Abstract:
A method is provided for updating neighbor base station (BS) information by a serving BS in a communication system. The method includes acquiring a neighbor BS list from a base station controller (BSC); sending a request message for requesting an update of information on a neighbor BS to the at least one neighbor BS included in the neighbor BS list; checking if a report message including the neighbor BS&#39;s information is received from the neighbor BS; when the report message is received, sending to the neighbor BS a confirm message indicating the normal receipt of the report message; and updating the neighbor BS&#39;s information according to the received neighbor BS&#39;s information. The neighbor BS list is a list of BSs with which a mobile station (MS) located in a cell of the serving BS can perform a handover.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) AND CLAIM OF PRIORITY 
       [0001]    The present application claims the benefit under 35 U.S.C. §119(a) of a Korean Patent Application filed in the Korean Intellectual Property Office on Oct. 5, 2007 and assigned Serial No. 2007-100487, the disclosures of which are incorporated herein by reference. 
       TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates to a system and method for updating neighbor base station (BS) information in a communication system. 
       BACKGROUND OF THE INVENTION 
       [0003]    The next-generation communication system has been developing to guarantee high-speed data transmission/reception while ensuring the mobility of mobile stations (MSs). The typical next-generation communication system can include an Institute of Electrical and Electronics Engineers (IEEE) 802.16e communication system. In the IEEE 802.16e communication system, a handover acts as a very important factor in guaranteeing the mobility of MSs. The term ‘handover’ as used herein indicates an operation of allowing an MS in service to receive a seamless service even while moving from one base station (BS) to another BS. That is, the ‘handover’ represents an operation of allowing an MS to move to a target BS from which it can receive a higher-quality service as the quality of the service decreases, which it is receiving from a serving BS to which it now belongs, thereby receiving the seamless service. 
         [0004]    In the IEEE 802.16e communication system, in order to support the handover of an MS, the serving BS sends neighbor BS information to the MS using a neighbor BS advertisement or MOBile_NeighBoR_ADVertisement (MOB_NBR-ADV) message. 
         [0005]      FIG. 1  is a signaling diagram illustrating a process of updating neighbor BS information by a serving BS in a general communication system. 
         [0006]    Referring to  FIG. 1 , in step  101 , a serving BS  100  generates its neighbor BS list at the time the communication system first sets up the serving BS  100 , and then proceeds to step  103 . Although the list of neighbor BSs can be acquired at the time the serving BS  100  is first set up, the serving BS  100  can also acquire the neighbor BS list from a base station controller (BSC). When generating a MOB_NBR-ADV message, the serving BS  100  includes the neighbor BS list therein. The serving BS  100  stores the neighbor BS list in its radio resource controller (RRC). In step  103 , the serving BS  100  sends a Radio_Configuration_Update_Request (Radio_Config_Update_Req) message to a target BS  150 , one of the neighbor BSs, to acquire downlink channel descriptor (DCD) information and uplink channel descriptor (UCD) information of the neighbor BSs included in the neighbor BS list. For convenience, it is assumed in  FIG. 1  that the neighbor BS list includes one neighbor BS (i.e., target BS  150 ). However, the neighbor BS list can include a plurality of neighbor BSs. In this case, the serving BS  100  sends the Radio_Config_Update_Req message to all neighbor BSs included in the neighbor BS list. 
         [0007]    In step  105 , the target BS  150  sends to the serving BS  100  a Radio_Configuration_Update_Report (Radio_Config_Update_Rpt) message with DCD information and UCD information of the target BS  150 . 
         [0008]    In step  107 , the serving BS  100  updates the neighbor BS list so that it includes DCD information and UCD information of the target BS  150 . 
         [0009]    Although not illustrated in  FIG. 1 , the target BS  150  may occasionally fail to receive the Radio_Config_Update_Req message sent by the serving BS  100  due to an operational problem. In this case, the target BS  150 , since it has failed to receive the Radio_Config_Update_Req message, cannot send a Radio_Config_Update_Rpt message with DCD information and UCD information of the target BS  150  to the serving BS  100 , causing a problem that the serving BS  100  cannot acquire DCD information and UCD information of the target BS  150 . 
