Abstract:
A method for enabling a user terminal to receive packet data in a mobile communication system supporting a packet data service. In the method, a radio network controller receives a session start message from a core network, determines whether or not a frequency area (FA) including the user equipment supports the MBMS service, and transmits a notification message, which contains cell reselection information used when the user equipment moves into an FA supporting the MBMS service, to the user equipment when the user equipment is located in an FA, which does not support the MBMS service.

Description:
PRIORITY  
       [0001]     This application claims priority to an application entitled “Method for Cell Reselection for Reception of Packet Data” filed in the Korean Intellectual Property Office on Aug. 7, 2003 and assigned Ser. No. 2003-54672, the contents of which are hereby incorporated by reference.  
       BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates generally to a packet data service, and more particularly to a method by which a user equipment located in a geographical area including a plurality of overlapping cells having different frequency bands can receive packet data of a packet data service provided to at least one cell selected from the plurality of cells in the geographical area.  
         [0004]     2. Description of the Related Art  
         [0005]      FIG. 1  is a block diagram schematically illustrating a conventional mobile communication system. In  FIG. 1 , the mobile communication system is a universal mobile terrestrial system (UMTS) mobile communication system that includes a core network (CN)  100 , multiple radio network subsystems (RNSs)  110  and  120 , and a user element (UE)  130 . Each of the RNSs  110  and  120  includes a radio network controller (RNC) and multiple base stations (or node Bs). For example, the RNS  110  includes a RNC  111 , and node Bs  113  and  115 , and the RNS  120  includes a RNC  112 , and node Bs  114  and  116 .  
         [0006]     Further, each of the RNCs  111  and  112  may be classified as a serving RNC (SRNC), a drift RNC (DRNC), or a controlling RNC (CRNC) according to an operation of each RNC. The SRNC is an RNC for managing information of each UE and controlling data transmission with the CN  100 . Further, when data of a UE is transmitted/received to/from a SRNC via another RNC other than the SRNC, the DRNC becomes the another RNC.  
         [0007]     The CRNC is an RNC for controlling each node B. When the RNC  111  manages the information of the UE  130  as illustrated in  FIG. 1 , the RNC  111  operates as a SRNC with respect to the UE  130 . Further, when the UE  130  moves and the data of the UE  130  is transceived through the RNC  112 , the RNC  112  becomes a DRNC with respect to the UE  130 , and the RNC  111  controlling the node B  113  communicating with the UE  130  becomes a CRNC of the node B  113 .  
         [0008]     The RNC and the node B are connected to each other through a lub interface. The RNCs are connected to each other through a lur interface. The UE and a UTRAN are connected to each other through a Uu interface.  
         [0009]     The RNC assigns a radio resource to multiple node Bs controlled by the RNC and the node B provides the UE with the radio resource assigned by the RNC. The radio resource is provided according to each cell, and the radio resource provided by the node B represents a radio resource regarding a specific cell controlled by the node B.  
         [0010]     The UE sets a radio channel by means of the radio resource regarding the specific cell controlled by the node B, and transmits/receives data by means of the set radio channel. Accordingly, because the UE recognizes only a physical channel provided according to each cell, a distinction between a node B and a cell has no meaning. Hereinafter, the present invention uses the terms a node B and a cell interchangeably.  
         [0011]     In order to support multicasting multimedia communication, a broadcastlmulticast service provides a service from one data source to a plurality of user equipments (UEs). The broadcast/multicast service may be classified as a cell broadcast service (CBS), a message-centered service, and a multimedia broadcast/multicast service (MBMS) supporting a multimedia such as a real-time image and voice, a still image, characters, etc.  
