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Hi all!
Have you any idea about why after setting ACT parameter to ADJ (BTS parameter, defining which frequencies should be measured in Active mode by MS, ADJ means that BCCHs of Adjacent cells will be measured) we got 4 times more Intra-cell HOs and 2 times more HOs, degraded Rxqual, high TCH drops, but 1-2% better inter-cell HO success?
Network is with SYN hopping, Intra-cell HO is enabled, Intra-cell HO interference is enabled, priority for TCH allocation – BCCH TRX (TRP=1), Idle mode BAL consists of All BCCHs in the BCCH band used in the city. SIngle band network with 900, frequency reuse pattern is very tight due to narrow allowed band (13 BCCHs and 12 TCH channels).
Previously ACT was equal to IDLE.Yes, and another point is that INTER cell HO has higher priority than INTRA cell.
Anyway if we consider Active mode operation before and after the change we have the following:
Before: MS measured All 13 BCCHs in Active mode (the same as in Idle). Only measurements for serving cells and 6 the best candidates are reported to BSC. But among these 6 reported BCCH/BSIC combinations there may be cells which ARE NOT DEFINED as Adjacencies. So HO attempts can be initated to less cells.
After: MS measures only BCCHs of Adjacent cells. This means that to any of BCCH/BSIC combinations HO attempt is possible. -> we have more HO attempts for INTER-CELL HO, because BSC is aware of more candidates and more correct decision will be taken. -> HO success increase is expected.
This is logical.
But what is the relation to Rxqual degradation – thus more Intra-cell HO are performed and more TCH drops are detected.
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