         [0010]    Also, even though the target BS  150  has sent the Radio_Config_Update_Rpt message to the serving BS  100 , the serving BS  100  may occasionally fail to receive the Radio_Config_Update_Rpt message due to a loss of the Radio_Config_Update_Rpt message. Even in this case, the serving BS  100  cannot acquire DCD information and UCD information of the target BS  150 . 
         [0011]    In the above-stated message exchange procedure between the serving BS  100  and the target BS  150  for updating DCD information and UCD information of the neighbor BS, since the target BS  150  may occasionally fail to receive the Radio_Config_Update_Req message or the serving BS  100  may occasionally fail to receive the Radio_Config_Update_Rpt message, the neighbor BS information managed by the serving BS  100  may not be identical to the neighbor BS information managed by the target BS  150 , making it impossible for the MS to perform handover. 
       SUMMARY OF THE INVENTION 
       [0012]    To address the above-discussed deficiencies of the prior art, it is a primary aspect of the present invention to address at least the problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a system and method for updating neighbor BS information in a communication system. 
         [0013]    Another aspect of the present invention is to provide a system and method for adding a procedure for sending to a neighbor BS a confirm message indicating the update of neighbor BS information when it is updated in a serving BS information update procedure in a communication system. 
         [0014]    Another aspect of the present invention is to provide a system and method in which a serving BS and a neighbor BS each acquire a corresponding neighbor BS list from their upper layer and store the neighbor BS list, thereby updating neighbor BS information regardless of a serving BS&#39;s request. 
         [0015]    According to one aspect of the present invention, there is provided a method for updating neighbor base station (BS) information by a serving BS in a communication system. The method includes acquiring a neighbor BS list from a base station controller (BSC); sending a request message for requesting update of information on a neighbor BS to the at least one neighbor BS included in the neighbor BS list; checking if a report message including the neighbor BS&#39;s information is received from the neighbor BS; when the report message is received, sending to the neighbor BS a confirm message indicating the normal receipt of the report message; and updating the neighbor BS&#39;s information according to the received neighbor BS&#39;s information. The neighbor BS list is a list of BSs to which a mobile station (MS) located in a cell of the serving BS can perform handover. 
         [0016]    According to another aspect of the present invention, there is provided a method for updating neighbor base station (BS) information by a neighbor BS in a communication system. The method includes acquiring a neighbor BS list from a base station controller (BSC); upon perceiving a change in a neighbor BS information of the neighbor BS itself, sending a report message including the changed neighbor BS information to at least one serving BS included in the neighbor BS list; and checking if a confirm message indicating normal receipt of the report message is received from the serving BS. The neighbor BS list is a list of BSs of cells where mobile stations (MSs) are located, which intend to perform handover to a cell of the neighbor BS. 
         [0017]    According to further another aspect of the present invention, there is provided a system for updating neighbor base station (BS) information in a communication system. The system includes a serving BS which includes sending a request message for requesting update of information on a neighbor BS to the at least one neighbor BS included in a neighbor BS list acquired from a base station controller (BSC); checking if a report message including the neighbor BS&#39;s information is received from the neighbor BS; when the report message is received, sending to the neighbor BS a confirm message indicating the normal receipt of the report message; and updating the neighbor BS&#39;s information according to the received neighbor BS&#39;s information. The neighbor BS list is a list of BSs to which a mobile station (MS) located in a cell of the serving BS can perform handover. 
         [0018]    According to yet another aspect of the present invention, there is provided a system for updating neighbor base station (BS) information in a communication system. The system includes a neighbor BS which includes acquiring a neighbor BS list from a base station controller (BSC); upon perceiving a change in a neighbor BS information of the neighbor BS itself, sending a report message including the changed neighbor BS information to at least one serving BS included in the neighbor BS list; and checking if a confirm message indicating normal receipt of the report message is received from the serving BS. The neighbor BS list is a list of BSs of cells where mobile stations (MSs) are located, which intend to perform handover to a cell of the neighbor BS. 
