Title of Invention	SUPPORTING IDLE MODE OF MOBILE STATION IN WIRELESS ACCESS SYSTEM"
Abstract	A method of supporting a mobile station that is in idle mode in a wireless communication system using a paging controller comprises entering an idle mode by a mobile station, receiving a paging command from a base station in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the base station in response to paging announcement from the paging controller, and existing the idle mode and establishing communication with one of the plurality of base stations, wherein the plurality of base stations in the same paging group receive an idle mode exist status from the paging controller.

Title of Invention

SUPPORTING IDLE MODE OF MOBILE STATION IN WIRELESS ACCESS SYSTEM"

Abstract

A method of supporting a mobile station that is in idle mode in a wireless communication system using a paging controller comprises entering an idle mode by a mobile station, receiving a paging command from a base station in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the base station in response to paging announcement from the paging controller, and existing the idle mode and establishing communication with one of the plurality of base stations, wherein the plurality of base stations in the same paging group receive an idle mode exist status from the paging controller.

Full Text	SUPPORTING IDLE MODE OF MOBILE STATION IN WIRELESS ACCESS SYSTEM (Description] TECHNICAL FIELD The present invention relates generally to a wireless access system and, more particularly, to idle mode of a mobile station in a wireless access system. BACKGROUND ART Broadband wireless access systems typically support an idle-mode to minimize the power consumption of a mobile subscriber station (MSS). During the idle-mode, the MSS docs not perform a handover procedure when moving between base stations in the same paging zone. Therefore, the MSS does not need to transmit uplink information for the handover procedure, which'reduces corresponding power consumption. A paging zone is defined as a zone that is controlled by a plurality of base stations called a paging group. Each of the base stations in the paging group has the same p;i(',in;', i yi'lc (I'ni'.ing Cycle) ami the same paging offset (Paging OHsd). The MSS may make a request to a base station to switch to the idle-mode. The base station then provides a paging message including its paging-group ID, a corresponding paging cycle, and a corresponding paging offset. The corresponding MSS may thus be switched to the idle-mode. During the idle-mode, the MSS may determine whether to continue or terminate the idle-mode based on the paging message provided by the base station at each paging cycle. II'traffic needs to he Iransmiitcd by the MSS while in the idle-mode, (lie MSS'mny terminate the idle-mode. For example, the MSS may be enabled to terminate the idle-mode by the BS. Furthermore, if the MSS moves to another paging zone or loses its sync while in an idle-mode and is unable to receive a paging at a predefined time, the MSS may terminate the idle-mode. When the MSS is in the idle-mode, the MSS normally receives a periodic paging to secure its free move in the same paging zone without performing the handover procedure. hi configuring a paging zone, a backbone message (paging-group-action), is transferred by wire between base stations. An exemplary paging-group-action backbone message is shown in Table 1. (Table Remove) The paging-group-action backbone message is communicated between base stations. The paging-group-action backbone message may be used for four purposes based on contents of an action field (Action). A receiving base station (target BS) may be assigned (designated) to a specific paging group (Action=0). Alternatively, the target BS may be excluded from the specific paging group (Action=l). Alternatively, the target US may be queried regarding the paging group to which the (argot BS belongs (Action=2). Alternatively, the target BS may be informed of the paging group to which a transmitting base station (sender BS) belongs (Action=3). Since a single base station may belong to one or more paging zones, the paging-group-action backbone message may contain information pertaining to a multitude of paging groups. The base stations may be informed of the paging cycle and offset used in each paging zone via the paging-group-action backbone message. Furthermore, the base stations may be dynamically assigned to the paging groups via the action backbone message. In switching an MSS lo an idle mode, a DREG_REQ message (one of previous MAC messages) is used. A format of the DREG_REQ message is shown in Table 2. (Table Remove) An MSS may send a request to a serving base station that the MSS will be switched to idle mode by setting a De-registration Request Code of the DREG_REQ message to 0x01 and then delivering the DREG_REQ message to the base station. This enables delivery of a specific paging cycle. The serving batse station receives the DREG_REQ message and may respond to the request by the MSS via a conventional OREG CMD message. A formal of (lie DREG CMD message is shown in Table 3. (Table Remove) The serving base station may allow the switching to the idle mode via an action code (Action code = 0x05). Alternatively, the serving base station may allow the MSS to make the request for the switching to the idle mode after a time duration (Action code = 0x06). Alternatively, the serving base station may not allow the MSS to make the request for the switching to the idle mode until the serving base station transmits the DREG CMD message (Action code = 0x07). Details of the action code of the DREG_CMD message are shown in Table 4. (Table Remove) Base stations belonging to the same paging zone may be able to share the information pertaining to the MSS switched to the idle mode. Using this information, the serving BS may notify the MSS of procedures to execute in each paging cycle. A 1'aging-announce backbone message is shown in Table 5. (Table Remove) The paging-announce backbone message may be delivered to all base stations belonging to the same paging zone. The base stations receiving the paging-announce backbone message perform the paging by matching MAC addresses of MSSs included in the message with me paging cycle and offset within the message. Consequently, due to the paging-announce backbone message, all ot" the base stations belonging to a specific paging zone may identically maintain MAC addresses of MSSs to page. Thus, a specific MSS may receive its paging information at each paging cycle unless the MSS leaves (deviates from) a current paging zone. A format of a paging message MOBJ?AG_ADV transmitted to MSSs in the idle mode via paging by each base station is shown in Table 6. The paging message is delivered to MSSs in a broadcast format. (Table Remove) The MSS receives the paging message and may decide whether to maintain the idle mode continuously (Action Code=00), whether to perform ranging to establish a location information update (Action Code=01), and/or whether to terminate the idle mode to receive downlink traffic (Action Code=10). The MSS may terminate the idle mode if the MSS needs to transmit traffic (uplink traffic occurrence). The MSS- also may terminate the idle mode if the MSS needs to receive traffic (downlink t. it'tic occurrence). The MSS also may terminate the idle mode if the MSS is unable to receive a periodic paging due to deviation from a current paging zone or due to a transmission problem. DISCLOSURE OF THE INVENTION The present invention is directed to supporting an idle mode of a mobile station in a wirulcHS nccoss system that substantially obviates one or more problems of the related art. An object of the present invention is to provide supporting an idle mode of a mobile subscriber station (MSS) in a broadband wireless access system, in which actions taken by MSSs in the idle mode to minimize power consumption of the wireless access system are indicated and by which an accurate operation of the idle mode may be secured. Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, in one embodiment, a method of supporting a mobile station that is in an idle mode in a wireless communication system using a paging controller comprises entering an idle mode by a mobile station. The method also comprises receiving a paging command from at least one of the plurality of base stations in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base stations in response to a paging announcement from the paging controller. The method also comprises exiting the idle mode and establishing communication with one of the plurality of base stations, wherein the plurality of base stations in the same paging group receive an idle mode exist status from the paging controller. The paging announcement may preferably be generated from the paging controller when there is downlink traffic data to be delivered to the mobile station. Alternatively, (he paging announcement may preferably be generated from the paging controller when there is uplink traffic data from the mobile station. The idle mode response command may preferably comprise at least one of the paging identifier, a paging cycle and a paging cycle offset. The step of exiting the idle mode and establishing communication may preferably further comprise transmitting a ranging request to one of the plurality of base stations with which the mobile station is associated and receiving a ranging response from the one of the plurality of base stations. The paging announcement may preferably comprise a paging announcement action code comprising at least one of (1) add the mobile station to a paging list; (2) remove the mobile station from the paging list; (3) perform ranging to establish location; and (4) enter network. The paging command action code may preferably comprise at least one of (1) enter network; and (2) perform ranging to establish location. The step of entering the idle mode may preferably further comprise requesting to a serving base station by a mobile station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group. The step of entering the idle mode may also preferably further comprise receiving from the serving base station an idle mode response command to enter the idle mode. The paging controller may preferably be identified with a paging controller identifier and the mobile station is identified with a medium access controller (MAC) identifier. The paging command may preferably comprise information identifying the mobile station by using the MAC identifier. The paging announcement may preferably comprise information identifying the mobile station by using the MAC identifier. The step of entering the idle mode by the mobile station may preferably further comprise the paging controller informing an idle mode entering status of the mobile station to the plurality of base stations in the paging group. In another embodiment, a method of supporting an idle mode by a network in a wireless communication system using a paging controller comprises receiving a request from a mobile station to a serving base station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group. The method also comprises transmitting from the serving base station to the mobile station an idle mode response command to enter the idle mode. The method also comprises transmitting a paging command from at least one of the plurality of base stations in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base stations in response to a paging announcement from the paging controller. The method also comprises establishing communication between one of the plurality of base stations and the mobile station. The method also comprises transmitting an idle mode exist status from the paging controller to the plurality of base stations in the same paging group. The method may also preferably comprise transmitting from the serving base station to the paging controller an idle mode information request message to provide information pertaining to the mobile station. The method may also preferably comprise receiving in the paging controller the idle mode information request message from the serving base station. The met", od may also preferably comprise transmitting from the paging controller to the at ' ;ast one oJ "the plurality of base stations an idle mode information response message if the idle mode information request message comprises information pertaining to a medium access controller (MAC) hash skip threshold. The method may also preferably comprise receiving in the paging controller the idle mode information request message from the serving base station and transmitting from the paging controller to the serving base station an idle mode information response message. The idle mode information response message may also preferably lie transmitted to the nt least one of the plurality of base stations avid may preferably comprise