08.313GPPLocation Services (LCS): Serving Mobile Location Centre - Serving Mobile Location Centre (SMLC - SMLC)SMLCPP specificationTS
4.1 RIT Procedures
Two modes of operation are supported:
– provision of RIT information on request. In this mode a SMLC Client needing RIT information requests it from another SMLC using the RIT Query operation. The SMLC Server sends the requested RIT information using the RIT Indication operation. There are two cases:
– single indication: RIT Indication is requested only once.
In this case the procedure consists of one RIT Query and one RIT Indication operations.
– Open-ended repetitive RIT Indications: RIT information is requested on a regular basis until the RIT Query Stop operation.
In this case the procedure consists of one RIT Query, one or more RIT Indication, and one RIT Query Stop operations.
– Autonomous provision of RIT information. In this mode, the RIT information is provided automatically by the SMLC Server, according to an internal configuration not managed through SMLCPP (e.g., by O&M).
In the autonomous mode the procedure consists of one or more RIT Indication operations.
Three RIT related operations are then included in the SMLCPP, one for requesting the provision of RIT data, the second for provision, and the third one for stopping open-ended repetitive indications.
4.1.1 RIT Query Operation
This operation allows a SMLC to query RIT information from another SMLC. This operation consists of sending of a RIT Query Request. It includes the Request ID , that is used to identify different queries. The RIT Query Request also includes the description of the scheduling of RIT Indication operations in the reverse direction. This includes the following cases:
– single indication; RIT Indication is requested only once;
– open-ended repetitive indications; RIT Indication operations are requested on a regular basis until the RIT Query Stop operation.
A RIT Query Response includes the same Request ID that the Request included, and it is used as a positive acknowledgement. A RIT Query Error message can be sent in return, if the SMLC Server detects an error situation (e.g. syntax errors, or overlapping Request ID values), or it can not fullfil the Request (e.g. RIT information is requested for unknown BTSs ). It contains the same Request ID values as the Request.
4.1.2 RIT Indication Operation
This operation allows a SMLC to send RIT information to another SMLC. It can be used both in the cased of autonomous provision, and the provision of RIT information on request.
The RIT Indication Request contains RIT information to be delivered. It also contains the Request ID that:
– has the same value as the RIT Query operation, that invoked the RIT Indication (RIT provision on request);
– has a reserved value indicating autonomous provision.
A RIT Indication Response includes the same Request ID that the Request included, and it is used as a positive acknowledgement. The SMLC Client can send a RIT Indication Error to the SMLC Server, if it detects an error situation (e.g. syntax errors, or unknown Request ID values).
4.1.3 RIT Query Stop Operation
This operation allows a SMLC to send an indication to another SMLCPP to stop sending RIT information, that it has originally asked to obtain on open-ended repetitive basis. The RIT Query Stop Request includes the Request ID values that is the same as in the corresponding RIT Query that should be stopped. A RIT Query Stop Response includes the same Request ID that the Request included, and it is used as a positive acknowledgement. The SMLC Server can send a RIT Query Stop Error to the SMLC Client, if it detects an error situation (e.g. syntax errors, or unknown Request ID values).
4.2 TOA Procedure
This procedure includes a single operation, for requesting and obtaining TOA measurements for a single MS, and performed by one or several LMUs, as determined by the SMLC Server.
4.2.1 Perform TOA Measurement Operation
The Perform TOA Measurement Request message includes all the relevant details pertaining to the MS from which to measure signals. The Response message includes the results from one or several LMUs. An error message is returned by the SMLC Server in the case the request cannot be fulfilled (e.g. the LMUs can not measure the MS), or there is another error situation (syntax errors). The Request ID value in the Response, and the possible Error are the same as in the Request.
4.3 Deciphering Keys Procedure
This procedure includes one operation that is related to LCS assistance data broadcast deciphering keys. With this operation the SMLC Server controlling the deciphering keys (needed in LCS Assistance Data broadcast) can send the deciphering keys to other SMLC Clients in the same location area. One SMLC (i.e. SMLC Server) in location area is selected to control the deciphering keys and sending the keys to other SMLC Clients in location area. The sending has to be done to each SMLC Client with a separate message.
4.3.1 Deciphering Keys Update Operation
This operation allows a SMLC controlling deciphering keys to send the keys to another SMLC Client.
The Deciphering Keys Update Request includes the Request ID and information of keys. A Deciphering Keys Update Response includes only the same Request ID that the Request included, and it is used as a positive acknowledgement. The SMLC Client can send a Deciphering Keys Update Error to the SMLC Server, if it detects an error situation (e.g. syntax errors). It contains the same Request ID values as the Request.