KR101066319B1 - Method for serving broadcast service in a mobile communication system - Google Patents

Abstract

The present invention provides a multimedia broadcast / multicast service (MBMS) for providing the same service to a plurality of terminals or a service desired by the plurality of terminals in a mobile communication system using a code division multiple access system. A session message for which a service packet radio service support node (SGSN) has a list for a plurality of radio network controllers (RNCs) located in a routing area and informs the session start of the MBMS service (Session start). ) Is to provide a method for checking whether or not to transmit. According to the present invention, the RNCs receiving the session message from the SGSN efficiently maintain and operate an MBMS service context for supporting mobility of a given terminal.

MBMS, SGSN, Session Start, MCCH, UE Mobility, MBMS SERVICE AVAILABILITY

Description

Broadcasting service providing method in mobile communication system {METHOD FOR SERVING BROADCAST SERVICE IN A MOBILE COMMUNICATION SYSTEM}

1 is a diagram illustrating a structure of a 3GPP mobile communication network for a multicast multimedia broadcasting service to which the present invention is applied.

2 is a diagram illustrating a procedure for a multicast multimedia broadcasting service to which the present invention is applied.

3 illustrates a problem when sending a session start message in a manner currently proposed in the 3GPP standard.

4 is a diagram illustrating a process of transmitting a session start message newly proposed according to the present invention.

The present invention relates to a multimedia broadcast / multicast service (hereinafter referred to as MBMS). In particular, a service packet radio service support node (SGSN) transmits a session start message indicating the start of the MBMS service. In providing a method.

The MBMS refers to a service for transmitting the same multimedia data to a plurality of receivers through a wireless network.

First, FIG. 1 is a diagram illustrating a structure of a 3GPP mobile communication network for a multicast multimedia broadcasting service to which the present invention is applied.

Referring to FIG. 1, an example in which the MBMS can be applied to a wireless communication network is illustrated. In addition, FIG.

Terminals 101, 102, 103, 104, 105, 106, 107 and 108 of FIG. 1 refer to user equipments capable of receiving the MBMS. Cell 1, Cell 2, and Cell 3 of 111, 112, and 113 refer to a cell area of a base station where the UEs are located. Node B of 121 of FIG. 1 refers to a base station transmitting MBMS to UEs belonging to Node B of 121. A radio network controller (hereinafter referred to as 'RNC') of 131 indicates a base station controller that controls a plurality of Node Bs. The RNC of 131 selectively transmits multimedia data provided through the MBMS to specific Node Bs supporting or transmitting the MBMS, and the Node B of the 121 and 101, to provide the MBMS. It controls the radio channels established between the UEs of 102, 103, 104, 105, 106, 107, and 108.

The RNC of 131 of FIG. 1 and Node B of 121 under control of the RNC, Cell 1 of 111, Cell 2 of 111, and Cell 3 of 113 within Node B of 121 are UMTS Radio Access Networks. The UTRAN serves to connect the UEs 101, 102, 103, 104, 105, 106, 107, and 108 to a core network (hereinafter referred to as CN). do.

A serving packet wireless service support node (hereinafter referred to as 'SGSN') of 141 serves to control MBMS related services of respective subscribers. Typical examples include managing service billing data of each subscriber and selectively transmitting multimedia data to a specific RNC. The Home Location Register (HLR) of the 151 is connected with the SGSN of the 141 to authenticate a subscriber. A gateway packet wireless service support node (hereinafter referred to as 'GGSN') of 161 provides MBMS data to be supplied to the UEs with 181 BM-SC (Broadcast / Multicast Service Center) and 171 BG (Border Gateway). Received from the 191 content providers (Contents Provider) and the 192, 193 Multicast Broadcast Source and transmits to the SGSN of the 141. In addition, it manages the movement of each UE, and serves to manage the quality of service for the MBMS serviced by the UE. The BG of 171 receives MBMS data from 192 Multicast Broadcast sources in a network not currently managed by the service provider and transmits the MBMS data to the GGSN of 161. The BM-SC of 181 receives MBMS data from a content provider and delivers the MBMS data to the GGSN of 161. In addition, the authentication of the content provider, MBMS service quality determination, error correction function for MBMS data loss, charges for the Contents Provider and serves as the MBMS announcement currently being serviced for the UE. The Contents Provider of 191 and the Multicast Broadcast source of 192,193 indicate a source of MBMS data transmission.

The MBMS data stream is transmitted from the 191 content provider via the 181 BM-SC or from the 192 Multicast Broadcast Source to the 171 BG or directly from the 193 Multicast Broadcast Source to the 161 GGSN, 141. It is delivered to UEs of 101, 102, 103, 104, 105, 106, 107, and 108 via SGSN, 131, RNC, 121, Node B, 111, 112, and 113 Cell.

