WO2009069927A2

WO2009069927A2 - Method and apparatus for paging in wireless communication system

Info

Publication number: WO2009069927A2
Application number: PCT/KR2008/006942
Authority: WO
Inventors: Su Lyun Sung; Dong Hyun Lee
Original assignee: Posdata Co., Ltd.
Priority date: 2007-11-26
Filing date: 2008-11-26
Publication date: 2009-06-04
Also published as: WO2009069927A3; KR20090054037A

Abstract

A method and apparatus for paging in a wireless communication system is disclosed, which is capable of performing the paging for a plurality of paging groups by detecting a tendency in movement of an MS, wherein the method comprises detecting the number of paging groups with reference to a database recording information of BS changed according to a movement of an MS and information of paging group including the BS; and sequentially performing the paging for the BS corresponding to the information of BS recorded in the database if the number of paging groups is more than a reference value.

Description

METHOD AND APPARATUS FOR PAGING IN WIRELESS COMMUNICATION SYSTEM

Technical Field

[1] The present invention relates to a wireless communication system, and more particularly, to a method and apparatus for paging in a wireless communication system. Background Art

[2] A procedure for calling a mobile station (hereinafter, referred to as 'MS') to transmit data thereto or to detect a location thereof in a wireless communication system is referred to as a paging. This paging is performed while dividing a service area into a plurality of paging zones. In this case, the paging zone indicates a predetermined area including a plurality of base stations (hereinafter, referred to as 'BS').

[3] FIG. 1 is a schematic view illustrating a general wireless communication system for performing the paging.

[4] Hereinafter, terms to be described are explained based on Wibro, WiMAX Forum

Network Architecture, or IEEE 802.16 technology standard.

[5] The wireless communication system shown in FIG. 1 is managed by one access service network (hereinafter, referred to as 'ASN', not shown). The wireless communication system includes a location register (hereinafter, referred to as 'LR') 102 having information about an idle-mode MS, a paging controller (hereinafter, referred to as 'PC) 104 for managing an operation of the idle-mode MS, and BSs 106, 108, and 110.

[6] When performing the paging, the BSs 106, 108, and 110 function as paging agents

(hereinafter, referred to as 'PA') 106, 108, and 110 for performing paging-related functions; and paging groups 112, 114, and 116 indicate groups of PAs 106, 108, and 110, that is, groups of BSs 106, 108, and 110.

[7] Referring to FIG. 1, the first BS 106 is mapped to the first paging group 112 with a paging group identifier (hereinafter, referred to as 'PGID') of "PGID(I)"; and the second BS 108 may be mapped to the first or second paging group 112 or 114. Also, the first PC 104 manages the paging for the two paging groups 112 and 114.

[8] FIGs. 2 and 3 illustrate the general paging algorithm, wherein FIG. 2 illustrates a single-step paging method, and FIG. 3 illustrates a multi-step paging method.

[9] Referring to FIG. 2, the paging group (not shown) may be divided into a plurality of sub-groups 204, 206, and 208. In the single-step paging method, an anchor paging controller (hereinafter, referred to as 'anchor PC) 202 transmits a paging announcement message (hereinafter, referred to as 'Paging_Announce message') to BSs (not shown) included in all sub-groups 204, 206, and 208 at a predetermined time point. At this time, the Paging_Announce message may be transmitted to the BSs through a relay paging controller (hereinafter, referred to as 'relay PC, not shown).

[10] Referring to FIG. 3, in the case of multi-step paging method, an anchor PC 302 transmits a Paging_Announce message to a sub-group 304 including a final serving BS; and then gradually extends the area for paging to the other sub-groups 306 and 308 until receiving a response from an MS.

[11] In the case of single-step paging method, the paging procedure is performed for all

BSs included in the paging group, thereby wasting a large amount of radio resources. However, if decreasing the area of paging groups so as to reduce the consumption of radio resources, the MS has to update its location frequently, thereby causing a problem of low response ratio of the MS according to the paging procedure.

[12] In the case of multi-step paging method, the area for paging is gradually extended so that it is possible to overcome the problem such as the consumption of radio resources which occurs in the single-step paging method. However, the conventional multi-step paging method does not regulate a method of performing the paging for the plurality of paging groups.

