Measurement Counter
M3221a:CELL_CALL_DROPS_BTSLOOP_FAIL_BTS_FAIL_TCHH
Description
After the call is put through or the incoming BSC handover for the speech service is complete, the call processing module initiating loopback start at one end sends a loopback request message to the call processing module at the peer end within the BSC during the BTS local loopback start. The call processing module at the peer end sends a BTS loopback request message to the BTS. The BTS speech loopback in the cell at the peer end fails because of various reasons. The BTS returns a BTS loopback acknowledgement message to the call processing module with the cause value of BTS loopback failure. Then, the call processing module at the peer end responds to the call processing module at the end initiating loopback start with a loopback acknowledgement message with the cause value of failures on the BTS side. The BSC regards it as a call drop and releases the call directly.
This measurement provides the number of call drops on TCHH due to BTS loopback start failure (failures on the BTS side).
Unit
Integer number or integer.
Measurement Point
After the BSC receives the CONNECT ACK message from the MSC in the MS terminated call procedure, as shown in Figure 1 (A1), or after the BSC receives the HANDOVER CMP message from the MS in the incoming BSC handover procedure for the speech service, as shown in Figure 2 (B1), the BSC selects the BSS local switch policy, determines the local switch start conditions, and performs local switch call detection. If all the local switch conditions are met, the BTS local loopback start procedure is started. Within the BSC, the call processing module initiating loopback start at one end sends a loopback request message to the call processing module at the peer end. The call processing module at the peer end sends a BTS loopback request message to the BTS. The BTS speech loopback in the cell at the peer end fails because of various reasons. The BTS returns a BTS loopback acknowledgement message to the call processing module with the cause value of loopback failure on the BTS side. Then, the call processing module at the peer end responds to the call processing module at the end initiating loopback start with a loopback acknowledgement message with the cause value of failures on the BTS side. The BSC regards it as a call drop and releases the call directly. If the channel that carries the call during the call drop is a TCHH, this counter is measured.
Formula
This is an original counter without involving any formula.