         [0012]      FIG. 2  is a block diagram schematically illustrating a network for providing the MBMS service in the mobile communication system. Referring to  FIG. 2 , a broadcast/multicast-service center (BM-SC)  210  provides an MBMS stream, and schedules a stream for the MBMS service to transmit the stream to a transit network  220 . The transit network  220  is a network located between the BM-SC  210  and a serving GPRS support node (SGSN)  230  and sends the stream for the MBMS service, which is received from the BM-SC  210 , to the SGSN  230 . Herein, it is assumed that the SGSN  230  may include a gateway GPRS support node (GGSN) and an external network, etc., and that there are multiple UEs intending to receive the MBMS service at a predetermined time point, e.g., a UE  261 , a UE  262 , and a UE  263 , each belonging to a first cell (node B 1 )  260 , and a UE  271  and a UE  272 , each belonging to a second cell (node B 2 )  270 .  
         [0013]     The SGSN  230  having received the stream for the MBMS service from the transit network  220  controls an MBMS related service of UEs intended for reception of a MBMS service. For example, the SGSN  230  manages MBMS service accounting related data of each UE and selectively transmits MBMS service data to a specific RNC  240 . Further, the SGSN  230  creates and manages an SGSN service context for the MBMS service X, and transmits the stream for the MBMS service to the RNC  240  again.  
         [0014]     The RNC  240  controls a plurality of node Bs and transmits the MBMS service data to a node B, which includes a UE requesting the MBMS service, from among the node Bs controlled by the RNC  240 , controls a radio channel set for providing the MBMS service, and creates and manages a RNC service context for the MBMS service X with the stream for the MBMS service received from the SGSN  230 . Further, as illustrated in  FIG. 2 , only one radio channel is assigned to one node B, e.g., a Node B  260  and UEs  261  to  263 , in order to provide the MBMS service. Further, a home location register (HLR) is connected to the SGSN  230  to perform an subscriber authentication for the MBMS service.  
         [0015]      FIG. 3  is a view illustrating a process through which the MBMS service is provided between a RNC and a UE requesting the MBMS service. The RNC provides the MBMS service to corresponding UEs requesting the MBMS service via a node B. Herein, it is clear that the MBMS service is performed via a node B. Further, a MBMS control message transmitted for the MBMS service will also be described.  
         [0016]     Referring to  FIG. 3 , a UE  300  is a UE intended for reception of the corresponding MBMS service and an RNC  302  is RNC transmitting the MBMS service. Four steps are sequentially performed in a sequence of an announcement step, a joining step, a notification step, and a radio bearer (RB) setup step. Hereinafter, the four steps will be described with reference to  FIG. 3 .  
         [0017]     In step  331 , i.e., the announcement step, an SGSN  304  informs the UE  300  of a start time of the MBMS service. Herein, the information contains the kinds of MBMS services, time information on a start of the MBMS services, and duration of the MBMS services.  
         [0018]     In step  341 , the UE  300  requesting the MBMS services performs the joining step for the SGSN  304  according to the MBMS service notification by the SGSN  304 . In the joining step, the UE  300  transmits a joining request message requesting a joining to the SGSN  304 . The joining request message includes the identification code of a specific MBMS service, which is requested by the UE  300 , and the identifier (UE ID) of the UE  300  requesting the MBMS service from among a MBMS service list transmitted from the SGSN  304 .  
         [0019]     Further, in step  341 , the SGSN  304  performs an authentication process for the UE  300  requesting the MBMS service, and notifies the UE  300  of information regarding whether or not the UE  300  can receive the MBMS service from the result of the authentication. The SGSN  304  stores a list of UEs intended for reception of the specific MBMS service and the positions of the UEs by performing step  341 .  
         [0020]     In the mobile communication system, when the joining step for the MBMS service has been completed, the notification step, which is illustrated in steps  351 ,  352 , and  361 , is performed. More specifically, when a BM-SC reports the start of the MBMS service, the SGSN  304  transmits a session start message to the RNC  302  including the UE  300  having performed the joining process, in step  351 . In step  352 , the RNC  302  transmits a notification message for paging the UE  300 , which is to receive the MBMS service, by means of a common channel, such as a secondary-common control channel (S-CCPCH). The notification is a process through which the SGSN informs the corresponding UE  300  requesting the MBMS service of the start of the MBMS service. Because a plurality of UEs are paged through the transmission of the notification message, step  352  is called a group paging step for the distinction with the existing paging procedure. For example, the notification message can be transmitted through a MBMS control channel (MCCH).  