         [0019]    Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation, such a device may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with any particular controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]    For a more complete understanding of the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts: 
           [0021]      FIG. 1  is a signaling diagram illustrating a process of updating neighbor BS information by a serving BS in a general communication system; 
           [0022]      FIG. 2A  is a signaling diagram illustrating an exemplary operation of updating neighbor BS information by a serving BS in a communication system according to an embodiment of the present invention; 
           [0023]      FIG. 2B  is a signaling diagram illustrating another exemplary process of updating neighbor BS information by a serving BS in a communication system according to an embodiment of the present invention; 
           [0024]      FIG. 3  is a flowchart illustrating an operation of a serving BS in a communication system according to an embodiment of the present invention; and 
           [0025]      FIG. 4  is a flowchart illustrating an operation of a target BS in a communication system according to an embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0026]      FIGS. 2A through 4 , discussed below, and the various embodiments used to describe the principles of the present disclosure in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the disclosure. Those skilled in the art will understand that the principles of the present disclosure may be implemented in any suitably arranged wireless communication system. 
         [0027]    The present invention provides a system and method for updating neighbor base station (BS) information in a communication system. Specifically, the present invention provides a system and method in which a serving BS updates a list of neighbor base stations. 
         [0028]    For example, an embodiment of the present invention provides a system and method for, when an MS intends to perform handover from its serving BS to a target BS, updating information on each neighbor BS through a message exchange between the serving BS and the target BS to match information on neighbor BSs shared by the serving BS and the target BS. However, the proposed neighbor BS information updating system and method can be applied to a communication system that updates the neighbor BS information and transmits/receives it on a MOB_NBR-ADV message rather than performing the handover of an MS. 
         [0029]    Before a description of the present invention is given, a definition will be given of a neighbor BS list stored in each of the serving BS and the target BS. 
         [0030]    A serving BS of a cell where an MS is currently located has as its neighbor BS list a target BS list, which is a list of target BSs situated in a cell that the MS intends to enter through handover. The serving BS list is composed of at least one neighbor BS identifier and information (i.e., DCD/UCD information) of its associated neighbor BS. Therefore, the serving BS sends a request for DCD/UCD information to a corresponding target BS and configures a MOB_NBR-ADV message with the target BS information. However, since the target BS has no information on a serving BS list, the serving BS should periodically send a DCD/UCD information request to the target BS, causing generation of traffic unnecessary for the network. When a transmission period of the DCD/UCD information request is increased to reduce the traffic generation, the update time may be delayed, so that handover may not be normally performed. 
         [0031]    Therefore, according to the present invention, the target BS has as its neighbor BS list a serving BS list, which is a list of BSs situated in cells where an MS is located, which intend to enter the cell where the MS is located. The target BS list is composed of at least one neighbor BS identifier and information (i.e., DCD/UCD information) of its associated neighbor BS. 
         [0032]    To be specific, assume that the communication system is composed of 3 cells of a cell A, a cell B and a cell C. BSs and MSs located in the cell A, the cell B and the cell C are defined as BS_A, BS_B and BS_C, and MS_A, MS_B and MS_C. 
         [0033]    As for the cell A where the MS_A is located, the MS_A intends to move from the cell A to the cell B and the MS_B intends to enter the cell A. In this case, a target BS list of the BS A has the BS_B, and a serving BS list of the BS_A has BS_B. 
         [0034]    Regarding the cell B where the MS_B is located, the MS_B intends to move from the cell B to the cell A and the MS_A and the MS_C intend to enter the cell B. In this case, a target BS list of the BS_B has the BS_A, and a serving BS list of the BS_B has the BS_A and the BS_C. 
         [0035]    Regarding the cell C where the MS_C is located, the MS_C intends to move from the cell C to the cell B and there is no MS intending to enter the cell C. In this case, a target BS list of the BS_C has the BS_B, and a serving BS list of the BS_C has no BS. 
         [0036]    The above-defined target BS list and serving BS list of the serving BS and the target BS are acquired from a corresponding BSC(s). 
         [0037]      FIG. 2A  is a signaling diagram illustrating an exemplary operation of updating neighbor BS information by a serving BS in a communication system according to an embodiment of the present invention. 
         [0038]    Referring to  FIG. 2A , in step  201   a,  a serving BS  200  generates a target BS list, and then proceeds to step  203 . The target BS list is acquired at the time the communication system first sets up the serving BS  200 , or is acquired from a BSC of the serving BS  200 . The serving BS  200  stores the target BS list in its RRC. Also, the serving BS  200  stores even its serving BS list. In this case, the serving BS  200  does not include information on a target BS  250  in the target BS list that it includes in a MOB_NBR-ADV message during its generation. 
