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TRX TS …

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  • #67541
    Amit
    Guest

    HI,

    Why 1 TRX has only 8 TS…

    it is because of TDMA frame structure , GSM Standard or any other pls share…

    #67542
    Soly
    Guest

    HI Amit,
    1 TRX has 8 traffic channel, and each 4 channels need 1 TS, so you need 2 TS for each 1 TRX for Traffic only,

    about RSL, it depend on Multiplexing mode if you are using MUX2_1 so you need 2.5 TS for each TRX

    #67543
    SHELDON
    Guest

    Hi Amit,

    That is a very tough question.

    I think it has to do with the data rate you can get with GMSK, which is the modulation used in GSM.

    With a bandwidth of 200kz and GMSK modulation, you can get a gross bitrate of 270kb/s. Into how many “slots” can you divide this so that you can still have effective communication? Well, according to the people who designed GSM,the optimum is 8.

    270/8 gives 33.75kb/s, and considering that a full rate speech coder requires 13kb/s, you have more than enough overhead to add protection/coding bits.

    Hope you’re convinced.

    PS: I’m not convinced myself. ๐Ÿ˜€

    SHELDON

    #67544
    pix
    Guest

    but you should be convinced that this is a useless question ๐Ÿ™‚

    so, in this regard, your answer is probably the best that can be given ๐Ÿ˜€

    on top of what you said, if you add “idle” time (guard periods, Training Seq Codes) you’ll see that each TS has a throughput of 22 kb/s. Which is indeed just enough to get a good codec (old FR = 13kb/s) + a protection that keeps the rxqual < 4 when C/I = 9dB. Now, why is the bandwidth 200kHz ? ๐Ÿ˜€ (another very useless question) ๐Ÿ˜‰ Friendly Cheers ! pix

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