information to notify the at least one of the plurality of base stations that the mobile station has terminated the idle mode. The method may also preferably comprise transmitting from the serving base station to the mobile station an idle mode command message in response to the idle mode information response message. The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. It is to be understood that both the foregoing general description and the following detailed description of the present invention tire exemplary and explanatory and arc intended to provide further explanation of the invention as claimed. IUUEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. FIG, 1 is a block diagram illustrating a paging group, according to an embodiment \ of the present invention. FIG. 2 is a flow diagram illustrating an idle mode procedure, according to an embodiment of the present invention. FIG. 3 is a diagram illustrating a procedure foi terminating an idle mode when downlink traffic is to be transferred to a mobile statioh, according to an embodiment of the present invention. FIG. 4 is a block diagram illustrating a wireless access system having a paging controller, according to an embodiment of the present invention. FIG. 5 is a diagram illustrating a procedure for managing base stations withir a paging group using a paging controller, according to an embodiment of the present invention. FIG. 6 is a diagram illustrating an idle mode initiation procedure in a wireless access system having a paging controller, according to an embodiment of the present invention. FIG. 7 is a flow diagram, illustrating a traffic occurrence in an idle mode mobile station, in a wireless access system having a paging controller, according to an embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION 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. The present invention may be used in the context of the IEEE802 broadband wireless access system standard. Alternatively, the present invention may be used in the context of any type of wireless access system. FIG. 1 is a block diagram illustrating a paging proup, according to an embodiment of the present invention. Referring to FIG. 1, a paging group includes at least one base station (BS). The BS or BSs each belonging to a same paging group may transmit and/or receive information needed for idle mode in a mobile station (MS) via backbone messages. A mobile station is also known as a mobile subscriber station (MSS). Alternatively, information needed for idle mode in an MS may be transmitted and/or received between BSs belonging to different paging groups via backbone messages. FIG. 2 is a flow diagram illustrating an idle mode procedure, according to an embodiment of the present invention. Referring to FIG. 2, to allow an MSS to enter an idle mode, a switching to the idle mode may preferably be requested to a base station using a registration request message, such as for example, a DREG_REQ message as a medium access controller (MAC) mesmige (S2I). An exemplary formnh->f tho DRF.Oi RF.Q message iw shown in Table ?,. The MSS may preferably request to a base station that the MSS enter the idle mode by setting a De-registration Request Code of the DREG_REQ message to 0x01, for example. The MSS may then by'dcliver the DlUi(j_KliQ message lo Ihc base station. The base station that receives the DREG_REQ message (receiving base station) may preferably respond to the request of the MSS via a command message, such as for example, a DREG_CMD message (S22). An exemplary format of the DREG__CMD message is shown in Table 3. The receiving base station may preferably allow the MSS to enter the idle mode via an action code (e.g., Action code = 0x05). Alternatively, the receiving base station may preferably allow the MSS to request entering the idle mode after a specified time duration via another action code (e.g., Action code = 0x06). Alternatively, the receiving base station may not allow the MSS to request entering the idle mode until the receiving base station transmits the DREG_CMD message via another action code (e.g., Action code = 0x07). Exemplary details of action codes pertaining to the DREG_CMD message are shown in Table 4. In one embodiment, base stations belonging to the same paging zone may preferably be able to share information pertaining to MSSs that have entered the idle mode. Using this information, the bases stations may preferably notify the MSSs of what procedures the MSSs need to execute in each paging cycle. In order to share iiiliMMialion among Hie BSs, a backbone message, .such as lor example, a paging- announce backbone message as shown in Table 5 may be used. The paging-announcc backbone message may preferably be delivered to all base stations belonging to fie same paging /.one (S23). In another embodiment, an action code may be added to the paging-announce backbone message for use in instructing MSSs of necessary actions to be performed while in the idle mode. Thus, as in the example of Table 7 below, the 'Num MSS', the 'MSS MAC address', the 'PAGING CYCLE' and, the 'PAGING OFFSET, as well as other fields of the paging-announce backbone message, may be altered as compared to those in Table 5 above. An exemplary paging-announce backbone message with an added action code for instructing the MSSs is shown in Table 7 below. (Table Remove) In yet another embodiment, the 'PAGING_CYCLE (16 bits)' and 'PAG1"NG_OFFSET (8 bits)' fields may be removed from the paging-announce backbone message, as shown in Table 7 above, because each of the base stations belong! tig to the same paging zone possess the same paging cycle and paging offset. Thus, instead of paging cycle and paging offset fields, an action code (e.g., 3-bit action code) may be added to the paging-announce backbone message to indicate that a MAC address associated with a specific MSS has been added to the paging list via an action code (e.g., Action Code=0). Alternatively, the action code may indicate that a MAC address of a specific MSS has been removed from the paging list via another action code (e.g., Action Code=l). Alternatively, the action code may indicate that ranging has been performed for a location information update, (e.g., Action Code=2). Alternatively, the action code may indicate that a re-registration procedure to a network has been executed after terminating the idle mode (e.g., Action Code=3). An exemplary format of a paging message, such as a MOBJPAG_ADV message, tumsmiiiul to the MSSs in Iho idle mode from each of the busc stations via paging is shown in Table 6. The paging message may preferably be transmitted to the MSSs in a broadcast format. The MSS may receive the paging message and determine (decide) whether to maintain the idle mode continuously using an action code (e.g., Action Codc=00), whether to perform ranging to establish a location information update (e.g., Action Code=01), and/or whether to terminate the idle mode to receive downlink traffic (e.g., Action Codc~ 10). A serving base station may preferably allow a specific MSS to enter an idle mode and set an action code of the paging-announce backbone message to 0, for example, and then transmit the paging-announce backbone message to all base stations in the paging zone of the serving base station (S23). Each of the base stations in the paging zone may n'u'iM- flu.; \|M!giitg-iuw(H>nee backbone message ami may sioiu ilie MAC w.l<.s ol ihc corresponding mss in a paging list. the base stations may then transmit mac address via message mob-pag_adv each cycle> The MSS may receive the paging message and may preferably dctcnnine to maintain the idle mode. In so doing, radio resources may be conserved by including the MAC address of the MSS that needs a specific action such as a re-registration to a network or a ranging for a location information update in the paging message. To include the MAC address, the 'MSS MAC Address hash' and 'Action Code' fields of the paging message MOB-PAG_ADV in Table 6 may preferably be changed to match those in Table 8, for example. (Table Remove) If an MSS is forced to terminate the idle mode because of an occurrence of downlink traffic, a respective base station. may be unaware thai llic corresponding MSS belongs to a domain within the paging zone of the respective base station. The respective base station may therefore set the act:">n code of the paging-announce backbone message to 3, for example, and then transfers the paging-announce backbone message to other base stations in the same paging zone. 1 he olhcr base stations in the paging zone of the respective base station may receive the paging-announce backbone message and set the action code of the paging ssage to 00, for example. The other base stations may then transmit the pagng message to all MSSs in the paging zone to enable the corresponding MSS to terminate the idle mode and to execute the procedure for the re-registration to the network. After the MSS has normally terminated its idle mode, the respective base station may set the action code of the paging-announce backbone message to 1, for example, and may then deliver the paging-announce backbone message to the other base stations in the paging zone. Therefore, paging for the corresponding MSS may preferably be stopped. FIG. 3 is a diagram illustrating a procedure for terminating an idle mode when downlink traffic is to be transferred to a mobile station, according to an embodiment of the present invention. Referring to FIG. 3, because a base station may be unaware of the domain to which an MSS in an idle mode belongs, a downlink traffic may preferably be unconditionally delivered to the base station (first base station or initial base station) to which the MSS initially requested a switching to the idle mode. After the MSS allowed to enter the idle mode by the first base station receives f he downlink traffic, the first base station may set an action code, pertaining to all base stations in the paging zone of the first base station, to 11, for example. The first base station may then transmit a paging-announce backbone message (831). Each of the base stations in the paging zone of the first base station may receive the paging-announce message and set an action code of the paging message MOV _PAG_ADV to 10, for example. The base stations may then transmit the paging message to all MSSs in the paging zone in a broadcast format (S32). The corresponding MSS may receive the paging message and terminate the idle mode. The MSS may also request a second base station (current base station) that is in charge of the paging zone to which tK- MSS belongs, for a re-registration to a network (S33). The second base station may preferably b^ made aware of a base station ID of I he first base .station via the paging-announcu message. The second base station may receive the re-registration request and set an action flag of an MSS_Info_Request backbone message to 1, for example. The MSS_lnfo_Request backbone message may preferably be transferred between b ise stations by wire. The second base station may then transmit the MSS_Info_Request backbone message to the first base station to notify the first base station that the MSS has left the paging z.