- This topic has 3 replies, 1 voice, and was last updated 12 years, 7 months ago by pix.
11th September 2008 at 04:40 #53856engineerGuest
Can somebody suggest how can i re use my freq spectrum of 4.4 Mhz……also can i use frequency hopping in that.11th September 2008 at 07:55 #53857pixGuest
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 🙂
Pix18th September 2008 at 14:14 #53858EmmanuelGuest
I have a suggestion:
With this already 22 channels, i suggest you employ RF Frequency Hopping, with the following split…
BCCH – 15 Channels
Guard Band – 1 Channel
TCH(MA List) – 6 Hopping Channels (1X1 hopping on the MA List)
The bottle neck is there is that as the network grows,you will have to trade off between voice quality and capacity.18th September 2008 at 17:38 #53859pixGuest
1 hopping trx / cell and only 6 frequencies is very very very risky. you can be sure that you’ll get high call drops and poor voice quality.