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Frequency Planning

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  • #53856
    engineer
    Guest

    Can somebody suggest how can i re use my freq spectrum of 4.4 Mhz……also can i use frequency hopping in that.

    #53857
    pix
    Guest

    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 🙂
    Regards,
    Pix

    #53858
    Emmanuel
    Guest

    Hi Engineer,

    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.

    #53859
    pix
    Guest

    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.

Viewing 4 posts - 1 through 4 (of 4 total)
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