thank you very much for your explanations.
I’ve changed to BBH in one of urban areas 11 BTS in DCS 1800. The rest are GSM900 which are still in SFH. I noticed that there are improvements in quality, especially UL for 1800 MHz. I’m not sure if it will succeed with the rest of 15 BTS in GSM900. Another question, is BBH better in terms of penetration indoor in DCS1800?