When an MS requires network services for reasons such as the Mobile Originated Call (MOC), Mobile Terminated Call (MTC), emergency call, call re-establishment, location updating, packet call, and Location Measurement Unit (LMU)+Reserved, it sends the BTS a CHAN REQ message on the RACH. After receiving this message, the BTS reports a CHAN RQD message to the BSC for a signaling channel.
After receiving the CHAN RQD message, the BSC assigns and activates a signaling channel to the MS. If the BSC receives a CHAN ACTIV ACK message from the BTS, the signaling channel is ready for the assignment. The BSC sends an IMM ASS CMD message, requesting the MS to access the specified signaling channel. This signaling channel can be an SDCCH or a TCH.
After receiving a FIRST SABM frame from the MS, the BTS sends an EST IND message to the BSC.
After receiving the EST IND message that carries an MM message (CM SERV REQ message, LOC UPD REQ message, IMSI DTCH message, PAG RSP message, CM RE-EST REQ message, SS ACTIVATION message, LCS message), the BSC requests the MSC to establish the A interface connection and transparently transmits the MM message to the MSC.
Figure 1 shows the immediate assignment measurement procedure.
Cell.
The following table lists the measurement counters related to Immediate Assignment Measurement per Cell.
Counter |
Refer to Section... |
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