         [0039]    Similarly, in step  201   b,  the target BS  250  also acquires a serving BS list. The serving BS list is also acquired at the time the communication system first sets up the target BS  250 , or is acquired from a BSC of the target BS  250 . The acquired serving BS list is stored in an RRC existing in the target BS  250 , and the target BS list of the target BS  250  is also stored. 
         [0040]    Although not illustrated in  FIGS. 2A and 2B , in a transmission period of the MOB_NBR-ADV message, the serving BS  200  periodically sends the MOB_NBR-ADV message to an MS(s). 
         [0041]    In step  203 , the serving BS  200  sends a Radio_Configuration_Update_Request (Radio_Config_Update_Req) message to the target BS  250 , one of neighbor BSs included in the target BS list, to acquire downlink channel descriptor (DCD) information and uplink channel descriptor (UCD) information of the target BSs included in the target BS list, and then proceeds to step  205 . The Radio_Config_Update_Req message can be sent at stated periods, or can be sent when necessary. 
         [0042]    Although it is assumed herein that the target BS list of the serving BS  200  has only one neighbor BS (i.e., target BS  250 ) for convenience, the same can be applied to each of a plurality of neighbor BSs when there are the plurality of neighbor BSs. 
         [0043]    In step  205 , the serving BS  200  starts a timer the moment that it sends the Radio_Config_Update_Req message. The serving BS  200  starts the timer to check if a response message to the Radio_Config_Update_Req message is received during a predetermined time. 
         [0044]    Upon receipt of the Radio_Config_Update_Req message, the target BS  250  sends in step  207  a Radio_Configuration_Update_Report (Radio_Config_Update_Rpt) message with DCD information and UCD information of the target BS  250  to the serving BS  200 . 
         [0045]    In step  209 , the serving BS  200  acquires information (i.e., DCD/UCD information) of the target BS  250  through the Radio_Config_Update_Rpt message sent by the target BS  250 . Thus, the serving BS  200  adds the acquired information of the target BS  250  to the target BS list in the MOB_NBR-ADV message, and resets the timer. 
         [0046]    In step  211 , the serving BS  200  sends to the target BS  250  a Radio_Configuration_Update_Confirm (Radio_Config_Update_Cnf) message indicating that it has normally received the Radio_Config_Update_Rpt message sent by the target BS  250 . 
         [0047]    Although not illustrated in  FIG. 2A , the target BS  250 , when DCD information or UCD information of the target BS  250  is changed, may send a Radio_Config_Update_Rpt message to the serving BS  200  even though it has not received from the serving BS  200  the Radio_Config_Update_Req message indicating a request for information of the target BS  250 . In this case, the target BS  250  marks the change of the DCD information or UCD information in a Change Configuration Count field. For example, ‘0’ indicating the non-change of the information or ‘1’ indicating the change of the information is written in the field. 
         [0048]      FIG. 2B  is a signaling diagram illustrating another exemplary process of updating neighbor BS information by a serving BS in a communication system according to an embodiment of the present invention. 
         [0049]    Referring to  FIG. 2B , in step  251   a,  a serving BS  200  generates a target BS list, and then proceeds to step  253 . The target BS list is acquired at the time the communication system first sets up the serving BS  200 , or is acquired from a BSC of the serving BS  200 . The serving BS  200  stores the target BS list in its RRC. Also, the serving BS  200  stores even its serving BS list. In this case, the serving BS  200  does not include information on a target BS  250  in the target BS list that it includes in a MOB_NBR-ADV message during its generation. 
         [0050]    Similarly, in step  251   b,  the target BS  250  also acquires a serving BS list. The serving BS list is also acquired at the time the communication system first sets up the target BS  250 , or is acquired from a BSC of the target BS  250 . The acquired serving BS list is stored in an RRC existing in the target BS  250 , and the target BS list of the target BS  250  is also stored. 