>ne (S34). An exemplary format of the MSS_Info_Request backbone message is shown in Table 9. (Table Remove) The first base station may receive the MSSJtafo_Request backbone message and may notify all base stations within the paging zone of the first base station that the MSS has terminated the idle mode and is to be deleted from paging lists of the respective base stations. The first base station may preferably transmit the traffic of the MSS via a data delivery message having a format shown in Table 10, for example. (Table Remove) Except when the MSS is forced to terminate its idle mode due to downlink traffic, if the idle mode of the MSS needs to be terminated, the MSS may preferably perform an idle mode terminating procedure no later than the first base station requests termination of the idle mode to the MSS via paging. When the base station receives the request of re-registration to the network from the MSS after completion of terminating the idle mode of the MSS, the BS may set the action code of the paging-announce backbone message to 1, for example. The base station may then transfer the paging-announce backbone message to all base stations belonging to the paging zone of the corresponding base station so that the corresponding MSS may be removed from the respective paging lists. FIG. 4 is a block diagram illustrating a wireless access system having a paging controller, according to an embodiment of the present invention. Referring to FIG. 4, a paging controller performs an idle mode control for an MSS in base stations of one or more paging groups by transmitting and/or receiving information necessary for an idle mode support to and/or from the base stations. That is, transmission and/or reception of the information necessary for an idle mode offer may be performed between the base stations via the paging controller. The paging controller may be provided in a specific base station or may be provided separate from the base station. i'iG. 5 is a diagram illustrating u procedure for managing base stations within a paging group using a paging controller, according to an embodiment of the present invention. Referring to FIG. 5, the paging controller may control base stations belonging to each paging group using a backbone message. For example, using an action code of a paging-group action request backbone message, the paging controller may assign a base station to a paging group (e.g., Action Code=0000), remove a base station from a specific paging group (e.g., Action code=0001), request paging information of a corresponding base station (e.g., Action Code^OOlO), or inform paging information of another base station (e.g., Action Code=0011) (S51). An exemplary paging-group-action request message is shown in Table 11. (Table Remove) A base station receiving a paging-group-action request message may preferably transmit information necessary for an idle mode using action codes of a paging-group-action response message. The paging-group-action response message may he transferred to the paging controller by the base station that received the paging-group-action request message (S52). For example, the base station may transmit a response to the paging-group-action request message to add the BS to or remove the BS from the paging group (e.g., Action Code=0000). The paging-group-action response message may also be transmitted in order to offer its paging information (e.g., Action '•i!r 12. (Table Remove) FIG. 6 is a diagram illustuting an idle mode initiation procedure in a wireless access system having a paging controller, according to an embodiment of the present invention. Ueremni', to FIG. 6, when an MSS intends to 'liter an idle mode, the MSS may transmit an idle mode entry request (e.g., DREG-REQ) message to a BS to which the MSS belongs k> request un idle modu entry (S(>l). Tho DKItti KliQ message may include information pertaining to a request for de-registration from the BS to which the MSS belongs (e.g., de-registration request code) and TLV encoded information (e.g., Paging Cycle Request TLV, Idle Mode Retain Information TLV, MAC Hash S1 ip Threshold TLV). 1 lie serving BS may receive the idle mode entry request message and transmit an idle mode information request (e.g., Idle-Info_REQ) message to provide information pertaining to the MSS requesting the idle mode entry to the paging controller (S62). Table 13 shows an exemplary idle mode information request message. (Table Remove) Referring to Table 13, the idle mode information request message may preferably include information that a specific MSS has requested an idle mode entry, a MSS MAC address, MSS service flow information, and TLV encoded information (e.g., Idle Mode Retain InfoniiiUioii II. V.MAC Hash Skip Threshold TLV). The paging controller may receive the idle mode information request message and transmit an idle mode information response (e.g., Idle-Info-RSP) message to the BS that transmitted (lie idle mode information request message (S(>3). II the idle mode information request message transmitted from the serving BS includes information pertaining to the MAC Hash Skip Threshold, the paging controller may preferably transmit the idle mode information response message to all BSs belonging to the paging group (S65). Table 14 shows an exemplary idle mode information response (Idlc-lnfo-RSl1) (Table Remove) Referring to Table 14, the idle mode information response (Idle-Info-RSP) message may preferably include information that the MSS has entered an idle mode, a MSS MAC address, MSS service flow information, and TLV encoded information (e.g., Paging Information TLV, Paging controller ID TLV, Idle Mode Retain Information TLV, MAC Hash Skip Threshold TLV). The BS may receive the idle mode information response (Idle-Info-RSP) message and may transmit an idle mode command (e.g., DREG-CMD) message to the MSS that requested the idle mode entry (S64). The idle mode command message may preferably include information pertaining to commanding the idle mode entry, as well as TLV encoded information (e.g., Paging Information TLV, Paging controller ID TLV, Idle Mode Retain Information TLV, MAC Hash Skip Threshold TLV). FIG. 7 is a flow diagram illustrating a traffic occurrence in an idle mode mob.le station, in a wireless access system having a paging controller, according to an embodiment ol'llic present invention. Referring to FIG.', an MSS may enter an idle mode (S71~S74). The MSS in the idle mode may stay in a BS area where the idle mode entry was performed or may move away into another BS area. An exemplary case in which the MSS in the idle mode moves to a second BS area is described below. If downlink traffic occurs in the idle mode, a first BS to which the MSS belonged when entering the idle mode, may transmit information that downlink traffic has occurred in the idle-mode MSS to a paging controller (S75). The paging controller may transmit a paging-announce message to notify all BSs in the respective paging zone that the idle-mode MSS has terminated the idle mode to re-enter a network (S76, S77). The BSs may then broadcast a paging advertisement message (e.g., MPB-PAG-ADV). An exemplary paging advertisement message is shown in Table 6. Table 15 shows an exemplary paging-announce message. (Table Remove) While in the idle mode, in this example, the MSS has moved to an area of a second BS. The MSS may recognize that downlink traffic is present via a paging advertisement message (e.g., MOB_PAG-ADV) periodically broadcasted to the paging /.one. The MSS may then transmit a ranging request message for network re-entry to the second BS (S78). The second BS may request MSS session information, pertaining to time prior to the idle mode entry, from the paging controller using an idle mode information request message (S79). The paging controller may preferably transmit an idle mode information response message, including MSS session information ard information pertaining to the BS where the MSS was located when entering the idle mode, to the second BS (S80). 1 lie second US may transmit a ranging response message including a handover optiiiu \u« r« fl.tg to the MSS based on the MSS session information and idle mode retain information transmitted from the paging controller (S81). Once the MSS performs a network re-entry procedure (S82), the second BS in charge of the area where the MSS is currently located may notify the paging controller that the MSS has re-entered the network via the idle mode information request message (S83). In so doing, the second BS may include the handover optimization flag (which is included in the ranging response message) in the idle mode information request message. The paging controller may preferably recognize that the MSS has re-entered i.'ie network in a current second BS area after completion of the idle mode entry in the first BS. The paging controller may then command (instruct) that the traffic delivered to the first BS be transmitted to the MSS via the second BS using the idle mode information response message (S84). The first BS may deliver the traffic to the second BS according to the command (instruction) of the pafing controller, The second BS may then transmit the traffic to the MSS (S85). The paging controller may then notify all BSs belonging to the paging group that the MSS has terminated the idle mode, using the idle mode information response message (S86). Each of the BSs may receive the idle mode information response message from the paging controller and remove the MAC address of the MSS from their respective idle mode MSS lists. In one embodiment, if downlink traffic to be transferred to the MSS in the idle mode is transferred via the paging controller, the steps S75 and/or S84 may be omitted. In another embodiment, a method of supporting a mobile station lluil is in ;in idle mode in a wireless communication system using a paging controller comprises entering an idle mode by a mobile station. The method aiso comprises receiving a paging command from at least one of the plurality of base stations in the same paging group, the paging command comprising a paging command action code associated with perfonning ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of b se stations in response to a paging announcement from the paging controller. The method also comprises exiting the idle mode and establishing communication with one of the plurality of base stations, wherein the plurality of base stations in the same paging group receive an idle mode exist status from the paging controller. The paging announcement may preferably be generated from the paging controller when there is downlink traffic data to be delivered to the mobile station. Alternatively, the paging announcement may preferably be generated from the paging controller when there is uplink traffic data from the mobile station. The idle mode response command may preferably comprise at least one of the paging identifier, a paging cycle and a paging cycle offset. The step of exiting the idle mode and establishing communication may preferably further comprise transmitting a ranging request to one of the plurality of base stations with which the mobile station is associated and receiving a ranging response from the one of the plurality of base stations. The paging announcement may preferably comprise a paging announcement action code comprising at least one of (1) add the mobile station to a paging list; (2) remove the mobile station from the paging list; (3) perform ranging to establish location; and (4) enter network. The paging command action code may preferably comprise at least one of (1) enter network; and (2) perform ranging to establish location. The step of entering the idle mode may preferably further comprise requesting to a serving base station by a mobile station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group. The step of entering the idle mode may also preferably further comprise receiving from the serving base station an idle mode response command^to enter the idle mode. The paging controller may preferably be identified with a paging controller identifier and the mobile station is identified with a medium access controller (MAC) identifier. The paging command may preferably comprise information identifying the mobile station by using the MAC identifier. The paging announcement may preferably comprise information identifying the mobile station by using the MAC identifier. The stop of entering the idle mode by the mobile station may preferably further comprise the paging controller informing an idle mode entering status of the mobile station to the plurality of base stations in the paging group. Iii yet another embodiment, a method of supporting an idle mode by a network in a wireless communication system using a paging controller comprises receiving a request from a mobile station to a serving base station to enter an idle mode, wherein (lie serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group. The method also comprises transmitting from the serving base station to the mobile station an idle mode response command to enter the idle mode. The method also comprises transmitting a paging command from at least one of the plurality of base stations in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile .station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base Kialinns in rcspon.sc to a paging announcement from llio puginjj coulrollei. The mulhm! also comprises establishing communication between one of the plurality of base stations and the mobile station. The method also comprises transmitting an idle mode exist status from the paging controller to the plurality of base stations in the same pag' ig group. The method may also preferably comprise transmitting from the serving base station to the paging controller an idle mode information request message to provide information pertaining to the mobile station. The method may also preferably comprise receiving in the paging controller the idle mode information request message from the serving base stution. The method may olao preferably comprise transmitting from the paging controller to the at least one of the plurality of base stations an idle mode information response message if the Hro mode information request message comprises information pertaining to a medium access control ^i (MAC) hash skip threshold. The method may also preferably comprivse receiving in the paging controller the idle mode information request message from the serving base station and transmitting from the paging controller to the serving base station an idle mode information response message. The idle mode information response message may also preferably be transmitted to the at least one of the plurality of base stations and may preferably comprise information to notify the at least one of the plurality of base stations that the mobile station has terminated the idle mode. The method may also preferably comprise transmitting from the serving base station to the mobile station an idle mode command message in response to the idle mode information response message. Accordingly, in the present invention, each base station may include operations of an MSS in the idle moue in u phjjirtjj-announce backbone message. The paging-announce backbone message may be delivered by wire between the base stations via paging. Therefore, the present invention may reduce a size of the paging message (e.g., MOB-PAG ADV) that the MSS delivers to the MSS in the idle mode. Moreover, in a wireless access system having a paging controller, the present invention may efficiently support the idle mode using the paging controller. It will be apparent to :hose skilled in the art that various modifications and variations may be made in the present invention without departing from the spirit or scope of the inventions. Thus, 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. [NDERSTR1AL APPLICABILITY The present invention can be applied to a broadband wireless access system. 