         [0021]     In step  361 , the UE  300  paged in step  352  transmits a response message for the notification message. Through the transmission of the response message, the RNC  302  can check the number of UEs intended for reception of the MBMS service according to cells, and determine the kind of radio channels of a corresponding cell. The RNC  302  does not count all UEs intended for reception of the MBMS service. Instead, the RNC  302  counts the UEs only until the number of the UEs can satisfy a threshold for channel type decision. When a plurality of UEs contained in a specific cell intend to receive a MBMS service, the RNC  302  provides the MBMS service through a common channel. However, when a cell contains a small number of UEs intended for reception of the MBMS service, the RNC  302  can assign a dedicated channel according to each UE and provide the MBMS service.  
         [0022]     In step  371 , the UE  300  requesting the MBMS service and performing the step relating to the notification performs the radio bearer setup step by means of radio bearer information transmitted by the RNC  302  through an MCCH. The radio bearer setup step is a step in which a radio resource is actually assigned in order to provide the MBMS service and in which information on the radio resource is announced to relating devices. Further, in the radio bearer setup step, MBMS radio bearer information enabling the MBMS service to be received without an error is transmitted. That is, the UE  300  can restore the transmitted MBMS service without an error by using the MBMS radio bearer information. The MBMS radio bearer information may include radio channel information such as OVSF code information, transmission format information, radio link control (RLC) information, packet data convergence protocol (PDCP) information, etc. A detailed description about the information is disclosed in a 3GPP TS 26.331.  
         [0023]     When the radio bearer setup step has been completed, all UEs intended for reception of a specific MBMS service recognize information on a radio link through which the MBMS service is provided and information on an upper layer in which the MBMS service is processed.  
         [0024]     In step  381 , when the RNC  302  transmits MBMS data transmitted from the SGSN  304  through a set MBMS RB, the UE  300  receives the MBMS data provided through the MBMS RB.  
         [0025]     As indicated above, the MCCH is a channel through which control information on the MBMS is provided. Specific characteristics of this channel are currently being discussed and have not been standardized yet. According to recent discussions, an MCCH is expected to have the following characteristics:  
         [0026]     1. one MCCH is constructed per cell;  
         [0027]     2. an MCCH is transmitted thorough a common physical channel such as an S-CCPCH; and  
         [0028]     3. UEs can obtain information on an MCCH assigned according to each cell as system information.  
         [0029]      FIG. 4  illustrates a structure in which a plurality of frequency areas (FAs) overlap in one area. As illustrated in  FIG. 4 , one RNC includes at least one FA and a plurality of FAs can perform a MBMS service in the same area. That is, in servicing the same MBMS data in the same area, radio resources that are different from each other are used.  
         [0030]     More specifically,  FIG. 4  illustrates four FAs, that is, FAs  401  to  404 . The four FAs service one MBMS data with respect to the same area. A UE contained in one of the four FAs can receive MBMS data transmitted from the FA including the UE. That is, the area is a single area in view of geographical concept, but the area includes four cells having different frequencies in view of FA supporting the MBMS data.  
         [0031]     It is assumed that a plurality of FAs overlap in the aforementioned one area and each of the FAs services the same MBMS data to at least one UE. Herein, a plurality of radio resources are used for the same MBMS data, thereby wasting the radio resources.  
         [0032]     Accordingly, when multiple FAs overlap in one area, at least one FA of the FAs is selected and MBMS data can be provided. Further, when the MBMS service is impossible in a specific FA having multiple overlapping FAs using one area, there is a problem in that the UE contained in the FA in which the MBMS service is impossible cannot receive the MBMS service.  