[13] If the MS is moved among the BSs included in the different paging groups within the large area, a probability of detecting the MS is lowered remarkably. In this case, the paging may be performed for all sub-groups, thereby causing the increase of delay time and wasting a large amount of radio resources.

Disclosure of Invention

Technical Problem

[14] Therefore, the present invention has been made in view of the above problems, and it is an object of the present invention to provide a method and apparatus for paging in a wireless communication system, which is capable of preventing one or more problems of the related art. [15] Another object of the present invention is to provide a method and apparatus for paging in a wireless communication system, which can use a tendency in movement of an MS. [16] Another object of the present invention is to provide a method and apparatus for paging in a wireless communication system, which is capable of performing a paging for a plurality of paging groups.

Technical Solution [17] To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a method for paging in a wireless communication system comprises detecting the number of paging groups with reference to a database recording information of BS changed according to a movement of an MS and information of paging group including the BS; and sequentially performing the paging for the BS corresponding to the information of BS recorded in the database if the number of paging groups is more than a reference value.

[18] In another aspect of the present invention, a method for paging in a wireless communication system comprises selecting a target MS to be transmitted a paging message if a paging start condition is satisfied; performing the paging for paging groups if the number of paging groups mapped to paging group information corresponding to the target MS recorded in a database is "2" or more, wherein the database is recorded with one or more entries including information of serving BS changed according to a movement of an MS for a predetermined time period and information of paging group mapped to the information of serving BS.

[19] In another aspect of the present invention, an apparatus for paging in a wireless communication system comprises means for managing an MS-status information to determine whether or not information of BS and information of paging group including the BS are changed according to a movement of an MS; means for managing an MS location table to record the changed information of BS and paging group in a database when it is determined that the information of BS and paging group are changed; and paging performing means configured to detect the number of paging groups recorded in the database with reference to the database, and to sequentially perform the paging for the BS corresponding to the information of BS recorded in the database when the number of paging groups is more than a reference value.

Advantageous Effects

[20] According to the present invention, it is possible to perform the paging by using the tendency in movement of the MS, thereby resulting in the improved probability of detecting the MS. Thus, the radio resources and time used for the paging can be reduced.

[21] Also, the paging can be performed for the plurality of paging groups, whereby it is possible to improve the probability of detecting the MS which moves in the wide area, and to reduce the consumption of radio resources and the time delay. Brief Description of Drawings

[22] FIG. 1 is a schematic view illustrating a general wireless communication system for performing a paging.

[23] FIGs. 2 and 3 are schematic views illustrating a general paging algorithm.

[24] FIG. 4 is a block diagram illustrating a paging apparatus in a wireless communication system according to one embodiment of the present invention.

[25] FIG. 5 is a diagram illustrating an MS location table according to one embodiment of the present invention.

[26] FIG. 6 is a diagram illustrating a paging group to be a moving path of an MS shown in an MS location table, and sub-groups included in each paging group.

[27] FIG. 7 is a flow chart illustrating a paging method in a wireless communication system according to one embodiment of the present invention. Mode for the Invention

[28] Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

[29] Hereinafter, a method and apparatus for paging in a wireless communication system according to the present invention will be explained with reference to the accompanying drawings.

[30] FIG. 4 is a block diagram illustrating a paging apparatus in a wireless communication system according to one embodiment of the present invention.

[31] As shown in FIG. 4, the paging apparatus 400 in the wireless communication system according to one embodiment of the present invention determines a paging method by detecting a tendency in movement of an MS, and performs a paging procedure based on the determined result. The paging apparatus 400 includes determining means for triggering paging 402, means for updating a location 404, means for managing MS- status information 406, means for managing an MS location table 408, and paging performing means 410.

[32] The paging apparatus 400 may be an apparatus included in a paging controller

(hereinafter, referred to as 'PC), or an apparatus separated from the PC.

[33] When there is downlink data traffic to be transmitted to the MS, or the determining means for triggering paging 402 receives a paging request for a location update of the MS from the means for updating a location 404, the determining means for triggering paging 402 transmits a request to determine whether or not the paging is possible to the means for managing MS-status information 406. Then, the determining means for triggering paging 402 receives the determined result related with whether or not the paging is possible from the means for managing MS-status information 406. When it is determined that the paging is possible, the determining means for triggering paging 402 transmits a paging start request to the paging performing means 410.