1. A method of supporting a mobile -tation that is in an idle mode in a wireless communication system using a paging controller, the method comprising: entering an idle mode by a mobile station; receiving a paging command from ul least one of Iho plurality of ba.w sf.'iltuus in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode fo verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base stations in response to a paging announcement from the paging controller; and exiting the idle mode and establishing communication with one of the plurality of base stations, wherein the plurality of base stations in the same paging group receive an idle mode exist status from the paging controller. —. 2. The method of claim 1, wherein the paging announcement is generated from the paging controller when there is downlink traffic data to be delivered to the mobile station. 3. The method of claim 1, wherein the paging announcement is generated from the paging controller when there is uplink traffic data from the mobile station. 4. The method of claim 1, wherein the idle mode response command comprises at least one ot the paging identifier, a paging cycle and a paging cycle olTsci. 5. The method of claim 1, wherein the step of exiting the idle mode and establishing communication further comprises: transmitting a ranging request to one of the plurality of base stations with which the mobile station is associated; and receiving a ranging response from the one of the plurality of base stations. 6. The method of claim 1, wherein the paging announcement comprises a paging announcement action code comprising at least one of (1) add the mobile station to a paging list; (2) remove the mobile station from the paging list; (3) perform ranging to establish location; and (4) enter network. 7. The method of claim 1, wherein the paging command action code comprises ;il lc;isi OIK: of (I) enter network; and (2) perform runging lo establish 8. The method of claim 1, wherein the step of entering the idle mode further comprises: requesting to a serving base station by a mobile sti'tion to enter un idle mode, wherein the serving base station is associated with u paging controller, the paging controller controlling a plurality of base stations associated with a paging group; and receiving from the serving base station an idle mode response command to enter the idle mode. 9. The method of claim 1, wherein the paging controller is identified with a paging controller identifier and the mobile station is identified with a medium access controller (MAC) identifier. 10. The method of claim 9, wherein the paging command comprises information identifying the mobile station by using the MAC identifier. 1 1 . The method of claim 9, wherein the paging announcement comprises information identifying the mobile station by using the MAC identifier. 12. The method of claim 1, wherein the step of entering the idle mode by the mobile station further comprises the paging controller informing an idle mode entering status of the mobile station to the plurality of base stations in the paging group. 13. A mobile station, comprising: means for entering an idle mode by the mobile station; means for receiving a paging command from at least one of a plurality of base stations in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base stations in response to a paging announcement from a p«f ing controller; and means for exiting the idle mode and establishing communication with one of the plurality of b«w itftttons, wherein the plurality of base stations in the same paging group receive an idle mode exist status from the paging controller. 14, The mobile station of claim 13, wherein the idle mode response command comprises at least one of the paging identifier, a paging cycle and a paging cyolo offset. 15. The mobile station of claim 13, wherein the means for exiting the idle mode and establishing communication further comprises: means for transmitting a ranging request to one of the plurality of base stations will) which the mobile station is associated; and means for receiving a ranging response from the one of the plurality of base stations. 16. The mobile station of claim 13, wherein the paging command action code comprises at least one of (1) enter network; and (2) perform ranging to establish location. 17. The mobile station of claim 13, wherein the means for entering the idle mode further comprises: mean for requesting to « serving base station by a mobile station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group; and means flu receiving front the serving base station an idle nuulo ivspnnsr rommaiul to enter the idle mode. 18 The mobile station of claim 13, wherein the paging controller is identified with a paging controller identifier and the mobile station is identified with a medium access controller (MAC) identifier. 19. The mobile station of claim 13, wherein the means for entering the idle mode by the mobile station further comprises the paging controller informing an idle mode entering status of the mobile station to the plurality of base stations in the paging group. 20. A method of supporting an idle mode by a network in a wireless communication system using a paging controller, the method comprising: receiving a request from a mobile station to a serving base station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group; transmitting from the serving base station to the mobile station an idle mode response command to enter the idle mode; transmitting a paging command from at least one of the plurality of huso slutioiiM in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode *o verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base stations in response to a paging announcement from the paging controller; establishing communication between one of the plurality of base stations and the mobile station; and transmitting an idle mode exist status from the paging controller to the plurality of base stations in the same paging group. 21. The method of claim 20, wherein the paging announcement is generated from the paging controller when there is downlink traffic data to be delivered to the mobile station. 22. The method of claim 20, wherein the paging announcement is generated from the paging controller when there is uplink traffic data from the mobile station. 23. I lie method of claim 20, wherein the idle mode response command comprises at least one of the paging identifier, a paging cycle and a paging cycle offset. 24. The method of claim 20, further comprising: transmitting from the serving base station to the paging controller an idle mode information request message to provide information pertaining to the mobile station. 25. The method of claim 24, further comprising: receiving in the paging controller the idle mode information request message from the serving base station; and transmitting from the paging controller to the at least one of the plurality of base stations an idle mode information response message if the idle mode information request message comprises information pertaining to a medium access controller (MAC) hash skip threshold. 26. The method of claim 24, further comprising: receiving in the paging controller the idle mode information request message from the serving base station; and transmitting from the paging controller to the serving base station an iiilo mode information response message. 27. The method of claim 26, wherein the idle mode information response message is transmitted to the at least one of the plurality of base stations and comprises inhumation to notify the at least one of the plurality of base stations that the mobile station has terminated the idle mode. 2 8. The method of claim 26, further comprising: transmitting from the serving base station to the mobile station an idle mode command message in response to the idle mode information response message. 29. The method of claim 20, wherein the paging announcement comprises a v paging announcement action code comprising at least one of (1) add the mobile station to a paging list; (2) remove the mobile station from the paging list; (3) perform ranging to establish location; and (4) enter network. 30. The method of claim 20, wherein the paging command action code comprises at least one of (1) enter network; and (2) perform ranging to establish 31. The method of claim 20, wherein the paging controller is identified with a paging controller identifier and the mobile station is identified with a medium access controller (MAC) identifier, 32, Abase station configured to support an idle mode by a network in a wireless communication system using a paging controller, the base station comprising: means for receiving a request from a mobile station to a serving base station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group; means for transmitting from the serving base station to the mobile station an idle mode response command to enter the idle mode; tnciins for transmitting a paging command from at least one of the plurality of base stations in the same paging group, the paging commrid comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least OIK- ol'llie plurality of base stations in response to a paging announcement 1'rom llit; paging controller; means for establishing communication between one of the plurality of base-stations and the mobile station; and means for transmitting an idle mode exist status from the paging controller to the plurality oi base stations in the same paging group. 33. The base station of claim 32, wherein the idle mode response command comprises at least one of the paging identifier, a paging cycle and a paging cycle ofl'set. 34. The ba.se station of claim 32, fir'her comprising: means for transmitting from the serving base station to the paging controller an idle mode information request message to provide information pertaining to the mobile station. 35. The base station of claim 34, further comprising: means for receiving in the paging controller the idle mode information request message from the serving base station; and means for transmitting from Ihc paging controller U> the al luisl OIK- of ilu-plurality of base stations an idle mode information response message if the idle mode information request message comprises information pertaining to a medium access controller (MAC) hash skip threshold. 36. The base station of claim 34, further comprising: means for receiving in the paging controller the idle mode information request message from the serving base station; means for transmitting from the paging controller to the serving base station an idle mode information response message. 37. The base station of claim 36, wherein the idle mode information response message is transmitted to the at least one of the plurality of base stations and comprises information to notify the at least one of the plurality of base stations that the mobile station has terminated the idle mode. 3 8. The base station of claim 36, further comprising: means for transmitting from the serving base station to the mobile station an idle mode command message in response to the idle mode information response message. 39. The base station of claim 32, wherein the paging announcement comprise a paging announcement action code comprising at least one of (1) add the mobile station to a paging list; (2) remove the mobile station from the paging list; (3) perform ranging to establish location; and (4) enter network. 40. The base station of claim 32, wherein the paging command action code comprises at least one of (1) enter network; and (2) perform ranging to establish location.

