or more sessions, and MBMS data is transmitted to a plurality of terminals through the MBMS bearer service only while the session is ongoing.

The UTRAN uses a radio bearer to provide MBMS bearer services to the terminal. Types of radio bearers used by the UTRAN include a point-to-point radio bearer and a point-to-multipoint radio bearer. The point-to-point radio bearer is a bi-directional radio bearer (bi-directional RB), and includes a logical channel dedicated traffic channel (DTCH), a transport channel dedicated channel (DCH), and a physical channel dedicated physical channel (DPCH) or physical channel SCCPCH (Secondary Common Control). Physical Channel). The point-to-multipoint radio bearer is a unidirectional downlink radio bearer (uni-directional downlink RB) and, as shown in FIG. 3, is composed of a logical channel MTMS (MBMS Traffic Channel), a transport channel FACH (Forward Access Channel), and a physical channel SCCPCH. The MTCH, which is the logical channel, is configured for each MBMS service provided to one cell and used to transmit user plane data of a specific MBMS service to a plurality of terminals.

The UTRAN providing the MBMS service transmits a control message related to the MBMS, that is, an RRC message related to the MBMS, to a plurality of terminals through the MCCH channel. The control message related to the MBMS includes a message indicating the MBMS service information and a message indicating the point-to-multiple radio bearer information. As shown in FIG. 3, the MCCH, which is a logical channel, is a point-to-multipoint downlink channel, and is mapped to a forward channel FACH, which is a physical channel Secondary Common Control Physical Channel (SCCPCH). Is mapped to. In this case, only one MCCH exists in one cell.

Accordingly, a terminal that wants to receive a specific MBMS service using a point-to-multiple radio bearer receives an RRC message including radio bearer information through an MCCH channel and then sets up a point-to-multiple radio bearer using the information. After configuring the point-to-multiple radio bearer, the UE continuously receives the physical channel SCCPCH to which the MTCH is mapped to obtain data of a specific MBMS service transmitted through the MTCH.

When one session of a specific MBMS service using a point-to-multiple radio bearer is terminated, the UTRAN transmits a message instructing release of the point-to-multiple radio bearer to terminals receiving the specific MBMS service through the MCCH channel. The UTRAN also releases the point-to-many radio bearer set in the RNC and Node B. Therefore, after receiving the message, the terminal releases the point-to-many radio bearer set up for the specific MBMS service.

As such, the terminals receiving the specific MBMS service by setting up the point-to-point radio bearer release the set point-to-point radio bearer according to the release message of the point-to-point radio bearer transmitted from the system. However, if the terminal does not receive the release message due to a poor wireless environment or an operation error, the terminal cannot determine when to release the set point-to-multiple radio bearer.

Therefore, if the terminal performs the release of the radio bearer in the temporary data stop state, it will not receive the data of the MBMS service transmitted after the temporary data stop. Further, if the terminal does not decide to release the radio bearer and does not release the radio bearer, the terminal wastes terminal resources because it must keep the point-to-multiple radio bearer. That is, in the prior art, the terminal cannot determine when to release the radio bearer due to the inability to distinguish between temporary data stop and release of the radio bearer. Therefore, the terminal cannot effectively control the maintenance and release of the radio bearer. Occurs.

Accordingly, an object of the present invention is to provide a radio bearer release method of a mobile communication system that can effectively control the maintenance and release of a point-to-multiple radio bearer.

Another object of the present invention is to determine the release of point-to-multiple radio bearers based on MBMS status information, i.e., status information of multicast or broadcast service, when data of MBMS service, that is, multicast or broadcast service, is not received for a predetermined time. To provide a radio bearer release method of a mobile communication system.

In an embodiment of the present invention for achieving the above object, a wireless system transmits data of a specific MBMS service to a wireless mobile terminal through a specific point-to-point radio bearer, and the wireless mobile terminal sets the point-to-multipoint radio bearer. And the data is received, and the wireless mobile terminal releases the preset point-to-multipoint radio bearer when no data is received for a predetermined time through the point-to-point radio bearer.

Preferably, the predetermined time corresponds to a time when the timer expires, and the timer is driven by a specific entity provided in the terminal.

Preferably, the specific entity is one of MAC, RLC and PDCP entities located in the second layer of the wireless protocol. The specific entity starts a timer after receiving one data packet, and if another data is not received until the timer expires, the specific entity notifies the RRC layer of expiration of the timer, and the RRC layer sends the second layer to the second layer. Instructs the release of the point-to-radio bearer.

In addition, in an embodiment of the present invention for achieving the above object, the wireless system transmits the data of the specific MBMS service and the status information through the second point-to-multiple radio bearer through the first point-to-point radio bearer, respectively, A wireless mobile terminal that sets up a radio bearer to receive data of a specific MBMS service receives the status information through a second point-to-multiple radio bearer when the data is not received for a predetermined time, and based on the received status information, Determines the release of the point-to-point radio bearer.

Preferably, the status information is included in a control message related to the MBMS, and is transmitted to the wireless mobile terminal through the MBMS control channel (MCCH).