         [0033]     Referring to  FIG. 4 , when only the FA  402  can support the MBMS service and the FAs  401 ,  403 , and  404  do not support the MBMS service, the UEs contained in the FAs  401 ,  403 , and  404  cannot receive the MBMS service. Accordingly, a method is necessary, which enables even a UE contained an FA that does not support the MBMS service to receive the MBMS service.  
       SUMMARY OF THE INVENTION  
       [0034]     Accordingly, the present invention has been designed to solve the above and other problems occurring in the prior art, and it is an object of the present invention to provide a method of efficiently using a radio resource managed by each of multiple FAs, when multiple cells overlap in the same area.  
         [0035]     It is another object of the present invention to provide a method enabling a UE contained in a cell that does not support a packet data service to receive the packet data service, when the cell that does not support the packet data service for the same area and a cell supporting the packet data service for the same area overlap in the same area.  
         [0036]     It is further another object of the present invention to provide a method by which a UE determines if a cell including the UE is a cell supporting a packet data service.  
         [0037]     In order to accomplish the above and other objects, according to one aspect of the present, there is provided a method for receiving a packet data service in a mobile communication system. The method includes the steps of: notifying cell reselection information of a user equipment located in a cell which does not support the packet data service, the cell reselection information being used when the user equipment moves into a cell supporting the packet data service; assigning a radio resource for supporting the packet data service; and receiving packet data through the assigned radio resource according to the notified cell reselection information.  
         [0038]     According to another aspect of the present, there is provided a method for enabling a user equipment located in an FA that does not support a multimedia broadcast/multicast service (MBMS) to receive the MBMS service in a mobile communication system. The method includes the steps of: receiving a notification message from a radio network controller; confirming a service ID of the notification message; determining if the notification message is a notification message for the MBMS service requested by the user equipment; confirming information for reselecting an FA supporting the MBMS service from the notification message when the notification message is the notification message for the MBMS service requested by the user equipment as a result of the determination; and receiving the MBMS service through a radio resource assigned to the FA on the basis of the confirmed information.  
         [0039]     According to another aspect of the present, there is provided a method for transmitting an MBMS service to a user equipment in a mobile communication system. The method includes the steps of: receiving a session start message from a core network and then determining whether or not an FA including the user equipment supports the MBMS service; transmitting a notification message, which contains cell reselection information used when the user equipment moves into an FA supporting the MBMS service, to the user equipment when the user equipment is located in an FA which does not support the MBMS service; and receiving the MBMS service through a radio resource of the FA supporting the MBMS service by means of the notification message. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0040]     The above and other objects, features, and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:  
         [0041]      FIG. 1  is a block diagram schematically illustrating a conventional mobile communication system;  
         [0042]      FIG. 2  is a block diagram illustrating a structure of an MBMS system;  
         [0043]      FIG. 3  is a view illustrating an operation between each node in a mobile communication system supporting an MBMS service;  
         [0044]      FIG. 4  is a view illustrating a structure in which a plurality of cells overlap in one area;  
         [0045]      FIG. 5  is a view illustrating an operation between each node in a mobile communication system supporting an MBMS service according to the present invention;  
         [0046]      FIG. 6  is a flowchart illustrating an operation of an RNC supporting a MBMS service according to the present invention; and  
         [0047]      FIG. 7  is a flowchart illustrating an operation of a UE receiving an MBMS service according to the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0048]     Preferred embodiments of the present invention will be described in detail herein below with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configuration incorporated herein will be omitted when it may obscure the subject matter of the present invention.  
         [0049]      FIG. 5  is a view illustrating a process, through which a MBMS service is supported to a UE included in an FA that does not support the MBMS service, according to an embodiment of the present invention. More specifically,  FIG. 5  illustrates an SGSN  521  and an RNC  511  supporting a MBMS service, and a plurality of UEs  501  to  503 , which are located in an FA that can support the MBMS service provided from the RNC  511  and an FA that cannot support the MBMS service provided from the RNC  511 . Herein, the FA that can support the MBMS service and the FA that cannot support the MBMS service include at least one UE.  
