4.4 MHz = 22 ARFCN
What you could do with that is BBH with at most 6 TRX per BTS (for instance 2/2/2). But this is a really complicated network design… To be on the safe side, you should limit your at 4 or 5 TRX per BTS max.
With such small frequency band, you can’t do more ! So in order to ease your work, you should use AMR Half-Rate in order to double your capacity.
So the way I see it:
in rural areas : tri-sectors 1/1/1 for wide coverage or omni cells with 3 or 4 TRX’s for village coverage.
in urban areas: tri-sectors 2/2/1 with half rate and BBH.
in dense areas, that’s a problem. 1) You have the efficient but expensive solution of few umbrella cells (bi-sectors, 1/1, electrical tilt) and lots of microcells.
2) You have the cheap, quick, but time-limited, solution of putting only 2/2/1 or sometimes 2/2/2 with strong electrical downtilt and low height.. Best would be wall mounted, to avoid backlobes.
But after a while, if you have many subscribers, you will lack capacity. Howvere you can’t add TRX because your frequency planning is already so tight !
Therefore you’ll have to remove 1 or 2 “umbrellas TRX” and add many microcells. Or add a new frequency band (for instance DCS1800), or a new radio access network such as UMTS.
Ok, good luck 🙂