The purpose of the procedures that are grouped together in this clause is to enable Endpoint A to request assistance data from Endpoint B to assist in positioning, and to enable Endpoint B to transfer assistance data to Endpoint A in the absence of a request.
The Assistance Data Transfer procedure is shown in
Figure 5.2.2-1.
Step 1.
Endpoint A sends a RequestAssistanceData message to Endpoint B.
Step 2.
Endpoint B responds with a ProvideAssistanceData message to Endpoint A containing assistance data. The transferred assistance data should match or be a subset of the assistance data requested in step 1. Endpoint B may also provide any not requested information that it considers useful to Endpoint A. If step 3 does not occur, this message shall set the endTransaction IE to TRUE.
Step 3.
Endpoint B may transmit one or more additional ProvideAssistanceData messages to Endpoint A containing further assistance data. The transferred assistance data should match or be a subset of the assistance data requested in step 1. Endpoint B may also provide any not requested information that it considers useful to Endpoint A. The last message shall include the endTransaction IE set to TRUE.
The Assistance Data Delivery procedure allows Endpoint B to provide unsolicited assistance data to Endpoint A and is shown in
Figure 5.2.3-1.
Step 1.
Endpoint B sends a ProvideAssistanceData message to Endpoint A containing assistance data. If step 2 does not occur, this message shall set the endTransaction IE to TRUE.
Step 2.
Endpoint B may transmit one or more additional ProvideAssistanceData messages to Endpoint A containing additional assistance data. The last message shall include the endTransaction IE set to TRUE.
When triggered to transmit a
RequestAssistanceData message, Endpoint A shall:
1 >
set the method specific RequestAssistanceData IEs in accordance with the information received from upper layers.
1 >
deliver the message to lower layers for transmission.
Upon receiving a
RequestAssistanceData message, Endpoint B shall generate a
ProvideAssistanceData message as a response.
Endpoint B shall:
1 >
for each positioning method for which a request for assistance data is included in the message:
2 >
if Endpoint B supports this positioning method:
3 >
include the assistance data for that supported positioning method in the response message;
1 >
set the SessionID IE in the response message to the same value as the SessionID IE in the received message if received;
1 >
set the SLPP-TransactionID IE in the response message to the same value as the SLPP-TransactionID IE in the received message;
1 >
deliver the response message to lower layers for transmission.
Upon receiving a
ProvideAssistanceData message, Endpoint A shall:
1 >
for each positioning method contained in the message:
2 >
deliver the related assistance data to upper layers.