Full Text

SUPPORTING IDLE MODE OF MOBILE STATION
IN WIRELESS ACCESS SYSTEM (Description] TECHNICAL FIELD
The present invention relates generally to a wireless access system and, more particularly, to idle mode of a mobile station in a wireless access system.
BACKGROUND ART
Broadband wireless access systems typically support an idle-mode to minimize the power consumption of a mobile subscriber station (MSS). During the idle-mode, the MSS docs not perform a handover procedure when moving between base stations in the same paging zone. Therefore, the MSS does not need to transmit uplink information for the handover procedure, which'reduces corresponding power consumption.
A paging zone is defined as a zone that is controlled by a plurality of base stations called a paging group. Each of the base stations in the paging group has the same p;i(',in;', i yi'lc (I'ni'.ing Cycle) ami the same paging offset (Paging OHsd).
The MSS may make a request to a base station to switch to the idle-mode. The base station then provides a paging message including its paging-group ID, a corresponding paging cycle, and a corresponding paging offset. The corresponding MSS may thus be switched to the idle-mode. During the idle-mode, the MSS may determine whether to continue or terminate the idle-mode based on the paging message provided by the base station at each paging cycle.

II'traffic needs to he Iransmiitcd by the MSS while in the idle-mode, (lie MSS'mny terminate the idle-mode. For example, the MSS may be enabled to terminate the idle-mode by the BS. Furthermore, if the MSS moves to another paging zone or loses its sync while in an idle-mode and is unable to receive a paging at a predefined time, the MSS may terminate the idle-mode.
When the MSS is in the idle-mode, the MSS normally receives a periodic paging to secure its free move in the same paging zone without performing the handover procedure.
hi configuring a paging zone, a backbone message (paging-group-action), is transferred by wire between base stations. An exemplary paging-group-action backbone message is shown in Table 1. (Table Remove)
The paging-group-action backbone message is communicated between base stations. The paging-group-action backbone message may be used for four purposes based on contents of an action field (Action). A receiving base station (target BS) may be assigned (designated) to a specific paging group (Action=0). Alternatively, the target BS may be excluded from the specific paging group (Action=l). Alternatively, the target US may be queried regarding the paging group to which the (argot BS belongs (Action=2). Alternatively, the target BS may be informed of the paging group to which a transmitting base station (sender BS) belongs (Action=3).
Since a single base station may belong to one or more paging zones, the paging-group-action backbone message may contain information pertaining to a multitude of paging groups. The base stations may be informed of the paging cycle and offset used in each paging zone via the paging-group-action backbone message. Furthermore, the

base stations may be dynamically assigned to the paging groups via the
action backbone message.
In switching an MSS lo an idle mode, a DREG_REQ message (one of previous MAC messages) is used. A format of the DREG_REQ message is shown in Table 2.
(Table Remove)
An MSS may send a request to a serving base station that the MSS will be switched to idle mode by setting a De-registration Request Code of the DREG_REQ message to 0x01 and then delivering the DREG_REQ message to the base station. This enables delivery of a specific paging cycle.
The serving batse station receives the DREG_REQ message and may respond to the request by the MSS via a conventional OREG CMD message. A formal of (lie DREG CMD message is shown in Table 3.
(Table Remove)
The serving base station may allow the switching to the idle mode via an action code (Action code = 0x05). Alternatively, the serving base station may allow the MSS to make the request for the switching to the idle mode after a time duration (Action
code = 0x06). Alternatively, the serving base station may not allow the MSS to make the request for the switching to the idle mode until the serving base station transmits the DREG CMD message (Action code = 0x07).
Details of the action code of the DREG_CMD message are shown in Table 4.
(Table Remove)
Base stations belonging to the same paging zone may be able to share the information pertaining to the MSS switched to the idle mode. Using this information, the serving BS may notify the MSS of procedures to execute in each paging cycle.
A 1'aging-announce backbone message is shown in Table 5.
(Table Remove)