[34] The means for updating a location 404 receives a location update request of an MS in an idle mode, and processes the location update request. Also, the means for updating a location 404 requests the paging of the determining means for triggering paging 402 when an error condition such as expiration of an idle mode system timer is satisfied. [35] At this time, the location update request of the MS indicates a request for periodically updating location information of the MS every predetermined time period, or a request for updating location information of the MS when the MS moves out of a paging group. This periodic location update and the location update based on the paging group enable the MS to be successfully provided with a paging service by maintaining updated information about the MS.

[36] The means for managing MS-status information 406 records and manages the information about the MS in the idle mode. Also, the means for managing MS-status information 406 determines whether or not information about a BS and information about a paging group including the BS are changed according to the movement of the MS. At this time, the information about the MS according to the movement of the MS may be an ID of serving BS (BS ID), which is recorded when the MS in the idle mode enters a network or the location of the MS is updated. Also, the information about the paging group including the BS may be an ID of paging group (PG ID) including the serving BS.

[37] When the ID of serving BS or the ID of paging group including the serving BS is changed according to the movement of the MS, the means for managing MS-status information 406 transmits the changed ID of serving BS or the changed ID of paging group to the means for managing an MS location table 408.

[38] When receiving the request to determine whether or not the paging is possible from the determining means for triggering paging 402, the means for managing MS-status information 406 transmits the determined result related with whether or not the paging is possible to the determining means for triggering paging 402. In one embodiment of the present invention, whether or not the paging is possible is determined based on paging preference or paging policy of corresponding wireless communication system.

[39] If there is no response from the MS after performing all steps of the paging procedure, the means for managing MS-status information 406 deletes the information about the MS.

[40] When receiving the ID of serving BS changed according to the movement of the MS or the ID of paging group including the changed serving BS from the means for managing MS-status information 406, the means for managing an MS location table 408 records the received information in a database (not shown). This database will be referred to as a MS location table. Herein, if there is no MS location table, the MS location table is newly created, and then the received information is recorded in the newly-created MS location table.

[41] FIG. 5 illustrates the MS location table according to one embodiment of the present invention.

[42] As shown in FIG. 5, the MS location table 502 is a database which defines the ID of serving BS changed according to the movement of the MS and the ID of paging group including the changed serving BS as one entry. For example, three entries 504, 506, and 508 are recorded for recent twelve hours.

[43] At this time, the entries 504, 506, and 508 of the MS location table 502 are recorded by FILO (first-in last-out). This is to make a sequential reference from the entry 508 lately recorded during performing the paging. At this time, the entry 504 lately recorded in the MS location table 502 has "BSID30" corresponding to the ID of BS, and "PGIDl" corresponding to the ID of paging group. That is, the final serving BS has "BSID30" corresponding to the ID of BS, and the final serving BS is included in the paging group having "PGIDl" corresponding to the ID of paging group.

[44] The entry is recorded in the MS location table 502 when information included in the entry is different from information included in an entry previously recorded in the MS location table 502. That is, if the ID of serving BS and the ID of paging group including the serving BS, which are received from the means for managing MS-status information 406, correspond to the information already recorded in the MS location table 502, there is no need for the additional record. Because paging is sequentially performed to the respective BSs mapped to the entries 504, 506, and 508 of the MS location table 502, it is possible to prevent the paging from being repeatedly performed for the same area.

[45] When detecting the tendency in movement of the MS with reference to the MS location table 502, it is known that the MS is moved from the BS with "BSIDlO" included in the paging group with "PGIDl" to the BS with "BSID20" included in the paging group "PGID2", and is then moved to the BS with "BSID30" included in the paging group with "PGIDl", for the recent twelve hours.

[46] In the aforementioned embodiment of the present invention, the size of MS location table 502 is determined on the basis of the predetermined time period, that is, twelve hours. In a modified embodiment of the present invention, the size of MS location table 502 may be determined on the basis of the specific number of entries. For example, on the assumption that the MS location table 502 can have the three entries, if the means for managing an MS location table 408 receives the ID of BS newly changed according to the movement under circumstances where the three entries are recorded in the MS location table 502, or the ID of paging group including the changed BS, the entry firstly recorded in the MS location table 502 is deleted, and the newly received entry can be recorded in the MS location table 502.