Preferably, the status information is included in a message indicating MBMS service information or a message indicating point-to-multiple radio bearer information.

Preferably, the status information includes ID information of a specific MBMS service, information on whether a radio bearer for a specific MBMS service is set in a wireless system, and information indicating whether point-to-multipoint or point-to-point when the radio bearer is set in a wireless system. Contains one or more pieces of information.

Preferably, the wireless mobile station checks the status information, and as a result, the radio bearer is not currently set in the wireless system, the type of the radio bearer in the current wireless system is point-to-point, the session of the specific MBMS service is not in progress, or Release the point-to-many radio bearer if a particular MBMS service is not currently available.

The present invention is implemented in a mobile communication system such as a universal mobile telecommunications system (UMTS) developed by 3GPP. However, the present invention can also be applied to communication systems operating according to other standards. Hereinafter, preferred embodiments of the present invention will be described in detail.

The present invention proposes a method for effectively releasing a point-to-multiple radio bearer by checking a state of the MBMS service when the data is not available for a certain period of time.

In the present invention, in order to control the radio bearer of the terminal, the wireless system transmits a data unit of a specific MBMS service to the terminal through a specific point-to-multiple radio bearer, and the terminal establishes a point-to-multiple radio bearer. The data unit is then received via the point-to-multipoint radio bearer. The terminal triggers a timer when one data unit is received, and then releases the set point-to-multipoint radio bearer when another data unit is not received until the timer expires.

If another data unit is received before the timer expires, the terminal initializes the timer and then drives the timer again. The timer for the one data unit is driven by a specific entity of the terminal. Preferably, the entity is located in the second layer of the wireless protocol and is a MAC or RLC or PDCP entity. If another data is not received until the timer expires, the entity notifies the RRC of expiration of the timer, and the RRC notified of the expiration of the timer executes the release of the point-to-multiple radio bearer set in the terminal.

In addition, in the present invention, in order to control the radio bearer of the terminal, a wireless system transmits a data unit of a specific MBMS service through a specific point-to-multiple radio bearer, and status information of the MBMS service through another point-to-multiple radio bearer. information) to the terminal. Accordingly, the terminal sets a point-to-point radio bearer to receive a data unit through the point-to-point radio bearer, and if the data unit is not received for a specific time, receives the state information through the another point-to-point radio bearer. The release of the point-to-multipoint radio bearer is determined according to the received state information.

In this case, the specific entity of the terminal detects whether a data unit is received for a specific time through the radio bearer. Preferably, the specific entity is a MAC or RLC or PDCP entity located in the second layer of the wireless protocol. If the entity detects that it has not received a data unit for a certain time, it notifies the RRC of the detection.

Accordingly, the RRC notified of the detection receives the status information through the another point-to-many radio bearer. If the received state information indicates that a session of the MBMS service is not currently in progress, or indicates that the wireless system does not provide the point-to-multiple radio bearer, the terminal releases the point-to-multiple radio bearer. Decide

4 is a flowchart illustrating a method of detecting a data unit by a terminal.

In particular, FIG. 4 shows the reception of a data unit for a specific time while the L2 entity (PDCP or RLC or MAC entity) located in the second layer of the radio protocol of the terminal receives a data unit of a specific MBMS service through a specific point-to-multiple radio bearer. It is used to determine whether or not.

As shown in FIG. 4, the terminal L2 entity sets up a point-to-multiple radio bearer according to a command of the terminal RRC, and receives and stores a threshold count value T_PTM from the terminal RRC (S10). When the storing of the T_PTM is completed, the terminal L2 entity initializes the count value of the timer T and then drives the timer T (S11 and S12).

The terminal L2 entity determines whether there is a data unit received through the point-to-multiple radio bearer in units of transmission time interval (TTI) (S12). As a result of the check, if there is a data unit received during one TTI, the terminal L2 entity performs step S11 again.

On the other hand, if there is no data unit received during one TTI, the terminal L2 entity compares the count value T of the current timer with the previously stored threshold count value T_PTM (S14) and checks whether the timer has expired. At this time, the terminal L2 entity determines that the timer has expired when T is larger than T_PTM, and performs step S13 again when T is smaller than T_PTM.

As a result of the check, when it is determined that the timer has expired, the UE L2 entity notifies the UE RRC that the timer has expired (S15).

5 is a diagram illustrating a method of releasing a point-to-multiple radio bearer according to the present invention.

First, the terminal L2 entity sets up a point-to-multiple radio bearer for receiving a data unit of a specific MBMS service, and then receives the data unit through the set point-to-multiple radio bearer (S20).

As described in FIG. 4, when the data unit is not received for a specific time, that is, when the timer expires, the UE L2 entity notifies the UE RRC of the timer expiration (S21).

Upon receiving the timer expiration, the terminal RRC receives MBMS status information from the wireless system to determine the status of the specific MBMS service (S22). Preferably, the MBMS status information includes ID information of a specific MBMS service, whether a radio bearer for a specific MBMS service is set in a wireless system, and whether the point-to-point or point-to-point is pointed when the radio bearer is set in a wireless system. Indicates. In addition, the MBMS status information indicates whether a session of a specific MBMS service is currently in progress or whether a specific MBMS service is currently available. More specifically, the MBMS status information is included in a control message related to the MBMS, and is transmitted from the wireless system to the terminal through the MBMS Control Channel (MCCH). Preferably, the MBMS status information is included in a message indicating MBMS service information or a message indicating point-to-multiple radio bearer information.

