7.3 State Description for the BSC

03.713GPPFunctional descriptionLocation Services (LCS)Release 1999Stage 2TS

7.3.1 BSC States

7.3.1.1 IDLE State

In this state, the BSC location service is inactive for a particular MS.

7.3.1.2 LOCATION State

In this state, the BSC is awaiting a response from a BSS based SMLC or the VMSC after requesting the location for a particular MS. In this state, a Radio Resource connection to the target MS will be active – allowing the SMLC and MS to exchange positioning related messages for mobile based and mobile assisted position methods. For certain position methods (e.g. network based position methods), the SMLC may invoke substates in the BSC during which other types of association or procedure are supported with the MS (e.g. temporary call establishment, handover). Such substates are defined in later sections for each positioning method. In this state, the BSC may transfer positioning related messages between the SMLC and the target MS and/or between the SMLC and certain LMUs served by the BSC.

7.3.2 State Functionality

7.3.2.1 State Transitions

Figure 23: State Transitions in the BSC

Moving from IDLE to LOCATION state:

After a request has been received (e.g. from the VMSC or from a client internal to the BSC) to locate a particular MS served by the BSC, a location request is sent to either the BSS based SMLC associated with the serving cell or to the VMSC (with an NSS based SMLC): the BSC then enters the LOCATION state. Before entering this state, a Radio Resource connection to the MS must have been already established by the VMSC.

Moving from LOCATION to IDLE state:

After the return of a location estimate result from the SMLC or VMSC, the BSC shall reenter IDLE state.

7.3.2.2 LOCATION Timer Function

The BSC runs a timer while in the LOCATION state to limit the amount of time waiting for a location response from the SMLC or VMSC. If the timer expires before such information is received, the BSC indicates a location failure to the original requesting entity and reenters IDLE state.