         [0050]     Referring to  FIG. 5 , the FA capable of supporting the MBMS service and the UEs included in the FA are expressed by a reference numeral  501 . The FA that cannot support the MBMS service and the UEs included in the FA are expressed by reference numerals  502  and  503 .  
         [0051]     In the present invention, in order to transmit the MBMS service to corresponding UEs, a service announcement step, a joining step, a notification step, and a radio bearer (RB) setup step are sequentially performed as illustrated in  FIG. 3 . However,  FIG. 5  does not show the service announcement step and the joining step, but it is clear to those who skilled in the art that the service announcement step and the joining step must be performed before the notification step.  
         [0052]     After performing the service announcement step and the joining step, the SGSN  521  transmits a session start message to the RNC  511  in step  531 . The session start message contains information on a MBMS service ID, a quality of service (QoS) parameter, etc., of a corresponding MBMS service to be immediately provided. The RNC  511  having received the session start message classifies FAs as FAs that can support the MBMS service and FAs that cannot support the MBMS service, and transmits different notification messages to the classified FAs. For example, in step  541 , the RNC  511  transmits a notification message to the UEs  501  contained in the FA capable of supporting the MBMS service. The notification message contains the MBMS service ID, a none service area (NSA)/service area (SA) indicator, which indicates whether or not a corresponding FA including the UEs  501  to  503  supports the MBMS service, a resource availability indicator, etc. That is, in step  541 , the RNC  511  sets the NSA/SA indicator to be an SA and transmits the notification message.  
         [0053]     Herein, the NSA/SA indicator is defined according to each MBMS service. Further, setting a predetermined FA to be an SA indicates that the MBMS service is currently provided or that the FA is an area capable of supporting the MBMS service at some future time. However, setting a predetermined FA to be an NSA indicates that the FA is an area not capable of supporting the MBMS service currently or at some future time.  
         [0054]     Further, when a cell currently belongs to an SA for a MBMS service, the resource availability indicator signifies whether or not a resource enabling the MBMS service to be provided exists.  
         [0055]     In steps  542  and  543 , the RNC  511  transmits a notification message to the UEs  502  and  503  contained in the FA that cannot support the MBMS service. The notification message of steps  542  and  543  further contains cell reselection information for MBMS for receiving the MBMS service, in addition to information contained in the notification message of step  541 . That is, the information contained in the notification message of steps  542  and  543  is different from that contained in the notification message of steps  541 .  
         [0056]     The cell reselection information for MBMS is additional information that enables the UEs  502  and  503  contained in the FA that cannot support the MBMS service to receive the MBMS service. Further, the cell reselection information for MBMS contains frequency information, a cell ID, cell information, etc., of a target cell  501  supporting the MBMS service. The frequency information, the cell ID, and the cell information are variable information and are not contained in the notification message of step  541  as described above.  
         [0057]     The frequency information contains an uplink UTRA absolute radio frequency channel number (UARFCN) and a downlink UARFCN.  
         [0058]     The cell ID represents an identifier of a cell corresponding to a frequency area supporting the MBMS service.  
         [0059]     The cell information represents, for example, a primary scrambling code of a primary common pilot channel (P-CPICH) with respect to an FA supporting the MBMS service.  
         [0060]     Additionally, Priorities in transmitting the notification messages in steps  541 ,  542 , and  543  may be changed. That is, step  541  may be performed after steps  542  and  543  are performed.  
         [0061]     In step  551 , the UEs  502  and  503  contained in the FAs, which cannot or does not support the MBMS service, move into a corresponding cell of the FA capable of supporting the MBMS service by means of the cell reselection information for MBMS transmitted through steps  542  and  543 . That is, the UEs  502  and  503  confirm the cell reselection information for MBMS contained in the notification message and reselect the FA  501  supporting the MBMS service. The UEs  502  and  503  perform a process for the cell reselection, thereby receiving the MBMS service, which is transmitted from the RNC  511 , by means of a radio resource equal to that used in the UEs  501 .  