Although not shown in FIG. 1, a plurality of SGSNs and a plurality of RNCs connected to each SGSN may exist for one MBMS. In addition, the SGSN is an RNC, and the RNC needs to perform selective data transmission to Node B. For this purpose, a list of nodes (SGSG list in RSN, Node B list in RNC), etc., is stored. do.

2 is a diagram illustrating a procedure for a multicast multimedia broadcasting service to which the present invention is applied.

Referring to FIG. 2, a process of providing an MBMS service in a specific cell is illustrated. 201 indicates a UE receiving an MBMS service, 211 indicates an RNC for an MBMS service, and 221 indicates an SGSN for an MBMS service.

Step 231 is a service announcement step, which transmits basic information about a specific MBMS service, for example, an identifier of the MBMS service and the availability of the service, to the UE 201. Accordingly, if there is a service to be received among the MBMS services recognized through the service announcement step, the UE 201 performs a service joining process in step 241. The joining process is performed after the UE 201 notifies the SGSN 221 of the MBMS service that it wants to receive and the SGSN 221 performs authentication on the UE 201. The UE 201 is notified of whether the MBMS service can be received. The SGSN 221 stores a list and a location of a UE 201 to receive a specific MBMS service through the service request process.

After that, when the BM-SC notifies the start of the MBMS service, in step 251, the SGSN 221 sends a session start message to the RNC9211 where the UE 201 where the UE 201 performs a service request process is located. send. In step 252, the RNC 211 transmits a service notification message to call the UE 201 to receive the MBMS service. In this case, since a plurality of UEs can be called through the service notification message transmission, step 252 is also referred to as a group calling process in a sense contrasted with the existing calling procedure. In step 261, the UEs called in step 252 transmit a response message to the SGSN 221. Through the response message transmission procedure of step 261, the RNC 211 may determine the number of UEs to receive the MBMS service for each cell and determine the type of radio channel of the corresponding cell. If the number of UEs to receive the MBMS service is greater than a predetermined predetermined threshold, the MBMS service is provided through a common channel (Point to Multi-point, hereinafter referred to as 'PtM'), and the number of UEs is defined to be a predetermined predetermined threshold. If the value is smaller than this value, a dedicated channel (Point to Point, hereinafter referred to as 'PtP') for each UE may be configured to provide the MBMS service.

In step 271, the RNC 211 transmits MBMS RB information to the UEs. The MBMS RB information includes radio channel information to be provided with MBMS service, for example, OVSF code information, transport format information, radio link control (hereinafter, referred to as RLC) information, and packet data conversion control (Packet). Data Convergence Control, hereinafter referred to as 'PDCP') information. In step 281, the UE receives an MBMS service provided through the MBMS RB received in step 271.

1 and 2 have described the system structure for the MBMS service and the process of the MBMS service. Here, the MBMS is not only an MBMS data stream, but also a control signal for controlling the MBMS service is multicast. For example, MBMS RB information to be used when providing a specific MBMS service in a specific cell is valid information for all UEs that want to receive the MBMS service in the cell. Therefore, it is efficient that control signals related to MBMS are transmitted through a common control channel configured in a cell. Currently, 3GPP, which is in charge of standardizing MBMS, is discussing a method of transmitting MBMS control signals through a new logical channel called MCCH.                         

As mentioned above. In the current 3GPP standard, SGSN transmits a session start message according to MBMS service to RNC having the following conditions.

Conditions for SGSNs to Send Session Start Messages

Condition 1. All RNCs in the routing area (hereinafter referred to as 'RA') at the last position of the idle mode.

Condition 2. Serving RNC of the connected mode UE.

Condition 3. Control RNC Requesting MBMS Service Registration

As described above, the reason why the SGSN transmits a session start message to the selective RNC in the 3GPP standard is to reduce network congestion and not waste useless resources. However, the above conditions alone fail to maintain the MBMS service context in the appropriate RNC. Accordingly, it fails to support the mobility of the UE, that is, mobility between multiple RNCs.

In this regard, FIG. 3 is a diagram illustrating a problem when SGSN transmits a session start message according to a method currently proposed in the 3GPP standard.

