TEMS VISUALIZATION SUMMARY VIEW FAQS

1. Why is the total number of dropped calls reported by TEMS Visualization usually less than the total reported by the STS recording?

2. Why is the total TCH Drop Call count in the TRU List sometimes lower than the total TCH Drop Call count from the Recorded cell List?

3. Why is the sum of Incoming HO Failure different in the Recorded Cell List from the TRU list?

ANSWERS

1. Why is the total number of dropped calls reported by TEMS Visualization usually less than the total reported by the STS recording?
TEMS Visualization does not include calls that started prior to the recording period. These calls are counted in the total reported by the STS recording.

2. Why is the total TCH Drop Call count in the TRU List sometimes lower than the total TCH Drop Call count from the Recorded cell List?

The dropped call message (CS Call Release) only contains information on the serving cell at the time of the drop. It does not give any information about the serving channel. So we must get this information on the channel from the latest Channel Busy message and then carry this forward until the call ends in a drop.

This is the reason why the number of dropped calls in the TX and RX lists can sometimes be slightly less than the number of dropped calls in the cell list.

We confirm which is the serving channel at the time the call is dropped by looking for the last Channel Busy message which is followed by Handover Complete or Assignment Complete (i.e. we know that that channel was successfully assigned).

If we do not have a previous Channel Busy followed by Handover Complete or Assignment Complete then we cannot say what the serving channel was - and so we cannot assign the dropped call to a particular channel or TX/RX.

This can happen when for example the call was started before the start of the log-file and then the call is dropped. We don't know what the serving channel is because we miss a Channel Busy message followed by Handover Complete or Assignment Complete.

3. Why is the sum of Incoming HO Failure different in the Recorded Cell List from the TRU list?

Starting with TV 4.0, incoming handover statistics for Cell Information data and TRU data are kept in a consistent manner by the new state engine thus should be similar. The reason for any difference between the counts can be traced to one of the following reasons:

It is always known which cell the call dropped on from the Clear Command message - but the channel and TRU the call dropped must be carried over from the latest, Assignment/Handover Command, Channel Busy, Assignment/Handover Complete message sequence. This could be missing for example for a call that starts before the start of the log file or for a call that performs a handover into the recording area (where complete data for a TRU has not been accumulated due to the missing Handover Command or Assignment Command).

Take care to differentiate Handover and Incoming Handover statistics. The former is tagged for serving cells, while the latter is tagged for the target.