         [0062]     In steps  542  and  543 , when the service ID contained in the notification message does not coincide with a service ID of a service in which the UEs  502  and  503  have joined, it is unnecessary to perform step  551 .  
         [0063]     In step  561 , the RNC  511  can calculate the number of UEs, which are intended for reception of the MBMS service, for channel type decision in a cell of the FA  501  supporting the MBMS service, and can determine the kind of radio channels of a corresponding cell. That is, the RNC  511  calculates the number of UEs in the cell, which includes the UEs  502  and  503  having reselected the FA  501  supporting the MBMS service, and determines the kind of radio channels of the cell. When a plurality of UEs in the cell are intended for reception of a MBMS service, the RNC  511  provides the MBMS service through a common channel. However, when the number of UEs intended for reception of the MBMS service is small, the RNC  302  assigns a dedicated channel according to each UE and provides the MBMS service. Counting  561  can be also started after step  531 .  
         [0064]     In step  571 , the RNC  511  transmits the determined radio bearer information through a MCCH to perform the radio bearer setup step. The radio bearer setup step is a step in which the radio channel determined for providing the MBMS service is actually assigned and in which information on the radio channel is announced to relating devices.  
         [0065]     In step  581 , the UEs in the cell of the FA  501  supporting the MBMS service receive the MBMS service, which is transmitted by the RNC  511 , through the MBMS radio channel set in step  571 .  
         [0066]     As described above, after receiving the session start message, which reports the start of the MBMS service requested by the UEs  501  to  503 , from the SGSN  521 , the RNC  511  transmits a notification message containing the MBMS service ID and the cell reselection information for MBMS to the UEs  502  and  503  contained in the FAs that cannot or do not support the MBMS service. Accordingly, the UEs  502  and  503  having received the notification message reselect an FA, to which the MBMS service is provided, by means of the information contained in the notification message, and receive the MBMS service.  
         [0067]      FIG. 6  is a flowchart illustrating an operation of a RNC transmitting a notification message according to an embodiment of the present invention. In step  601 , the RNC receives a session message, which is used to report an immediate start of a specific MBMS service requested by predetermined UEs located in a plurality of FAs existing under the control of the RNC, from a SGSN. Herein, the RNC controls an FA supporting the MBMS service and an FA that cannot support the MBMS service. Accordingly, the RNC differently sets notification messages to be transmitted to the FAs in relation to the MBMS service.  
         [0068]     In step  602 , the RNC sets common information that must be transmitted to UEs contained in the FA supporting the MBMS service and UEs contained in the FA that cannot support the MBMS service, in relation to the MBMS service. The common information includes an MBMS service ID, an NSA/SA indicator, a resource availability indicator, etc.  
         [0069]     When the notification message is transmitted to the FA supporting the MBMS service, the NSA/SA indicator is set to be an SA. However, when the notification message is transmitted to the FA that does not support the MBMS service, the NSA/SA indicator is set to be an NSA.  
         [0070]     In step  611 , the RNC confirms whether the notification message is a messages for the FA supporting the MBMS service or the FA that does not support the MBMS service. Herein, the RNC confirms the NSA/SA indicator of the notification messages.  
         [0071]     When the notification message is a notification messages for the FA that does not support the MBMS service, that is, the NSA/SA indicator has been set to be an NSA, step  612  is performed. However, when the notification message is a notification messages for the FA supporting the MBMS service, that is, the NSA/SA indicator has been set to be an SA, step  613  is performed.  
         [0072]     In step  612 , the RNC adds cell reselection information for MBMS for receiving the MBMS service to the notification messages containing the MBMS service ID set in step  602 . That is, the RNC includes frequency information, a cell ID, and cell information of the FA supporting the MBMS service into the notification messages for the FA that does not support the MBMS service.  
         [0073]     In step  613 , the RNC transmits the notification message set in step  602  or step  612  to a corresponding FA.  
