Content for TR 22.952 Word version: 17.0.0
This clause illustrates a MO Priority Service call establishment with early assignment for a Service User. In this scenario, radio traffic channels are not available when the Priority Service call is attempted, the queue for the cell is full, but the Service User's Priority Service priority is greater than one or more Priority Service requests already in the queue.
As no idle radio traffic channel is available on receipt of the Assignment Request, the queue for the cell is full, and the Service User's Priority Service priority is greater than one or more of the Priority Service requests already in the queue, then the lowest priority, most recent request in the queue is removed from the queue. The new Assignment Request message is placed in the queue in accordance with the Service User's priority and call request arrival time at the cell.
The BSS returns a Queuing Indication message to the MSC/VLR for the request that was just queued (User 1 in Figure 5.9) and starts BSSMAP timer T11. The required steps that follow are the same as described in steps I-R of Clause 5.3 if an idle radio traffic channel is available before the BSSMAP timer T11 expires or in steps I-P of Clause 5.7 if the BSSMAP timer T11 expires before an idle radio traffic channel becomes available.
The BSS initiates the clearing procedure, stops timer T11, and returns an Assignment Failure message to the MSC/VLR with cause "No Radio Resource Available"
for the request that was removed from the queue (User 2 in Figure 5.9
). The required steps that follow are the same as described in steps I-N of Clause 5.5