8.31 Location Related Data

25.4133GPPRelease 17TSUTRAN Iu interface Radio Access Network Application Part (RANAP) signalling

8.31.1 General

The purpose of the Location Related Data procedure is to provide the means to handle additional location-related requests over the Iu interface: it allows the CN to either retrieve from the RNC deciphering keys (to be forwarded to the UE) for the broadcast assistance data, or request the RNC to deliver dedicated assistance data to the UE. The procedure uses connection oriented signalling.

8.31.2 Successful Operation

Figure 37: Location Related Data procedure. Successful operation.

The CN initiates the procedure by generating a LOCATION RELATED DATA REQUEST message to the RNC.

Upon reception of the LOCATION RELATED DATA REQUEST message, the RNC shall initiate the requested function indicated in the Location Related Data Request Type IE.

The Location Related Data Request Type IE indicates to the RNC whether:

– to start dedicated assistance data delivery to the UE, or

– to send deciphering keys for broadcast assistance data to the CN.

If the LOCATION RELATED DATA REQUEST message included a request for dedicated assistance data delivery to the UE, and if the dedicated assistance data was successfully delivered to the UE, the RNC shall respond to the CN with a LOCATION RELATED DATA RESPONSE message containing no data.

If the LOCATION RELATED DATA REQUEST message included a request for deciphering keys of broadcast assistance data, the RNC shall respond to the CN with a LOCATION RELATED DATA RESPONSE message containing the Broadcast Assistance Data Deciphering Keys IE.

8.31.2.1 Successful Operation for GERAN Iu mode

Upon reception of the LOCATION RELATED DATA REQUEST message, the BSS shall initiate the requested function indicated in the Location Related Data Request Type IE or the Location Related Data Request Type Specific To GERAN Iu Mode IE.

In the sole case of a request for GERAN Iu mode specific positioning method, E-OTD, defined in TS 43.059 [29], the LOCATION RELATED DATA REQUEST message shall include the Location Related Data Request Type Specific To GERAN Iu Mode IE and not the Location Related Data Request Type IE.

The Location Related Data Request Type IE or the Location Related Data Request Type Specific To GERAN Iu Mode IE shall indicate to the BSS whether:

– to start dedicated assistance data delivery to the UE, or

– to send deciphering keys for broadcast assistance data to the CN.

8.31.3 Unsuccessful Operation

Figure 38: Location Related Data procedure. Unsuccessful operation.

If the RNC was not able to successfully deliver the requested dedicated assistance data to the UE, or if the RNC is not able to provide the requested deciphering keys, the RNC shall send a LOCATION RELATED DATA FAILURE message including the Cause IE to the CN. The Cause IE shall indicate the appropriate cause value to the CN, e.g. "Dedicated Assistance data Not Available" or "Deciphering Keys Not Available".

8.31.4 Abnormal Conditions

8.31.4.1 Abnormal Conditions for GERAN Iu mode

If the Location Related Data Request Type IE and Location Related Data Request Type Specific To GERAN Iu Mode IE are both included in the LOCATION RELATED DATA REQUEST message, the BSS shall reject the procedure by sending a LOCATION RELATED DATA FAILURE message.

If the Location Related Data Request Type IE is set to the value "Deciphering Keys for UE Based OTDOA" or "Dedicated Assistance Data for UE Based OTDOA", the BSS shall reject the procedure by sending a LOCATION RELATED DATA FAILURE message.