The BBH : The number of hopping frequency is equal to the number of TRX
the more TRX you have, better it is to avoid interference
BBH coud be handle by RTC combiner. This combiner could combine 6 DRX with 3dB insertion loss. BS_TxPower_max with RTC is greater than BS_TXPowerMax with Hybrid combiner (SFH case).
I’ve got good results with BBH with Nokia
If you have only 2 DRX pe rsector, it’s not enough to avoid interference (go to SFH).
SFH : The number of hopping frequency depends to the MAL, MAIO.
if you have 2 TRX by sector, you could hope with all frequency contained on the MAL to avoid interference.
Only Hybrid combiner could handle SFH. This kind of combiner, combine only 4 DRX with 3 dB of insertion loss. If you set more DRX your insertion loss shift from 3 to 6 dB. Decrease of BS_TX_Power_max. maybe, it doesn’t matter in urban dense area.
I hope I could help anyone.