11 : TCH measurements observations
The maximum number of cells observed for this measurement type is 1 cell.
Basically, it gives you access to all info pre-processed by the BSC (averages of rxlev, rxqual, ta, ms tx pwr, PBGT, RXLEV from neighbours, PBGT from neighbours, etc.)
26 : TCH outgoing handover per adjacency measurements
Up to 40 serving cells can be selected per BSC
It counts the outgoing HO requests, failures, etc, per adjacency and per type of HO (EMERGENCY, BETTER CELL, TRAFFIC, …)
27 : 2G TCH incoming handover per adjacency
Only one target cell can be selected per BSS
Same as 26, but for incoming HO (all details…)
Do you need more information ?
Regards,