[47] The size of MS location table 502 is determined on the basis of the predetermined time period or the specific number of entries. This enables detecting the tendency in current movement of the MS through the use of record of information about the BS to which the MS is moved for the predetermined time period, or information about the specific number of BSs among which the MS is moved by maintaining the MS location table 502 having the specific number of entries.

[48] Referring one again to FIG. 4, when receiving the paging start request from the determining means for triggering paging 402, the paging performing means 410 determines the paging method, and performs the paging procedure based on the determined paging method.

[49] In particular, if the number of paging groups having the different PGIDs recorded in the MS location table 502 is the same as or more than a predetermined reference value, the paging performing means 410 obtains the ID of corresponding BS and the ID of paging group including the corresponding BS from the means for managing an MS location table 408, and then sequentially performs the paging procedure for the BS with the corresponding ID of BS until there is the response from the MS.

[50] Hereinafter, the detailed paging method of the paging performing means 410 will be explained with reference to the MS location table 502 shown in FIG. 5.

[51] First, the paging performing means 410 determines whether the number of paging groups recorded in the MS location table 502 is the same as or more than the reference value with reference to the MS location table 502. At this time, since "PGIDl" and "PGID2" are recorded in the MS location table 502, it is known that the recorded number of paging groups is "2". If the reference value is "2", it satisfies that the recorded number of paging groups is the same as or more than the reference value. Thus, the paging performing means 410 sequentially performs the paging procedure starting from the BS corresponding to the ID of BS most-currently recorded in the MS location table 502.

[52] At this time, the BS to be a first target of paging is mapped to the third entry 504 lately recorded in the MS location table 502. While the BS to be the first target of paging has "BSID30", the BS to be the first target of paging is included in the paging group with "PGIDl".

[53] Also, the BS to be a second target of paging is mapped to the second entry 506.

While the BS to be the second target of paging has "BSID20", the BS to be the second target of paging is included in the paging group with "PGID2".

[54] Also, the BS to be a third target of paging is mapped to the first entry 508. While the

BS to be the third target of paging has "BSIDlO", the BS to be the third target of paging is included in the paging group with "PGIDl".

[55] In one embodiment of the present invention, when performing the paging procedure for each BS by the aforementioned method, it is possible to simultaneously perform the paging procedure for the other BSs included in a sub-group mapped to each BS. Since the paging group can be divided into the plurality of sub-groups, and each sub-group can include the plurality of BSs, a paging area is extended to the entire sub-group including the paging-targeted BS, to thereby improve a probability of detecting the MS. This will be explained with reference to FIG. 6.

[56] FIG. 6 illustrates the paging group to be a moving path of the MS shown in the MS location table 502 of FIG. 5, and sub-groups included in each paging group.

[57] The paging group 602 with "PGIDl" has two sub-groups 606 and 608, and the paging group 604 with "PGID2" has one sub-group 610.

[58] From explanation using the MS location table 502 of FIG. 5, if the paging is performed for the BS with "BSID30" included in the sub-group 608, the paging is also performed for the other BSs with "BSID31" and "BSID32" included in the sub-group 608, simultaneously. If there is no response from the MS, the paging is performed for the BS with "BSID20" included in the sub-group 610, whereby the paging is also performed for the other BSs included in the sub-group 610 mapped to the BS with "BSID20". Next, when performing the paging for the BS with "PGIDlO" included in the sub-group 606, the paging is also performed for the other BSs included in the subgroup 606 mapped to the BS with "BSIDlO".

[59] In another embodiment of the present invention, when performing the paging for each BS, the paging can be simultaneously performed for all other BSs within a predetermined distance from the targeted BS. According as the paging area is extended to the other BSs within the predetermined distance from the targeted BS, it is possible to improve the probability of detecting the MS.

[60] In another embodiment of the present invention, when performing the paging for each BS, the paging can be simultaneously performed for all other BSs included in the paging group of the targeted BS. At this time, the paging is not performed repeatedly for the same paging group.