The paging-announce backbone message may be delivered to all base stations belonging to the same paging zone. The base stations receiving the paging-announce backbone message perform the paging by matching MAC addresses of MSSs included in the message with me paging cycle and offset within the message.
Consequently, due to the paging-announce backbone message, all ot" the base
stations belonging to a specific paging zone may identically maintain MAC addresses of MSSs to page. Thus, a specific MSS may receive its paging information at each paging cycle unless the MSS leaves (deviates from) a current paging zone.
A format of a paging message MOBJ?AG_ADV transmitted to MSSs in the idle mode via paging by each base station is shown in Table 6. The paging message is delivered to MSSs in a broadcast format. (Table Remove)
The MSS receives the paging message and may decide whether to maintain the idle mode continuously (Action Code=00), whether to perform ranging to establish a location information update (Action Code=01), and/or whether to terminate the idle mode to receive downlink traffic (Action Code=10).
The MSS may terminate the idle mode if the MSS needs to transmit traffic (uplink traffic occurrence). The MSS- also may terminate the idle mode if the MSS needs to receive traffic (downlink t. it'tic occurrence). The MSS also may terminate the idle mode if the MSS is unable to receive a periodic paging due to deviation from a current paging zone or due to a transmission problem.
DISCLOSURE OF THE INVENTION
The present invention is directed to supporting an idle mode of a mobile station in a wirulcHS nccoss system that substantially obviates one or more problems of the related art.
An object of the present invention is to provide supporting an idle mode of a mobile subscriber station (MSS) in a broadband wireless access system, in which actions taken by MSSs in the idle mode to minimize power consumption of the wireless access system are indicated and by which an accurate operation of the idle mode may be secured.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, in one embodiment, a method of supporting a mobile station that is in an idle mode in a wireless communication system using a paging controller comprises entering an idle mode by a mobile station. The method also comprises receiving a paging command from at least one of the plurality of base stations in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base stations in response to a paging announcement from the paging controller. The method also comprises exiting the idle mode and establishing communication with one of the plurality of base stations, wherein the plurality of base stations in the same paging group receive an idle mode exist status from the paging controller.
The paging announcement may preferably be generated from the paging controller when there is downlink traffic data to be delivered to the mobile station. Alternatively,
(he paging announcement may preferably be generated from the paging controller when there is uplink traffic data from the mobile station. The idle mode response command may preferably comprise at least one of the paging identifier, a paging cycle and a paging cycle offset. The step of exiting the idle mode and establishing communication may preferably further comprise transmitting a ranging request to one of the plurality of base stations with which the mobile station is associated and receiving a ranging response from the one of the plurality of base stations.
The paging announcement may preferably comprise a paging announcement action code comprising at least one of (1) add the mobile station to a paging list; (2) remove the mobile station from the paging list; (3) perform ranging to establish location; and (4) enter network. The paging command action code may preferably comprise at least one of (1) enter network; and (2) perform ranging to establish location.
The step of entering the idle mode may preferably further comprise requesting to a serving base station by a mobile station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group. The step of entering the idle mode may also preferably further comprise receiving from the serving base station an idle mode response command to enter the idle mode.
The paging controller may preferably be identified with a paging controller identifier and the mobile station is identified with a medium access controller (MAC) identifier. The paging command may preferably comprise information identifying the mobile station by using the MAC identifier. The paging announcement may preferably
comprise information identifying the mobile station by using the MAC identifier. The step of entering the idle mode by the mobile station may preferably further comprise the paging controller informing an idle mode entering status of the mobile station to the plurality of base stations in the paging group.
In another embodiment, a method of supporting an idle mode by a network in a wireless communication system using a paging controller comprises receiving a request from a mobile station to a serving base station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group. The method also comprises transmitting from the serving base station to the mobile station an idle mode response command to enter the idle mode. The method also comprises transmitting a paging command from at least one of the plurality of base stations in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base stations in response to a paging announcement from the paging controller. The method also comprises establishing communication between one of the plurality of base stations and the mobile station. The method also comprises transmitting an idle mode exist status from the paging controller to the plurality of base stations in the same paging group.
The method may also preferably comprise transmitting from the serving base
station to the paging controller an idle mode information request message to provide information pertaining to the mobile station. The method may also preferably comprise receiving in the paging controller the idle mode information request message from the serving base station. The met", od may also preferably comprise transmitting from the paging controller to the at ' ;ast one oJ "the plurality of base stations an idle mode information response message if the idle mode information request message comprises information pertaining to a medium access controller (MAC) hash skip threshold.
The method may also preferably comprise receiving in the paging controller the idle mode information request message from the serving base station and transmitting from the paging controller to the serving base station an idle mode information response message. The idle mode information response message may also preferably lie transmitted to the nt least one of the plurality of base stations avid may preferably comprise information to notify the at least one of the plurality of base stations that the mobile station has terminated the idle mode. The method may also preferably comprise transmitting from the serving base station to the mobile station an idle mode command message in response to the idle mode information response message.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings. It is to be understood that both the foregoing general description and the following detailed description of the present invention tire exemplary and explanatory and arc intended to provide further explanation of the invention as claimed.
IUUEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
FIG, 1 is a block diagram illustrating a paging group, according to an embodiment \ of the present invention.
FIG. 2 is a flow diagram illustrating an idle mode procedure, according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a procedure foi terminating an idle mode when downlink traffic is to be transferred to a mobile statioh, according to an embodiment of the present invention.
FIG. 4 is a block diagram illustrating a wireless access system having a paging controller, according to an embodiment of the present invention.
FIG. 5 is a diagram illustrating a procedure for managing base stations withir a paging group using a paging controller, according to an embodiment of the present invention.
FIG. 6 is a diagram illustrating an idle mode initiation procedure in a wireless access system having a paging controller, according to an embodiment of the present invention.
FIG. 7 is a flow diagram, illustrating a traffic occurrence in an idle mode mobile station, in a wireless access system having a paging controller, according to an embodiment of the present invention.
BEST MODE FOR CARRYING OUT THE INVENTION
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.
The present invention may be used in the context of the IEEE802 broadband wireless access system standard. Alternatively, the present invention may be used in the context of any type of wireless access system.
FIG. 1 is a block diagram illustrating a paging proup, according to an embodiment of the present invention.
Referring to FIG. 1, a paging group includes at least one base station (BS). The BS or BSs each belonging to a same paging group may transmit and/or receive information needed for idle mode in a mobile station (MS) via backbone messages. A mobile station is also known as a mobile subscriber station (MSS). Alternatively, information needed for idle mode in an MS may be transmitted and/or received between BSs belonging to different paging groups via backbone messages.
FIG. 2 is a flow diagram illustrating an idle mode procedure, according to an embodiment of the present invention.
Referring to FIG. 2, to allow an MSS to enter an idle mode, a switching to the idle mode may preferably be requested to a base station using a registration request message, such as for example, a DREG_REQ message as a medium access controller (MAC) mesmige (S2I). An exemplary formnh->f tho DRF.Oi RF.Q message iw shown in Table ?,.
The MSS may preferably request to a base station that the MSS enter the idle mode by setting a De-registration Request Code of the DREG_REQ message to 0x01, for example. The MSS may then by'dcliver the DlUi(j_KliQ message lo Ihc base station.
The base station that receives the DREG_REQ message (receiving base station) may preferably respond to the request of the MSS via a command message, such as for example, a DREG_CMD message (S22). An exemplary format of the DREG__CMD message is shown in Table 3.
The receiving base station may preferably allow the MSS to enter the idle mode via an action code (e.g., Action code = 0x05). Alternatively, the receiving base station may preferably allow the MSS to request entering the idle mode after a specified time duration via another action code (e.g., Action code = 0x06). Alternatively, the receiving base station may not allow the MSS to request entering the idle mode until the receiving base station transmits the DREG_CMD message via another action code (e.g., Action code = 0x07).
Exemplary details of action codes pertaining to the DREG_CMD message are shown in Table 4.
In one embodiment, base stations belonging to the same paging zone may preferably be able to share information pertaining to MSSs that have entered the idle mode. Using this information, the bases stations may preferably notify the MSSs of what procedures the MSSs need to execute in each paging cycle. In order to share iiiliMMialion among Hie BSs, a backbone message, .such as lor example, a paging-
announce backbone message as shown in Table 5 may be used. The paging-announcc backbone message may preferably be delivered to all base stations belonging to fie same paging /.one (S23).
In another embodiment, an action code may be added to the paging-announce backbone message for use in instructing MSSs of necessary actions to be performed while in the idle mode. Thus, as in the example of Table 7 below, the 'Num MSS', the 'MSS MAC address', the 'PAGING CYCLE' and, the 'PAGING OFFSET, as well as other fields of the paging-announce backbone message, may be altered as compared to those in Table 5 above. An exemplary paging-announce backbone message with an added action code for instructing the MSSs is shown in Table 7 below. (Table Remove)
In yet another embodiment, the 'PAGING_CYCLE (16 bits)' and 'PAG1"NG_OFFSET (8 bits)' fields may be removed from the paging-announce backbone message, as shown in Table 7 above, because each of the base stations belong! tig to the same paging zone possess the same paging cycle and paging offset. Thus, instead of paging cycle and paging offset fields, an action code (e.g., 3-bit action code) may be added to the paging-announce backbone message to indicate that a MAC address associated with a specific MSS has been added to the paging list via an action code (e.g., Action Code=0). Alternatively, the action code may indicate that a MAC address of a specific MSS has been removed from the paging list via another action code (e.g., Action Code=l). Alternatively, the action code may indicate that ranging has been performed for a location information update, (e.g., Action Code=2). Alternatively, the action code may indicate that a re-registration procedure to a network has been executed after terminating the idle mode (e.g., Action Code=3).
An exemplary format of a paging message, such as a MOBJPAG_ADV message, tumsmiiiul to the MSSs in Iho idle mode from each of the busc stations via paging is
shown in Table 6. The paging message may preferably be transmitted to the MSSs in a broadcast format.
The MSS may receive the paging message and determine (decide) whether to maintain the idle mode continuously using an action code (e.g., Action Codc=00), whether to perform ranging to establish a location information update (e.g., Action Code=01), and/or whether to terminate the idle mode to receive downlink traffic (e.g., Action Codc~ 10).
A serving base station may preferably allow a specific MSS to enter an idle mode and set an action code of the paging-announce backbone message to 0, for example, and then transmit the paging-announce backbone message to all base stations in the paging zone of the serving base station (S23). Each of the base stations in the paging zone may n'u'iM- flu.; |M!giitg-iuw(H>nee backbone message ami may sioiu ilie MAC w.l<.s ol ihc corresponding mss in a paging list. the base stations may then transmit mac address via message mob-pag_adv each cycle> The MSS may receive the paging message and may preferably dctcnnine to maintain the idle mode. In so doing, radio resources may be conserved by including the MAC address of the MSS that needs a specific action such as a re-registration to a network or a ranging for a location information update in the paging message. To include the MAC address, the 'MSS MAC Address hash' and 'Action Code' fields of the paging message MOB-PAG_ADV in Table 6 may preferably be changed to match those in Table 8, for example. (Table Remove)
If an MSS is forced to terminate the idle mode because of an occurrence of downlink traffic, a respective base station. may be unaware thai llic corresponding MSS belongs to a domain within the paging zone of the respective base station. The respective base station may therefore set the act:">n code of the paging-announce backbone message to 3, for example, and then transfers the paging-announce backbone message to other base stations in the same paging zone.
1 he olhcr base stations in the paging zone of the respective base station may receive the paging-announce backbone message and set the action code of the paging ssage to 00, for example. The other base stations may then transmit the pagng
message to all MSSs in the paging zone to enable the corresponding MSS to terminate the idle mode and to execute the procedure for the re-registration to the network.
After the MSS has normally terminated its idle mode, the respective base station may set the action code of the paging-announce backbone message to 1, for example, and may then deliver the paging-announce backbone message to the other base stations in the paging zone. Therefore, paging for the corresponding MSS may preferably be stopped.
FIG. 3 is a diagram illustrating a procedure for terminating an idle mode when downlink traffic is to be transferred to a mobile station, according to an embodiment of the present invention.
Referring to FIG. 3, because a base station may be unaware of the domain to which an MSS in an idle mode belongs, a downlink traffic may preferably be unconditionally delivered to the base station (first base station or initial base station) to which the MSS initially requested a switching to the idle mode.
After the MSS allowed to enter the idle mode by the first base station receives f he downlink traffic, the first base station may set an action code, pertaining to all base stations in the paging zone of the first base station, to 11, for example. The first base station may then transmit a paging-announce backbone message (831).
Each of the base stations in the paging zone of the first base station may receive the paging-announce message and set an action code of the paging message MOV _PAG_ADV to 10, for example. The base stations may then transmit the paging message to all MSSs in the paging zone in a broadcast format (S32).
The corresponding MSS may receive the paging message and terminate the idle mode. The MSS may also request a second base station (current base station) that is in
charge of the paging zone to which tK- MSS belongs, for a re-registration to a network (S33). The second base station may preferably b^ made aware of a base station ID of I he first base .station via the paging-announcu message.
The second base station may receive the re-registration request and set an action flag of an MSS_Info_Request backbone message to 1, for example. The MSS_lnfo_Request backbone message may preferably be transferred between b ise stations by wire. The second base station may then transmit the MSS_Info_Request backbone message to the first base station to notify the first base station that the MSS has left the paging z.>ne (S34). An exemplary format of the MSS_Info_Request
backbone message is shown in Table 9. (Table Remove)
The first base station may receive the MSSJtafo_Request backbone message and may notify all base stations within the paging zone of the first base station that the MSS has terminated the idle mode and is to be deleted from paging lists of the respective
base stations.
The first base station may preferably transmit the traffic of the MSS via a data delivery message having a format shown in Table 10, for example. (Table Remove)

Except when the MSS is forced to terminate its idle mode due to downlink traffic, if the idle mode of the MSS needs to be terminated, the MSS may preferably perform an idle mode terminating procedure no later than the first base station requests termination of the idle mode to the MSS via paging.
When the base station receives the request of re-registration to the network from the MSS after completion of terminating the idle mode of the MSS, the BS may set the action code of the paging-announce backbone message to 1, for example. The base station may then transfer the paging-announce backbone message to all base stations belonging to the paging zone of the corresponding base station so that the corresponding MSS may be removed from the respective paging lists.
FIG. 4 is a block diagram illustrating a wireless access system having a paging controller, according to an embodiment of the present invention.
Referring to FIG. 4, a paging controller performs an idle mode control for an MSS in base stations of one or more paging groups by transmitting and/or receiving information necessary for an idle mode support to and/or from the base stations. That is, transmission and/or reception of the information necessary for an idle mode offer may be performed between the base stations via the paging controller. The paging controller

may be provided in a specific base station or may be provided separate from the base
station.
i'iG. 5 is a diagram illustrating u procedure for managing base stations within a paging group using a paging controller, according to an embodiment of the present
invention.
Referring to FIG. 5, the paging controller may control base stations belonging to each paging group using a backbone message. For example, using an action code of a paging-group action request backbone message, the paging controller may assign a base station to a paging group (e.g., Action Code=0000), remove a base station from a specific paging group (e.g., Action code=0001), request paging information of a corresponding base station (e.g., Action Code^OOlO), or inform paging information of another base station (e.g., Action Code=0011) (S51). An exemplary paging-group-action request message is shown in Table 11. (Table Remove)
A base station receiving a paging-group-action request message may preferably transmit information necessary for an idle mode using action codes of a paging-group-action response message. The paging-group-action response message may he transferred to the paging controller by the base station that received the paging-group-action request message (S52). For example, the base station may transmit a response to the paging-group-action request message to add the BS to or remove the BS from the paging group (e.g., Action Code=0000). The paging-group-action response message may also be transmitted in order to offer its paging information (e.g., Action '•i!r 12. (Table Remove)
FIG. 6 is a diagram illustuting an idle mode initiation procedure in a wireless access system having a paging controller, according to an embodiment of the present
invention.