Referring to FIG. 3, 301 indicates an SGSN for MBMS service, and 311 indicates an RA existing under the SGSN. 321, 322, 323, and 324 all represent RNCs present in the 311 RA. At the time when a session start message for the MBMS service should be transmitted in SGSN of 301, if there is no UE in idle mode connected to the service in RA of 311 and the connected mode is connected only to RNC 2 of 322. Assume that there are UEs joining the MBMS service. The SRNC of the connected mode UE becomes 322, where the CRNC may be another RNC, but in FIG. 3, it is assumed that the CRNC is the same as the SRNC. If the CRNC has an RNC different from that of the RNC of 322, the present invention is applied as it is, and therefore, the present invention will be described with the assumption of FIG.

It can be seen from the list of UEs joining the service maintained by SGSN in the assumption that the condition 1 of the 3GPP standard is not satisfied. Accordingly, the SGSN does not transmit a session start message to all RNCs in the RA, and according to the above condition 2, only the RNC 2 of the 322 transmits a session start message. Condition 3 is not satisfied because the SRNC and the CRNC are RNC 2 of the same 322, and thus do not perform the MBMS service registration with other RNCs.

Here, if the UE in the connected mode that requested the MBMS service at 322 after moving to the cell belonging to another RNC while maintaining the connection remains after the session for the MBMS service starts, the UE through the Iur interface between the SRNC and the CRNC. The mobility information of the UE may be supported by attaching information on a service received from the SRNC to the CRNC. For example, if a UE moves from a cell belonging to RNC 2 of 322 to a cell belonging to RNC 3 of 323, even if the UE moves to the MBMS service because the RNC of 323 did not receive a session start message of 331 before moving. Although it does not have a context for the service, the context for the service may be generated through the MBMS service registration request process from the SGSN by receiving information on the MBMS service from the SRNC according to the above-described attach procedure. .

However, if the UE in the connected mode that joined the service at 322 after the session for the service starts does not maintain the connection and transitions to the idle mode and then moves to the cell to which the RNC 3 of the 323 belongs, the problem occurs. Occurs. When the idle mode UE moves to another cell, the target cell cannot know whether the idle mode UE has moved to its own cell unless the RA is changed, so the attach procedure for the connected mode UE is described. Does not occur.

Accordingly, the RNC 3 of the 323 cannot obtain information on the MBMS service from the SRNC 322 or the SGSN 301, and fails to create and maintain a context for the MBMS service. In addition, when the RNC 3 323 informs the UE of information on MBMS services that can be serviced in the current cell, the RNC 3 323 excludes the list of the MBMS service.

Accordingly, the UE recognizes the moved new cell belonging to the RNC 3 323 as a non-service area that does not support the MBMS service, thereby causing an error in UE operation that gives up the reception of the MBLMS service.

That is, according to the method of transmitting a session message currently proposed in 3GPP, the RNC cannot maintain the MBMS service context even though it is an MBMS service area, and thus cannot transmit information about the service to the UE. The MBMS service cannot be received because the request operation is not performed. Accordingly, even though the UE may request the MBMS service to receive the MBMS service, the UE may not guarantee the continuity of the MBMS service according to the mobility of the UE, thereby causing an operation error of the UE. Is not supported in the current cell, there is a problem that can not receive the MBMS service.

Accordingly, an object of the present invention, which was devised to solve the problems of the prior art operating as described above, is a method for SGSN transmitting a session start message to RNCs in an RA region for MBMS service in a mobile communication system. To provide.

It is still another object of the present invention to provide a method for maintaining and operating a list of RNCs in an RA region in which SGSN has not transmitted a session start message.

Another object of the present invention is to provide a method for supporting mobility of a terminal in a RA area and ensuring continuity of services in providing an MBMS service by providing the above method.

In a mobile communication system providing a multimedia broadcasting / multicasting service (MBMS) according to the present invention, a method of providing a broadcast service to a terminal by a service packet radio service support node (SGSN) includes a method in which the SGSN exists within a predetermined routing area. For a plurality of wireless network controllers, the process of providing a list indicating whether to transmit a message indicating the start of the broadcast service, and the SGSN detects that the predetermined terminal transitions from the connected mode to the idle mode And the SGSN checks the list to predetermined wireless network controllers to which the message is not transmitted among a plurality of wireless network controllers existing in the predetermined routing area according to a result of the checking of the list. Resending the message, and the SGSN lists the result of resending the message. It includes the process of updating the list to reflect.

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The operation principle of the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Definitions of terms to be described below should be made based on the contents throughout the specification.

Hereinafter, in the current 3GPP standard, SGSN satisfies the specification of transmitting a session start message according to MBMS service to the RNC, and proposes a method of providing an MBMS service by guaranteeing mobility of a UE.

Accordingly, the SGSN has a list of RNCs corresponding to a session start message and proposes a method of efficiently managing MBMS service contexts of the RNCs according to a session start message transmission. Therefore, the present invention proposes a method of providing the MBMS service requested by the UE by supporting mobility of the UE.