[61] Referring one again to FIG. 4, if the reference value is "2", and the number of paging groups recorded in the MS location table 502 is "1", the paging performing means 410 performs the paging procedure based on the multi-step paging method.

[62] In order to perform the multi-step paging method, the paging performing means 410 obtains the ID of final serving BS updated in the means for managing MS-status information 406, or the ID of BS lately recorded in the MS location table 502. Then, the paging performing means 410 firstly performs the paging for the sub-group mapped to the BS corresponding to the obtained ID of BS. If there is no response from the MS, the paging area is gradually extended to the next sub-group according to the predetermined condition.

[63] In a modified embodiment of the present invention, the paging performing means

410 may use the single-step paging method if the number of paging groups recorded in the MS location table 502 is less than the reference value.

[64] The paging performing means 410 creates a Paging_Announce message for the BS selected as a target of paging according to the aforementioned method, and sequentially transmits the created Paging_Announce message until there is the response from the MS. In one embodiment of the present invention, the Paging_Announce message may be transmitted to the BS by a Relay PC.

[65] Among the aforementioned embodiments of the present invention, one embodiment of the present invention discloses that the paging apparatus of the wireless communication system is comprised of the plurality of separate units. However, the modified embodiment of the present invention discloses that the units included in the paging apparatus of the wireless communication system may be integrated into one, or some of the units included therein may be integrated into one.

[66] FIG. 7 is a flow chart illustrating the paging method in the wireless communication system according to one embodiment of the present invention.

[67] First, the database with the information about the BS changed according to the movement of the MS and the information about the paging group including the BS is maintained in step of S702. Hereinafter, the database will be referred to as the MS location table.

[68] In the MS location table, the information about the BS changed according to the movement of the MS and the information about the paging group including the BS are defined as one entry. Hereinafter, one exemplary case, which illustrates that the information about the BS is the ID of BS, and the information about the paging group is the ID of paging group, will be explained as follows.

[69] Only if the corresponding entry comprised of both the ID of BS changed according to the movement of the MS and the ID of paging group including the BS is not recorded in the MS location table, the corresponding entry is newly added to the MS location table. Because the paging is sequentially applied to the entries of the MS location table one by one, it is possible to prevent the paging from being repeatedly performed for the same area.

[70] The entries are recorded in the MS location table for the predetermined time period or within the range of specific number. This is for detecting the tendency in current movement of the MS through the use of record of information about the BS to which the MS is moved for the predetermined time period, or information about the specific number of BSs among which the MS is moved by maintaining the MS location table having the specific number of entries.

[71] The entries are recorded in the MS location table by FILO. This is to make the sequential reference from the entry lately recorded during performing the paging.

[72] Next, it is determined whether or not the MS location update condition is satisfied in step of S704a, or whether or not downlink data traffic is generated in step of 704b.

[73] When receiving the request for periodically updating the location information from the MS, or receiving the request for updating the location information from the MS in case the MS moves out of the paging group, the MS location update condition can be satisfied.

[74] When it is determined that the downlink data traffic is generated, it is determined whether or not the paging preference is "1" in step of S706. When the paging preference is " 1", the following steps for performing the paging are carried out. In the meantime, when the paging preference is "0", the procedure is completed without carrying out the following steps for performing the paging.

[75] When it is determined that the MS location update condition is satisfied in step of

S704a, or the downlink data traffic is generated in step of S704b, that is, when it is determined that the downlink data traffic is generated and the paging preference is " 1", it is determined whether or not the number of paging groups having the different paging group information recorded in the MS location table is the same as or more than the reference value in step of S708.

[76] For example, on the assumption that the reference value is "2", if the number of paging groups recorded in the MS location table is "2", it is determined that the number of paging groups is the same as or more than the reference value.

[77] Based on the determined result, if the number of paging groups having the different

PGIDs recorded in the MS location table is the same as or more than the reference value, the ID of BS most-currently recorded in the MS location table and the ID of paging group including the BS are obtained from the MS location table, and the BS with the obtained ID of BS is selected sequentially until there is the response from the MS in step of S710a.

[78] The step S710a of selecting the BS to be a target of paging by using the MS location table and the following steps thereof will be explained in detail. First, the BS with the ID of BS most-currently recorded in the MS location table is selected firstly. At this time, the firstly-selected BS is to be mapped to the entry lately recorded in the MS location table.

