Verifying availability of idle-mode mobile subscriber station in wireless access system

Abstract

A method of verifying availability of a mobile subscriber station that is in an idle-mode includes requesting to a base station by the mobile subscriber station to enter an idle-mode, wherein the base station is associated with a paging group comprising a plurality of base stations, and receiving from the base station an idle-mode response command to enter the idle-mode. The method also includes receiving from the base station a paging command comprising an action code associated with performing ranging while the mobile subscriber station is in the idle-mode to verify availability of the mobile subscriber station with respect to the base station, wherein if the ranging is not successfully performed with the base station during a predetermined period, the base station continues to transmit the paging command until a paging retrial count reaches a predetermined threshold.

What is claimed is: 
     
         1 . A method for controlling a power down by a base station (B S), the method comprising:
 receiving, from a Mobile Station (MS), a ranging request message indicating a power down of the MS;   performing a location update of the MS as part of the power down of the MS;   releasing idle-mode information related to the MS if the location update due to the power down of the MS is successful; and   transmitting a ranging response message to indicate the release of the idle-mode information related to the MS,   wherein the MS is in idle mode, the MS having entered the idle mode by performing de-registration in a paging zone.   
     
     
         2 . The method of  claim 1 , further comprising determining unavailability of the MS and deleting the idle-mode information if the MS fails to answer for a location update polling up to a paging retry count. 
     
     
         3 . The method of  claim 1 , further comprising performing an availability check of the MS using location update polling if the power down location update of the MSS is unsuccessful. 
     
     
         4 . The method of  claim 1 , further comprising stopping idle-mode paging control for the MS at the time of power down. 
     
     
         5 . The method of  claim 1 , further comprising:
 receiving, from MS in the paging zone, a de-registration request (DREG-REQ) message, the DREG-REQ message being transmitted to enter the idle-mode; and   transmitting, to the MS, a de-registration response command (DREG-CMD) in response to the DREG-REQ message, the DREG-CMD comprising paging information related to at least one of a paging grouping identification, a paging cycle, and a paging offset.   
     
     
         6 . The method of  claim 5 , wherein the MS in the idle-mode moves from a coverage of the BS to a coverage of another BS without a handover procedure. 
     
     
         7 . The method of  claim 1 , wherein the BS transmits the paging message to the MS according to a paging cycle. 
     
     
         8 . A method for controlling a power down by a mobile station (MS), the method comprising:
 transmitting a ranging request message to indicate a power down of the MS; and   receiving, from a base station (B S), a ranging response message indicating a release of idle-mode information related to the MS if a location update due to the power down of the MS is successful,   wherein the MS is in idle mode, the MS having entered the idle mode by performing de-registration in a paging zone, and   wherein the paging control for the MS in idle-mode is stopped at the time of the power down.   
     
     
         9 . The method of  claim 8 , further comprising:
 transmitting, in the paging zone, a de-registration request (DREG-REQ) message, the DREG-REQ message being transmitted to enter the idle-mode; and   receiving, from the BS, a de-registration response command (DREG-CMD) in response to the DREG-REQ message, the DREG-CMD comprising paging information related to at least one of a paging grouping identification, a paging cycle, and a paging offset.   
     
     
         10 . The method of  claim 9 , wherein the MS in the idle-mode moves from a coverage of the BS to a coverage of another BS without a handover procedure. 
     
     
         11 . The method of  claim 8 , wherein the BS transmits the paging message to the MS according to a paging cycle. 
     
     
         12 . A base station (BS) for controlling a power down, the BS comprising:
 a receiver to receive, from a Mobile Station (MS), a ranging request message indicating a power down of the MS.   a processor to perform a location update of the MS as part of the power down of the MS, and to release idle-mode information related to the MS if a location update due to the power down of the MS is successful; and   a transmitter to transmit a ranging response message to indicate the release of the idle-mode information related to the MS,   wherein the MS is in idle mode, the MS having entered the idle mode by performing de-registration in a paging zone.