7.4 State Description for the SMLC

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

7.4.1 SMLC States

7.4.1.1 NULL State

This is a conceptual rather than actual state in which a certain location request from a particular VMSC or BSC either has not yet been received or has been completed.

7.4.1.2 LOCATION State

This state exists after the SMLC has received a location request from a VMSC or BSC and persists while the SMLC is obtaining position measurements for a particular positioning method until such time as positioning measurements have been received and a location estimate has been computed and returned to the VMSC or BSC.

When sufficient positioning measurement results have been received, the SMLC either evaluates them, if they include an already computed location estimate, or uses them to compute a location estimate. The SMLC then has the option of either reinitiating another positioning attempt, e.g. if the location estimate did not satisfy the required QoS and the requirement on response time permits another position attempt, or returning the location estimate to the VMSC or BSC.

7.4.2 State Functionality

7.4.2.1 State Transitions

Figure 24: State Transitions in the SMLC

Moving from NULL to LOCATION state:

After a location request is received from the VMSC or BSC, the SMLC enters the LOCATION state. It then chooses a positioning method and initiates the appropriate position measurements.

Moving from LOCATION to NULL state:

When the SMLC has obtained a location estimate that best meets the requested QoS parameters, it returns this to the VMSC or BSC and reenters the NULL state.

7.4.2.2 LOCATION Timer Function

The SMLC runs a timer while in the LOCATION state to limit the total amount of time that positioning can be active. This timer should be related to any response time indicated in the location request QoS parameters. If the timer expires before a final location estimate has been produced, the SMLC either returns the best existing location estimate to the VMSC (e.g. an estimate based on the current cell ID) or returns a failure indication. It then reenters the NULL state.