As a result of determining the state of the specific MBMS service, the current radio bearer is not configured in the wireless system, the type of the wireless bearer currently configured in the wireless system is point-to-point, the session of the specific MBMS service is not in progress, or the specific MBMS service is If not currently available, the terminal RRC instructs the terminal L2 entity to release the set point-to-multiple radio bearer (S23).

Accordingly, the terminal L2 entity releases the point-to-multiple radio bearer set in step S20 according to the command of the terminal RRC (S24).

In addition, in FIG. 5, the terminal RRC may release the point-to-multiple radio bearer without performing step S22, that is, without performing the step of receiving MBMS status information. That is, when the timer expiration is notified from the terminal L2 entity, the terminal RRC immediately instructs the terminal L2 entity to release the point-to-multiple radio bearer set in step S20.

As described above, according to the present invention, when the wireless mobile terminal receiving data of a specific MBMS service through the point-to-multiple radio bearer fails to receive data for a predetermined time, it determines the release of the point-to-multiple radio bearer by checking the status of the MBMS service. As a result, it is possible to effectively control the maintenance and release of the point-to-multiple radio bearer by the terminal.

In addition, although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely exemplary and will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. . Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

1 is a diagram illustrating a network structure of a general UMTS.

2 is a diagram showing the structure of a radio interface protocol between a UE and a UTRAN based on the 3GPP radio access network standard;

3 is a diagram illustrating an example of channel mapping for an MBMS on a terminal side.

4 is a flowchart illustrating a data unit detection method of a terminal according to the present invention.

5 illustrates a method of releasing a point-to-multiple radio bearer in accordance with the present invention.

Claims (15)

In a mobile communication system for transmitting one or more MBMS services from a wireless system to a wireless mobile terminal, The wireless system transmits data of a specific MBMS service to a wireless mobile terminal through a specific point-to-multiple radio bearer, and the wireless mobile terminal sets up the point-to-multiple radio bearer to receive the data, and for a predetermined time through a point-to-multiple radio bearer. And if no other data is received during the point-to-multipoint radio bearer release. The method of claim 1, wherein the wireless mobile terminal A method of releasing a point-to-multiple radio bearer, wherein the preset point-to-multiple radio bearer is released when one data is not received for a predetermined time. The method of claim 1, wherein the predetermined time Point-to-many radio bearer release method, characterized in that corresponding to the expiration time of the timer. The method of claim 3, wherein the timer is Point-to-multipoint radio bearer release method, characterized in that driven by a specific entity provided in the terminal. The method of claim 4, wherein the specific entity is Point to multi-radio bearer release method characterized in that one of the MAC, RLC and PDCP entities located in the second layer of the radio protocol. The method of claim 5, wherein the specific entity is And a timer for one data, if no other data is received until the timer expires, notifying the expiration of the timer to the RRC layer. In a mobile communication system for transmitting one or more MBMS services from a wireless system to a wireless mobile terminal, The wireless system transmits data of a specific MBMS service through a first point-to-point radio bearer and a state information through a second point-to-point radio bearer, respectively, and sets a first point-to-many radio bearer to receive data of a specific MBMS service. When the data is not received for a predetermined time, the status information is received through a second point-to-multiple radio bearer, and the point-to-multiple radio bearer release is determined based on the received status information. Way. The method of claim 7, wherein the status information Point-to-many radio bearer release method, characterized in that included in the control message related to the MBMS. The method of claim 7, wherein the status information A point-to-multiple radio bearer release method, characterized in that the transmission to the wireless mobile terminal through the MBMS control channel (MCCH). The method of claim 7, wherein the status information A point-to-multipoint radio bearer release method, characterized in that it is included in a message indicating the MBMS service information or a message indicating point-to-multiple radio bearer information. The method of claim 7, wherein the status information A point-to-many radio bearer release method characterized by indicating whether ID information of a specific MBMS service, a radio bearer for a specific MBMS service is set, and whether it is point-to-point or point-to-point when the radio bearer is set. The method of claim 7, wherein the status information A point-to-many radio bearer release method, which indicates whether a session of a particular MBMS service is currently in progress or whether a particular MBMS service is currently available. The method of claim 7, wherein the status information Point-to-many radio bearer release method characterized in that the check in the RRC (Radio Resource Control) layer. The method of claim 7, wherein the wireless mobile terminal As a result of checking the status information, if the current radio bearer is not configured, the type of the current radio bearer is point-to-point, the session of the specific MBMS service is not in progress, or the specific MBMS service is not currently available, the point-to-point radio bearer Point-to-multipoint radio bearer release method, characterized in that for releasing. 8. The method of claim 7, wherein if no data is received during the predetermined time, the RRC layer of the wireless mobile terminal receives the status information from a wireless system.