[79] After that, the Paging_Announce message is created and is then transmitted to the firstly-selected BS, whereby the paging is performed in step of S712. In one embodiment of the present invention, the Paging_Announce message can be simultaneously transmitted to all BSs included in the same sub-group mapped to the firstly- selected BS. At this time, the paging group may be divided into the plurality of subgroups, and each sub-group includes the plurality of BSs. Thus, the paging area is extended to the entire sub-group including the firstly- selected BS, to thereby improve the probability of detecting the MS.

[80] In the modified embodiment of the present invention, the paging can be simultaneously performed for all other BSs within the predetermined distance from the firstly-selected BS. According as the paging are is extended to the other BSs within the predetermined distance from the firstly-selected BS, it is possible to improve the probability of detecting the MS.

[81] In one embodiment of the present invention, the Paging_Announce message can be transmitted to the BSs by the Relay PC.

[82] After that, it is determined whether there is the response from the MS in step of

S714. When there is no response from the MS, the BS to be the next target of paging is selected from the MS location table in step of S710a.

[83] At this time, since there is no response from the MS after performing the paging for the BS with the ID of BS lately recorded in the MS location table, the next BS is determined as the secondly-selected BS with the ID of BS secondly-recorded in the MS location table, which is coming after the lately- selected BS.

[84] After that, the paging is performed by transmitting the Paging_Announce message to the secondly- selected BS in step of S712. Also, it is determined whether there is the response from the MS in step of S714, and the aforementioned steps are performed repeatedly.

[85] In one embodiment of the present invention, if there is no response from the MS after performing the paging procedure for all BSs selected from the MS location table, the information about the MS can be deleted.

[86] According to the determined result of S706, if the number of paging groups having the different PGIDs recorded in the MS location table is not the same as or more than the reference value, the BS to be the target of paging by the multi-step paging method and the sub-group including the targeted BS are selected in step of S710b.

[87] For example, supposing that the reference value is "2", and the number of paging groups having the different PGIDs recorded in the MS location table is "1". Since the number of paging groups is less than the reference value, the BS to be the target of paging by the multi-step paging method and the sub-group including the targeted BS are selected.

[88] In one embodiment of the present invention, the BS to be the target of paging may correspond to the BS which is provided with the ID of final serving BS updated, or the BS which is provided with the ID of BS lately recorded in the MS location table.

[89] After that, the paging is firstly performed for the selected sub-group in step of S712, and then it is determined whether there is the response fro the MS in step of S714. If there is no response from the MS, the next sub-group is selected according to the predetermined condition in step of S710b. Then, the paging area is gradually extended according to whether there is the response from the MS.

[90] In the modified embodiment of the present invention, the paging procedure can be performed by the single-step paging method instead of the multi-step paging method. [91] As mentioned above, if the MS is moved among the different paging groups, the paging procedure is performed for the selected BS by using the MS location table in which the tendency in movement of the MS is recorded. Thus, it is possible to decrease the consumption of radio resources and time and to improve the probability of detecting the MS. If the MS is moved within the range of the same paging group, the paging procedure is performed for the BS by the multi-step paging method or single- step paging method, thereby preventing the consumption of radio resources.

[92] It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions.

[93] For example, in the aforementioned embodiment of the present invention, the paging method is determined based on the number of paging groups having the different PGIDs with reference to the database including the ID of BS changed according to the movement of the MS and the ID of paging group including the BS. In the modified embodiment of the present invention, the paging procedure can be sequentially performed for the BS with the ID of BS recorded in the database.

[94] Thus, it should be understood that the aforementioned embodiments of the present invention are for purpose of illustration, and are not to be constructed as limitations of the invention. It is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

[95]

[96]

Claims

[1] A method for paging in a wireless communication system comprising: detecting the number of paging groups with reference to a database recording information of BS changed according to a movement of an MS and information of paging group including the BS; and sequentially performing the paging for the BS corresponding to the information of BS recorded in the database if the number of paging groups is more than a reference value.

[2] The method of claim 1, wherein the information of BS and the information of paging group are recorded in the database for a predetermined time period or within a range of specific number.