Ueremni', to FIG. 6, when an MSS intends to 'liter an idle mode, the MSS may transmit an idle mode entry request (e.g., DREG-REQ) message to a BS to which the MSS belongs k> request un idle modu entry (S(>l). Tho DKItti KliQ message may include information pertaining to a request for de-registration from the BS to which the MSS belongs (e.g., de-registration request code) and TLV encoded information (e.g., Paging Cycle Request TLV, Idle Mode Retain Information TLV, MAC Hash S1 ip Threshold TLV).
1 lie serving BS may receive the idle mode entry request message and transmit an idle mode information request (e.g., Idle-Info_REQ) message to provide information pertaining to the MSS requesting the idle mode entry to the paging controller (S62). Table 13 shows an exemplary idle mode information request message. (Table Remove) Referring to Table 13, the idle mode information request message may preferably include information that a specific MSS has requested an idle mode entry, a MSS MAC address, MSS service flow information, and TLV encoded information (e.g., Idle Mode Retain InfoniiiUioii II. V.MAC Hash Skip Threshold TLV).
The paging controller may receive the idle mode information request message and transmit an idle mode information response (e.g., Idle-Info-RSP) message to the BS that transmitted (lie idle mode information request message (S(>3). II the idle mode information request message transmitted from the serving BS includes information pertaining to the MAC Hash Skip Threshold, the paging controller may preferably transmit the idle mode information response message to all BSs belonging to the paging group (S65).
Table 14 shows an exemplary idle mode information response (Idlc-lnfo-RSl1) (Table Remove)
Referring to Table 14, the idle mode information response (Idle-Info-RSP) message may preferably include information that the MSS has entered an idle mode, a MSS MAC address, MSS service flow information, and TLV encoded information (e.g., Paging Information TLV, Paging controller ID TLV, Idle Mode Retain Information TLV, MAC Hash Skip Threshold TLV).
The BS may receive the idle mode information response (Idle-Info-RSP) message and may transmit an idle mode command (e.g., DREG-CMD) message to the MSS that requested the idle mode entry (S64). The idle mode command message may preferably include information pertaining to commanding the idle mode entry, as well as TLV encoded information (e.g., Paging Information TLV, Paging controller ID TLV, Idle Mode Retain Information TLV, MAC Hash Skip Threshold TLV).
FIG. 7 is a flow diagram illustrating a traffic occurrence in an idle mode mob.le
station, in a wireless access system having a paging controller, according to an embodiment ol'llic present invention.
Referring to FIG.', an MSS may enter an idle mode (S71~S74). The MSS in the idle mode may stay in a BS area where the idle mode entry was performed or may move away into another BS area. An exemplary case in which the MSS in the idle mode moves to a second BS area is described below.
If downlink traffic occurs in the idle mode, a first BS to which the MSS belonged when entering the idle mode, may transmit information that downlink traffic has occurred in the idle-mode MSS to a paging controller (S75). The paging controller may transmit a paging-announce message to notify all BSs in the respective paging zone that the idle-mode MSS has terminated the idle mode to re-enter a network (S76, S77). The BSs may then broadcast a paging advertisement message (e.g., MPB-PAG-ADV). An exemplary paging advertisement message is shown in Table 6.
Table 15 shows an exemplary paging-announce message. (Table Remove)
While in the idle mode, in this example, the MSS has moved to an area of a second BS. The MSS may recognize that downlink traffic is present via a paging advertisement message (e.g., MOB_PAG-ADV) periodically broadcasted to the paging /.one. The MSS may then transmit a ranging request message for network re-entry to the second BS (S78). The second BS may request MSS session information, pertaining to time prior to the idle mode entry, from the paging controller using an idle mode information request message (S79). The paging controller may preferably transmit an idle mode information response message, including MSS session information ard
information pertaining to the BS where the MSS was located when entering the idle mode, to the second BS (S80).
1 lie second US may transmit a ranging response message including a handover optiiiu \*u« r« fl.tg to the MSS based on the MSS session information and idle mode retain information transmitted from the paging controller (S81). Once the MSS performs a network re-entry procedure (S82), the second BS in charge of the area where the MSS is currently located may notify the paging controller that the MSS has re-entered the network via the idle mode information request message (S83). In so doing, the second BS may include the handover optimization flag (which is included in the ranging response message) in the idle mode information request message.
The paging controller may preferably recognize that the MSS has re-entered i.'ie network in a current second BS area after completion of the idle mode entry in the first BS. The paging controller may then command (instruct) that the traffic delivered to the first BS be transmitted to the MSS via the second BS using the idle mode information response message (S84).
The first BS may deliver the traffic to the second BS according to the command (instruction) of the pafing controller, The second BS may then transmit the traffic to the MSS (S85). The paging controller may then notify all BSs belonging to the paging group that the MSS has terminated the idle mode, using the idle mode information response message (S86). Each of the BSs may receive the idle mode information response message from the paging controller and remove the MAC address of the MSS from their respective idle mode MSS lists.
In one embodiment, if downlink traffic to be transferred to the MSS in the idle mode is transferred via the paging controller, the steps S75 and/or S84 may be omitted.
In another embodiment, a method of supporting a mobile station lluil is in ;in idle mode in a wireless communication system using a paging controller comprises entering an idle mode by a mobile station. The method aiso comprises receiving a paging command from at least one of the plurality of base stations in the same paging group, the paging command comprising a paging command action code associated with perfonning ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of b se stations in response to a paging announcement from the paging controller. The method also comprises exiting the idle mode and establishing communication with one of the plurality of base stations, wherein the plurality of base stations in the same paging group receive an idle mode exist status from the paging controller.
The paging announcement may preferably be generated from the paging controller when there is downlink traffic data to be delivered to the mobile station. Alternatively, the paging announcement may preferably be generated from the paging controller when there is uplink traffic data from the mobile station. The idle mode response command may preferably comprise at least one of the paging identifier, a paging cycle and a paging cycle offset. The step of exiting the idle mode and establishing communication may preferably further comprise transmitting a ranging request to one of the plurality of
base stations with which the mobile station is associated and receiving a ranging response from the one of the plurality of base stations.
The paging announcement may preferably comprise a paging announcement action code comprising at least one of (1) add the mobile station to a paging list; (2) remove the mobile station from the paging list; (3) perform ranging to establish location; and (4) enter network. The paging command action code may preferably comprise at least one of (1) enter network; and (2) perform ranging to establish location.
The step of entering the idle mode may preferably further comprise requesting to a serving base station by a mobile station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group. The step of entering the idle mode may also preferably further comprise receiving from the serving base station an idle mode response command^to enter the idle mode.
The paging controller may preferably be identified with a paging controller identifier and the mobile station is identified with a medium access controller (MAC) identifier. The paging command may preferably comprise information identifying the mobile station by using the MAC identifier. The paging announcement may preferably comprise information identifying the mobile station by using the MAC identifier. The stop of entering the idle mode by the mobile station may preferably further comprise the paging controller informing an idle mode entering status of the mobile station to the plurality of base stations in the paging group.
Iii yet another embodiment, a method of supporting an idle mode by a network in a wireless communication system using a paging controller comprises receiving a request from a mobile station to a serving base station to enter an idle mode, wherein (lie serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group. The method also comprises transmitting from the serving base station to the mobile station an idle mode response command to enter the idle mode. The method also comprises transmitting a paging command from at least one of the plurality of base stations in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile .station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base Kialinns in rcspon.sc to a paging announcement from llio puginjj coulrollei. The mulhm! also comprises establishing communication between one of the plurality of base stations and the mobile station. The method also comprises transmitting an idle mode exist status from the paging controller to the plurality of base stations in the same pag' ig group.
The method may also preferably comprise transmitting from the serving base station to the paging controller an idle mode information request message to provide information pertaining to the mobile station. The method may also preferably comprise receiving in the paging controller the idle mode information request message from the serving base stution. The method may olao preferably comprise transmitting from the
paging controller to the at least one of the plurality of base stations an idle mode information response message if the Hro mode information request message comprises information pertaining to a medium access control ^i (MAC) hash skip threshold.
The method may also preferably comprivse receiving in the paging controller the idle mode information request message from the serving base station and transmitting from the paging controller to the serving base station an idle mode information response message. The idle mode information response message may also preferably be transmitted to the at least one of the plurality of base stations and may preferably comprise information to notify the at least one of the plurality of base stations that the mobile station has terminated the idle mode. The method may also preferably comprise transmitting from the serving base station to the mobile station an idle mode command message in response to the idle mode information response message.
Accordingly, in the present invention, each base station may include operations of an MSS in the idle moue in u phjjirtjj-announce backbone message. The paging-announce backbone message may be delivered by wire between the base stations via paging. Therefore, the present invention may reduce a size of the paging message (e.g., MOB-PAG ADV) that the MSS delivers to the MSS in the idle mode. Moreover, in a wireless access system having a paging controller, the present invention may efficiently support the idle mode using the paging controller.
It will be apparent to :hose skilled in the art that various modifications and variations may be made in the present invention without departing from the spirit or scope of the inventions. Thus, 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.
[NDERSTR1AL APPLICABILITY
The present invention can be applied to a broadband wireless access system.

1. A method of supporting a mobile -tation that is in an idle mode in a wireless communication system using a paging controller, the method comprising:
entering an idle mode by a mobile station;
receiving a paging command from ul least one of Iho plurality of ba.w sf.'iltuus in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode fo verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base stations in response to a paging announcement from the paging controller; and
exiting the idle mode and establishing communication with one of the plurality of base stations, wherein the plurality of base stations in the same paging group receive an idle mode exist status from the paging controller.
—.
2. The method of claim 1, wherein the paging announcement is generated from the paging controller when there is downlink traffic data to be delivered to the mobile station.