In this regard, FIG. 4 is a diagram illustrating a process of transmitting a session start message newly proposed to solve a problem caused by transmission of a session start message in 3GPP.

Referring to FIG. 4, 401, 402, 403, and 404 represent RNCs in the same RA region under the SGSN of 411, and 411 is SGSN for MBMS service. Step 421 shows the current 3GPP situation as described in FIG. 3, and indicates that all UEs that have applied for a specific MBMS service in only the cell below RNC 2 of 402 in the RA region exist in the connected mode. At this time, the SGSN 411 maintains a list of the UE through a service request process and also grasps information on the state of the UE. In step 431, the SGSN 411 determines that UEs in the connected mode that have requested the MBMS service in the RA region exist under RNC 2 of 402. At this time, it is considered that there are no UEs in idle mode that have requested the MBMS service.

Step 441 represents a session start message transmitted from the SGSN 411 to the RNCs 401, 402, 403, and 404 for the MBMS service. At this time, the session start message is transmitted only to the RNC 2 402 according to the conditions of the current standard. In step 451, after the session for the MBMS service starts, a specific UE performs a state transition to an idle mode among UEs in the connected mode in step 431. At this time, the SGSN 411 detects that the UE has transitioned to the idle mode, and step 461 through a list of other RNCs (401, 403, 404) for which a session start message has not been transmitted in the RA region. Checks whether a session start message is transmitted to all RNCs in the RA region.

That is, the SGSN 411 has a list of RNC 1, RNC3, RNC m (401, 403, 404) in the RA region that did not transmit the session start message, and thus all RNCs in the RA region. It is checked whether or not to transmit a session start message for the MBMS service. Thereafter, in step 471, the SGSN 411 determines that a session start message is not transmitted to all RNCs in the RA region, and the RNC 1, in which the session start message is not transmitted, is determined. The session start message is transmitted again to the RNC3 and RNC m (401, 403, 404). After transmitting a session start message in step 471, the SGSN 411 updates the RNC list.

In this case, the SGSN 411 allocates an identifier indicating whether the session start message is transmitted to a bit having a predetermined length in step 461 so that the session start message is not transmitted in the RA region. Manage a list of RNCs. That is, the SGSN 411 checks the list of the RNCs using the identifier. If the identifier has a value indicating that the session start message has not been transmitted, the SGSN 411 checks the list of the RNCs. . On the other hand, if the identifier has a value indicating that a session start message has been transmitted to all RNCs in the RA region, the corresponding MBMS service is provided without checking the list of the RNC.

As described above, when a specific UE of the connected mode located in the RNC that receives the session start message for the MBMS service transitions to the idle mode, the SGSN is located in the RA region. start) Resends a session start message to other RNCs for which no message has been sent, so that when the UE moves between the RNCs, all RNCs in the RA region maintain context for the MBMS service requested by the UE. It is possible. In addition, it is possible to deliver information on the MBMS service to the UE. Accordingly, the UE receives the information on the MBMS service, thereby performing the request for the MBMS service.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but is capable of various modifications within the scope of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention is a method for improving a method for transmitting a session message, which is currently proposed in 3GPP, in which SGSN transmits a session message to all RNCs located in an RA other than an RNC that provides MBMS service to the UE in consideration of UE mobility. Therefore, the RNCs located in the service area maintain the context for the MBMS service requested by the UE, thereby ensuring the continuity of the MBMS service according to the mobility of the UE, and efficiently providing the MBMS service.

Claims (4)

A method of providing a broadcast service to a terminal by a service packet radio service support node (SGSN) in a mobile communication system providing a multimedia broadcasting / multicast service (MBMS), Providing a list indicating whether or not the SGSN transmits a message indicating the start of the broadcast service to a plurality of wireless network controllers existing in a predetermined routing area; The SGSN detecting the predetermined terminal transitioning from the connected mode to the idle mode and checking the list; Transmitting, by the SGSN, the message to predetermined wireless network controllers among the plurality of wireless network controllers existing in the predetermined routing area, in which the message is not transmitted, according to a result of the checking of the list; And updating, by the SGSN, the list by reflecting a result of retransmitting the message in the list. delete The method of claim 1, The process of checking the list, Checking whether the message is transmitted to the plurality of wireless network controllers by using an identifier indicating whether the message is transmitted; If it is determined that the message is not transmitted according to the identifier, checking the list. The method of claim 3, If it is determined that the message is transmitted according to the identifier, providing the broadcast service to the terminal continuously without checking the list.

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