         [0051]    In step  253 , the serving BS  200  sends a Radio_Config_Update_Req message to the target BS  250 , one of the neighbor BSs included in the target BS list, to acquire DCD information and UCD information of the neighbor BSs included in the acquired target BS list, and then proceeds to step  255 . The Radio_Config_Update_Req message can be sent at stated periods, or can be sent when necessary. 
         [0052]    Although it is assumed herein that the target BS list of the serving BS  200  has only one neighbor BS (i.e., target BS  250 ) for convenience, the same can be applied to each of a plurality of neighbor BSs when there are the plurality of neighbor BSs. 
         [0053]    In step  255 , the serving BS  200  starts a first timer the moment that it sends the Radio_Config_Update_Req message. The serving BS  200  starts the first timer to check if a response message to the Radio_Config_Update_Req message is received during a predetermined time. After the first timer expires in step  257  as the predetermined time has elapsed, if the serving BS  200  has failed to receive a response message to the Radio_Config_Update_Req message, it resends the Radio_Config_Update_Req message to the target BS  250  in step  259 . 
         [0054]    In step  261 , the serving BS  200  restarts the first timer. After the first timer is restarted, the target BS  250 , which has received the Radio_Config_Update_Req message, sends in step  263  a Radio_Config_Update_Rpt message with DCD information and UCD information of the target BS  250  to the serving BS  200 . 
         [0055]    In step  265 , the target BS  250  starts a second timer the moment that it sends the Radio_Config_Update_Rpt message to the serving BS  200 . The target BS  250  starts the second timer to check if a response message indicating the normal receipt of the Radio_Config_Update_Rpt message is received during a predetermined time. 
         [0056]    In step  267 , the serving BS  200  acquires information (i.e., DCD/UCD information) of the target BS  250  through the Radio_Config_Update_Rpt message sent by the target BS  250 . Thus, the serving BS  200  adds the information of the target BS  250  to the MOB_NBR-ADV message, and resets the first timer. 
         [0057]    In step  269 , the serving BS  200  sends to the target BS  250  a Radio_Config_Update_Cnf message indicating the normal receipt of the Radio_Config_Update_Rpt message sent by the target BS  250 . The Radio_Config_Update_Rpt message includes parameters such as a preamble index, Handover Process Optimization, Mobility Feature Support, Phy Mode ID, and Scheduling Service Supported. 
         [0058]    Thereafter, the target BS  250  receives the Radio_Config_Update_Cnf message from the serving BS  200 , and resets the second timer in step  271 . 
         [0059]    Although not illustrated in  FIG. 2B , if the serving BS  200  fails to receive a Radio_Config_Update_Rpt message from the target BS  250  before the expiration of the second timer even though it has resent the Radio_Config_Update_Req message to the target BS  250  a predetermined number of times, the serving BS  200  deletes the identifier and information of the target BS  250  from the acquired serving BS list. 
         [0060]    Meanwhile, if the target BS  250  cannot occasionally remember the previous history such as a power off (i.e., information indicating from which serving BS the Radio_Config_Update_Req message was received), the target BS  250  may suffer a time delay in synchronizing the lost information. However, since the proposed target BS  250 , like the serving BS  200 , acquires and stores the serving BS list, if the target BS  250  perceives a change of its information (i.e., DCD information and UCD information), it sends a Radio_Config_Update_Rpt message with its changed DCD information and UCD information to a BS included in the serving BS list (e.g., the serving BS  200 ) regardless of the receipt of a Radio_Config_Update_Req message from the serving BS  200 . 
         [0061]      FIG. 3  is a flowchart illustrating an operation of a serving BS in a communication system according to an embodiment of the present invention. 
         [0062]    Referring to  FIG. 3 , in step  301 , the serving BS generates a target BS list, and then proceeds to step  303 . The target BS list is acquired at the time the communication system first sets up the serving BS, or is acquired from a BSC of the serving BS. In this case, the serving BS does not include information on a desired target BS in the target BS list that it includes in a MOB_NBR-ADV message during its generation. In step  303 , the serving BS sends a Radio_Config_Update_Req message to the target BS to acquire information of the target BS, and starts a timer. In step  305 , the serving BS checks if it has received a Radio_Config_Update_Rpt message from the target BS. If it is determined that the serving BS has received the Radio_Config_Update_Rpt message, it proceeds to step  307 . However, if it is determined that the serving BS has not received the Radio_Config_Update_Rpt message, it proceeds to step  309 . 