[3] The method of claim 1, wherein the information of BS and the information of paging group are defined as one entry in the database, wherein, when the entry including the information of BS and the information of paging group does not correspond to an entry already recorded in the database, the entry including the information of BS and the information of paging group is newly added to the database.

[4] The method of claim 1, wherein the paging is sequentially performed starting from the paging group corresponding to the information of the BS lately recorded in the database in the step of performing the paging.

[5] The method of claim 1, wherein the paging is simultaneously performed for other

BSs included in a sub-group mapped to the BS to be a target of paging in the step of performing the paging, wherein the sub-group is among the plurality of sub-groups constituting the paging group.

[6] The method of claim 1, wherein the paging is simultaneously performed for other

BSs positioned within a predetermined distance from the BS to be a target of paging in the step of performing the paging.

[7] The method of claim 1, further comprising: deleting information of the MS if there is no response from the MS, whereas performing the paging until there is the response from the MS.

[8] The method of claim 1, further comprising: performing a paging based on a single-step or multi-step paging method, if the number of paging groups is less than the reference value.

[9] The method of claim 1, wherein the information of BS is an ID of BS, and the information of paging group is an ID of paging group.

[10] A method for paging in a wireless communication system comprising: selecting a target MS to be transmitted a paging message if a paging start condition is satisfied; performing the paging for paging groups if the number of paging groups mapped to paging group information corresponding to the target MS recorded in a database is "2" or more, wherein the database is recorded with one or more entries including information of serving BS changed according to a movement of an MS for a predetermined time period and information of paging group mapped to the information of serving BS.

[11] The method of claim 10, wherein the paging is sequentially performed for the entries until receiving a paging response from the target MS in the step of performing the paging.

[12] The method of claim 10, further comprising: performing a paging based on a single-step or multi-step paging method, if the number of paging groups is " 1 ".

[13] The method of claim 10, wherein the paging start condition is whether there is downlink data traffic for the target MS or whether a location update request is received from the target MS.

[14] An apparatus for paging in a wireless communication system comprising: means for managing an MS-status information to determine whether or not information of BS and information of paging group including the BS are changed according to a movement of an MS; means for managing an MS location table to record the changed information of BS and paging group in a database when it is determined that the information of BS and paging group are changed; and paging performing means configured to detect the number of paging groups recorded in the database with reference to the database, and to sequentially perform the paging for the BS corresponding to the information of BS recorded in the database when the number of paging groups is more than a reference value.

[15] The apparatus of claim 14, wherein the means for managing an MS location table records the information of BS and paging group in the database for a predetermined time period or within a range of specific number.

[16] The apparatus of claim 14, wherein the means for managing an MS location table records the information of BS and paging group in the database by First In Last Out (FILO).

[17] The apparatus of claim 14, wherein the means for managing an MS location table defines the information of BS and paging group as an entry in the database.

[18] The apparatus of claim 17, wherein the means for managing an MS location table adds the entry including the information of BS and paging group as a new entry in the database when the entry including the information of BS and paging group does not correspond to an entry already recorded in the database.

[19] The apparatus of claim 14, wherein the paging performing means sequentially performs the paging starting from the paging group corresponding to the information of BS lately recorded in the database.

[20] The apparatus of claim 14, wherein the paging performing means simultaneously performs the paging for other BSs included in a sub-group mapped to the BS to be a target of paging among the plurality of sub-groups included in the paging group when performing the paging for the BS corresponding to the information of BS.

[21] The apparatus of claim 14, wherein the paging performing means simultaneously performs the paging for other BSs positioned within a predetermined distance from the BS to be a target of paging when performing the paging for the BS corr esponding to the information of BS.

[22] The apparatus of claim 14, wherein the paging performing means performs the paging until there is a response from the MS, and deletes information of the MS when there is no response from the MS.

[23] The apparatus of claim 14, wherein the paging performing means performs a paging based on a single-step or multi-step paging method if the number of paging groups is less than the reference value.

[24] The apparatus of claim 14, wherein the information of BS is an ID of BS, and the information of paging group is an ID of paging group.

[25] The apparatus of claim 14, further comprising: determining means for triggering paging configured to requesting the paging to the paging performing means when downlink data traffic is generated or paging request for a location update of the MS is received therein.