3. The method of claim 1, wherein the paging announcement is generated from
the paging controller when there is uplink traffic data from the mobile station.
4. The method of claim 1, wherein the idle mode response command comprises
at least one ot the paging identifier, a paging cycle and a paging cycle olTsci.
5. The method of claim 1, wherein the step of exiting the idle mode and establishing communication further comprises:
transmitting a ranging request to one of the plurality of base stations with which the mobile station is associated; and
receiving a ranging response from the one of the plurality of base stations.
6. The method of claim 1, wherein the paging announcement comprises a paging announcement action code comprising at least one of (1) add the mobile station to a paging list; (2) remove the mobile station from the paging list; (3) perform ranging to establish location; and (4) enter network.
7. The method of claim 1, wherein the paging command action code comprises

;il lc;isi OIK: of (I) enter network; and (2) perform runging lo establish
8. The method of claim 1, wherein the step of entering the idle mode further comprises:
requesting to a serving base station by a mobile sti'tion to enter un idle mode, wherein the serving base station is associated with u paging controller, the paging controller controlling a plurality of base stations associated with a paging group; and receiving from the serving base station an idle mode response command to enter the idle mode.
9. The method of claim 1, wherein the paging controller is identified with a
paging controller identifier and the mobile station is identified with a medium access
controller (MAC) identifier.
10. The method of claim 9, wherein the paging command comprises information
identifying the mobile station by using the MAC identifier.
1 1 . The method of claim 9, wherein the paging announcement comprises information identifying the mobile station by using the MAC identifier.

12. The method of claim 1, wherein the step of entering the idle mode by the mobile station further comprises the paging controller informing an idle mode entering status of the mobile station to the plurality of base stations in the paging group.
13. A mobile station, comprising:
means for entering an idle mode by the mobile station;
means for receiving a paging command from at least one of a plurality of base stations in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base stations in response to a paging announcement from a
p«f ing controller; and
means for exiting the idle mode and establishing communication with one of the plurality of b«w itftttons, wherein the plurality of base stations in the same paging group receive an idle mode exist status from the paging controller.
14, The mobile station of claim 13, wherein the idle mode response command

comprises at least one of the paging identifier, a paging cycle and a paging cyolo offset.
15. The mobile station of claim 13, wherein the means for exiting the idle mode and establishing communication further comprises:
means for transmitting a ranging request to one of the plurality of base stations will) which the mobile station is associated; and
means for receiving a ranging response from the one of the plurality of base stations.
16. The mobile station of claim 13, wherein the paging command action code comprises at least one of (1) enter network; and (2) perform ranging to establish location.
17. The mobile station of claim 13, wherein the means for entering the idle mode further comprises:
mean* for requesting to « serving base station by a mobile station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group; and

means flu receiving front the serving base station an idle nuulo ivspnnsr rommaiul to enter the idle mode.
18 The mobile station of claim 13, wherein the paging controller is identified with a paging controller identifier and the mobile station is identified with a medium access controller (MAC) identifier.
19. The mobile station of claim 13, wherein the means for entering the idle mode by the mobile station further comprises the paging controller informing an idle mode entering status of the mobile station to the plurality of base stations in the paging
group.
20. A method of supporting an idle mode by a network in a wireless communication system using a paging controller, the method comprising:
receiving a request from a mobile station to a serving base station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group;
transmitting from the serving base station to the mobile station an idle mode response command to enter the idle mode;

transmitting a paging command from at least one of the plurality of huso slutioiiM in the same paging group, the paging command comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode *o verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least one of the plurality of base stations in response to a paging announcement from the paging controller;
establishing communication between one of the plurality of base stations and the mobile station; and
transmitting an idle mode exist status from the paging controller to the plurality of base stations in the same paging group.
21. The method of claim 20, wherein the paging announcement is generated
from the paging controller when there is downlink traffic data to be delivered to the
mobile station.
22. The method of claim 20, wherein the paging announcement is generated
from the paging controller when there is uplink traffic data from the mobile station.

23. I lie method of claim 20, wherein the idle mode response command comprises at least one of the paging identifier, a paging cycle and a paging cycle offset.
24. The method of claim 20, further comprising:
transmitting from the serving base station to the paging controller an idle mode information request message to provide information pertaining to the mobile
station.
25. The method of claim 24, further comprising:
receiving in the paging controller the idle mode information request message from the serving base station; and
transmitting from the paging controller to the at least one of the plurality of base stations an idle mode information response message if the idle mode information request message comprises information pertaining to a medium access controller (MAC) hash skip threshold.
26. The method of claim 24, further comprising:
receiving in the paging controller the idle mode information request message from the serving base station; and

transmitting from the paging controller to the serving base station an iiilo mode information response message.
27. The method of claim 26, wherein the idle mode information response message is transmitted to the at least one of the plurality of base stations and comprises inhumation to notify the at least one of the plurality of base stations that the mobile station has terminated the idle mode.
2 8. The method of claim 26, further comprising:
transmitting from the serving base station to the mobile station an idle mode command message in response to the idle mode information response message.
29. The method of claim 20, wherein the paging announcement comprises a v
paging announcement action code comprising at least one of (1) add the mobile station
to a paging list; (2) remove the mobile station from the paging list; (3) perform ranging to establish location; and (4) enter network.
30. The method of claim 20, wherein the paging command action code
comprises at least one of (1) enter network; and (2) perform ranging to establish

31. The method of claim 20, wherein the paging controller is identified with a paging controller identifier and the mobile station is identified with a medium access controller (MAC) identifier,
32, Abase station configured to support an idle mode by a network in a wireless communication system using a paging controller, the base station comprising:
means for receiving a request from a mobile station to a serving base station to enter an idle mode, wherein the serving base station is associated with a paging controller, the paging controller controlling a plurality of base stations associated with a paging group;
means for transmitting from the serving base station to the mobile station an idle mode response command to enter the idle mode;
tnciins for transmitting a paging command from at least one of the plurality of base stations in the same paging group, the paging commrid comprising a paging command action code associated with performing ranging while the mobile station is in the idle mode to verify availability of the mobile station with respect to at least one of the base stations in the paging group, wherein the paging command is generated from the at least

OIK- ol'llie plurality of base stations in response to a paging announcement 1'rom llit; paging controller;
means for establishing communication between one of the plurality of base-stations and the mobile station; and
means for transmitting an idle mode exist status from the paging controller to the plurality oi base stations in the same paging group.
33. The base station of claim 32, wherein the idle mode response command comprises at least one of the paging identifier, a paging cycle and a paging cycle ofl'set.
34. The ba.se station of claim 32, fir'her comprising:
means for transmitting from the serving base station to the paging controller an idle mode information request message to provide information pertaining to the mobile station.
35. The base station of claim 34, further comprising:
means for receiving in the paging controller the idle mode information request message from the serving base station; and

means for transmitting from Ihc paging controller U> the al luisl OIK- of ilu-plurality of base stations an idle mode information response message if the idle mode information request message comprises information pertaining to a medium access controller (MAC) hash skip threshold.
36. The base station of claim 34, further comprising: means for receiving in the paging controller the idle mode information request
message from the serving base station;
means for transmitting from the paging controller to the serving base station an
idle mode information response message.
37. The base station of claim 36, wherein the idle mode information response message is transmitted to the at least one of the plurality of base stations and comprises information to notify the at least one of the plurality of base stations that the mobile station has terminated the idle mode.
3 8. The base station of claim 36, further comprising:
means for transmitting from the serving base station to the mobile station an idle mode command message in response to the idle mode information response message.

39. The base station of claim 32, wherein the paging announcement comprise a
paging announcement action code comprising at least one of (1) add the mobile station
to a paging list; (2) remove the mobile station from the paging list; (3) perform ranging
to establish location; and (4) enter network.
40. The base station of claim 32, wherein the paging command action code
comprises at least one of (1) enter network; and (2) perform ranging to establish
location.

Documents:

155-delnp-2007-Abstract-(15-04-2014).pdf

155-delnp-2007-abstract.pdf

155-delnp-2007-assignment.pdf

155-delnp-2007-Claims-(15-04-2014).pdf

155-delnp-2007-claims.pdf

155-delnp-2007-Correspondence Others-(15-04-2014).pdf

155-delnp-2007-correspondence-others.pdf

155-delnp-2007-Description (Complete)-(15-04-2014).pdf

155-delnp-2007-description (complete).pdf

155-delnp-2007-drawings.pdf

155-delnp-2007-form-1.pdf

155-delnp-2007-Form-2-(15-04-2014).pdf

155-delnp-2007-form-2.pdf

155-delnp-2007-Form-3-(15-04-2014).pdf

155-delnp-2007-form-3.pdf

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Patent Number

265363

Indian Patent Application Number

155/DELNP/2007

PG Journal Number

08/2015

Publication Date

20-Feb-2015

Grant Date

20-Feb-2015

Date of Filing

05-Jan-2007

Name of Patentee

LG ELECTRONICS INC.

Applicant Address

20, YOIDO-DONG, YOUNGDUNGPO-GU, SEOUL, 150-721 (KR)

Inventors:

#	Inventor's Name	Inventor's Address
1	RYU, GI SEON	19-4, JUNGGYEBON-DONG, NOWON-GU, SEOUL 139-229 (KR)
2	KWAK, YONG WON	503-1005, EUNHASOO APT., BISAN-DONG, DONGAN-GU, ANYANG-SI, GYEONGGI-DO 431-050 (KR)
3	KIM, BEOM JOON	76-16, SAMSEONG-DONG, GANGNAM-GU, SEOUL 135-090 (KR)
4	KIM, YONG HO	1503-1304, HANIREUM-HYUN DAI APT., SANGDONG, WONMI-GU, BUCHEON-SI, GYEONGGI-DO 420-816 (KR)

PCT International Classification Number

H04Q7/38; H04Q7/38

PCT International Application Number

PCT/KR2005/001699

PCT International Filing date

2005-06-07

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10-2005-0013912	2005-02-19	Republic of Korea
2	10-2005-0019258	2005-03-08	Republic of Korea
3	10-2004-0041539	2004-06-07	Republic of Korea