         [0063]    In step  307 , the serving BS, which has received the Radio_Config_Update_Rpt message in step  305 , acquires information of the target BS included in the received Radio_Config_Update_Rpt message, adds the acquired target BS&#39;s information to the MOB_NBR-ADV message, and resets a timer. In step  311 , the serving BS sends to the target BS a Radio_Config_Update_Cnf message indicating the normal receipt of the Radio_Config_Update_Rpt message sent by the target BS, and then ends the procedure. The Radio_Config_Update_Rpt message includes parameters such as a preamble index, Handover Process Optimization, Mobility Feature Support, Phy Mode ID, and Scheduling Service Supported. 
         [0064]    If it is determined in step  305  that the serving BS has not received the Radio_Config_Update_Rpt message, the serving BS checks in step  309  if timer has expired. If it is determined that the timer has expired, the serving BS returns to step  303  where it resends the Radio_Config_Update_Req message to the target BS and repeats the same procedure. 
         [0065]    However, if it is determined in step  309  that the timer has not expired, the serving BS returns to step  305  where the serving BS checks if it has received the Radio_Config_Update_Rpt message from the target BS and repeats the same procedure. 
         [0066]      FIG. 4  is a flowchart illustrating an operation of a target BS in a communication system according to an embodiment of the present invention. 
         [0067]    Referring to  FIG. 4 , in step  401 , the target BS acquires a serving BS list at the time the communication system first sets up the neighbor BS, or acquires a serving BS list from its BSC. The target BS stores the serving BS list in its RRC. 
         [0068]    In step  403 , the target BS receives a Radio_Config_Update_Req message from a serving BS. Thereafter, if the target BS perceives a change in its information (i.e., DCD information and UCD information), the target BS sends a Radio_Config_Update_Rpt message to the serving BS and starts a timer in step  405 . 
         [0069]    Since the target BS acquires and stores the serving BS list, if the target BS perceives a change of its information (i.e., DCD information and UCD information), it sends a Radio_Config_Update_Rpt message with its changed DCD information and UCD information to BSs included in the serving BS list, regardless of the receipt of a Radio_Config_Update_Req message from the serving BS. 
         [0070]    In step  407 , the target BS checks if it has received a Radio_Config_Update_Cnf message from the serving BS. If it is determined that the target BS has received the Radio_Config_Update_Cnf message, the target BS proceeds to step  411 . However, if it is determined that the target BS has not received the Radio_Config_Update_Cnf message, the target BS proceeds to step  409 . The Radio_Config_Update_Rpt message includes parameters such as a preamble index, Handover Process Optimization, Mobility Feature Support, Phy Mode ID, and Scheduling Service Supported. 
         [0071]    Upon receiving the Radio_Config_Update_Cnf message in step  407 , the target BS proceeds to step  411  where it resets the timer and ends the procedure. 
         [0072]    However, upon failure to receive the Radio_Config_Update_Cnf message in step  407 , the target BS proceeds to step  409  where it checks if the timer has expired. If it is determined that the timer has expired, the target BS returns to step  405  where it resends the Radio_Config_Update_Rpt message to the serving BS and repeats the same procedure. 
         [0073]    On the other hand, if it is determined that the timer has not expired, the target BS returns to step  407  where the target BS checks if it has received the Radio_Config_Update_Cnf message from the serving BS, and repeats the same procedure. 
         [0074]    As is apparent from the foregoing description, the present invention additionally suggests the Radio_Config_Update_Cnf message indicating the completed update of neighbor BS information when the serving BS exchanges messages to update the neighbor BS information in the communication system, thereby matching the neighbor BS information managed by the serving BS and the target BS. In addition, since the target BS has the serving BS list, the target BS, when its state is changed (e.g., a change in DCD/UCD message or BS restart), transmits the changed information (DCD/UCD) to the serving BS anytime, thus preventing generation of the traffic unnecessary for the network and contributing to a reduction in the time required for updating the neighbor information (DCD/UCD). 
         [0075]    Although the present disclosure has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present disclosure encompass such changes and modifications as fall within the scope of the appended claims.