         [0074]     In  FIG. 6 , the RNC firstly sets information that must be commonly transmitted to the FA supporting the MBMS service and the FA that does not support the MBMS service, and then adds the cell reselection information for MBMS with respect to the FA that does not support the MBMS service. That is, the RNC firstly determines whether an FA to which the notification message must be transmitted is the FA supporting the MBMS service or the FA that does not support the MBMS service. Herein, the determination is accomplished according to whether the NSA/SA indicator to be set in the notification message is set or not. When it is assumed that the notification message is set to be an FA supporting the MBMS service, that is, an SA, the RNC sets a notification message containing the information of step  602 . However, when it is assumed that the notification message is set to be an FA that does not support the MBMS service, that is, an NSA, the RNC sets a notification message containing all information of steps  602  and  612 . Herein, steps  602  and  612  can be performed by one step.  
         [0075]     As described above, in the present invention, the RNC can set different information to be contained in the notification message according to characteristics of an FA transmitting the notification message, and transmit the information.  
         [0076]      FIG. 7  is a flowchart illustrating an operation of a UE according to an embodiment of the present invention. More specifically,  FIG. 7  illustrates a process, through which UEs contained in an FA that does not support a MBMS service perform a cell reselection for receiving the MBMS service after receiving transmits the notification message transmitted by the RNC in  FIG. 6 , according to the present invention.  
         [0077]     Referring to  FIG. 7 , in step  701 , a UE receives a notification message, which relates to a MBMS service in which the UE has joined, from a RNC. The UE determines whether or not the MBMS service is a MBMS service requested by the UE by means of a MBMS service ID contained in the notification message. Hereinafter, because only a case in which the MBMS service ID contained in the notification message coincides with an ID of a MBMS service requested by the UE will be described in relation to the present invention, a more detailed description will be omitted.  
         [0078]     In step  702 , the UE analyzes information set in the notification message. More specially, the UE confirms an NSA/SA indicator of the set information and determines whether an FA including the UE is an FA supporting the MBMS service or an FA that does not support the MBMS service. When the NSA/SA indicator is set to be an SA, that is, the FA including the UE is the FA supporting the MBMS service, step  713  is performed. However, when the NSA/SA indicator is set to be an NSA, that is, the FA including the UE is the FA that does not support the MBMS service, step  711  is performed.  
         [0079]     In step  711 , the UE determines if cell reselection information for MBMS is contained in the received notification message. The cell reselection information for MBMS contains information used when the UE contained in the FA that does not support the MBMS service moves into the FA supporting the MBMS service for receiving the MBMS service. That is, the UE confirms whether or not the notification message contains frequency information, a cell ID, and cell information of the FA supporting the MBMS service.  
         [0080]     When the received notification message contains the cell reselection information for MBMS, step  712  is performed. However, when the received notification message does not contain the cell reselection information for MBMS, step  714  is performed. That is, the UE request MBMS service related information again. The MBMS service related information may include information on a request of cell reselection information for MBMS or an operation reporting that the cell reselection information for MBMS does not exist in the transmitted notification message.  
         [0081]     In step  712 , the UE obtains information on the FA supporting the MBMS service by means of the cell reselection information for MBMS contained in the notification message. Further, the UE moves into the FA supporting the MBMS service by means of the obtained information. That is, the UE reselects a cell by means of the frequency information, the cell ID, and the cell information of the FA supporting the MBMS service, thereby receiving the MBMS service.  
         [0082]     Through the performance of the steps, the UE contained in the FA that does not support the MBMS service can receive the MBMS service transmitted from the RNC. That is, in step  713 , the UE transmits a response message for the notification message to the RNC. The UE receives the MBMS service, which is transmitted from the RNC, by means of a radio resource used in the FA supporting the MBMS service.  
         [0083]     As described above, in the present invention, when a cell that does not support a packet data service and a cell supporting the packet data service overlap in the same area, radio resource information on the cell supporting the packet data service is notified to a UE contained in the cell that does not support the packet data service. Accordingly, a support is performed for a UE located in a specific area by means of one radio resource, thereby efficiently managing the radio resource for the packet data service.  
         [0084]     While the present invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.