Question: What action should the Serving Radio Network Controller (SRNC) take upon receiving a PHYSICAL CHANNEL RECONFIGURATION REQUEST while an Unsynchronised Radio Link Reconfiguration procedure is ongoing?
Option 1: Process the request and send a PHYSICAL CHANNEL RECONFIGURATION COMMAND to the UE.
Option 2: Send a PHYSICAL CHANNEL RECONFIGURATION FAILURE message to the DRNC immediately.
Option 3: Wait for the completion of the ongoing Unsynchronised Radio Link Reconfiguration procedure before responding.
Option 4: Ignore the request, assuming the DRNC has terminated the Physical Channel Reconfiguration procedure due to another overriding message.
Explanation: According to the specified behavior in abnormal conditions for RNSAP signalling, if an SRNC receives a PHYSICAL CHANNEL RECONFIGURATION REQUEST while another radio link procedure (like Unsynchronised Radio Link Reconfiguration) is ongoing, it should ignore the request. This is because the presence of these other messages implies that the DRNC has likely aborted the Physical Channel Reconfiguration procedure, thus the SRNC should not respond with a failure message, maintaining protocol integrity and avoiding unnecessary signalling traffic in the UTRAN interface.