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ALU Drop Radio

Viewing 15 posts - 16 through 30 (of 32 total)
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  • #63770 Reply
    biodun
    Guest

    pls can anyone help me with stuffs on Atoll+wiamx+TEMS.thnks

    #63771 Reply
    ALU
    Guest

    Hi Pix,
    DFH is a type of SFH in which
    no of Frequencies >= no of TRX
    You dont have to assign a complete hopping group to each cell like in normal SFH.Its more of similar to BBH.Kindly note that its not necessarily used for cells which have little amount of TRX.Its equally beneficial for high configuration cells aswell.
    Example:
    Consider Frequency Band from 500-532(TCH) and 534-550(BCCH)ARFCN and a 4-TRX cell.
    Lets just say that you are implementing DFH with
    NO of Frequencies=No of TRX
    So, you can have a scenario like:
    Cell A= 534, 500,531,515
    Cell B= 550, 504,512,518
    Cell C= 546, 506,510,520
    So, you see here the plan is just like BBH except for the fact that the whole BCCH TRX doesnt hop.Its more beneficial when you assign more frequencies than the no of TRXs.So, mostly for low configuration sites(2-TRX) , you can assign 4 frequencies and reap the advantage of DFH ๐Ÿ™‚
    I was curious about a statement of urs that
    “most calls will be allocated on 2nd trx ” why do u say that? Has Alcatel removed the parameter “pref-mark” in your Release or you dont like playing with it(pm)? ๐Ÿ˜›
    You are right about the SDCCH ๐Ÿ™‚

    #63772 Reply
    pix
    Guest

    ok about dfh, it’s clear ๐Ÿ™‚
    the pref mark is fantastic, as long as you don’t have GPRS traffic… so no, i don’t like playing with it. Anyway, default behaviour is fine, no need to play with pref mark in this situation.

    en_ma_selection is sufficient too (cf. other thread) to put MS on the hopping TRXs rather than on the BCCH TRX.

    thanks for the enlightening discussion ๐Ÿ™‚

    pix

    #63773 Reply
    Mickey
    Guest

    Here what if i keep pref_mark as 0 for all the TRX, or what is recommended?

    #63774 Reply
    pix
    Guest

    i used to keep 0 for all TRXs, that’s what i would recommend on a standard network.
    only in some case of exotic use of SFH (different MA list per TRX) or in case of faulty TRX troubleshooting, changing the trx pref mark is interesting.

    (just my opinion…)

    pix

    #63775 Reply
    ALU
    Guest

    Hi Pix,
    Well i personally feel that apart from Faulty TRX troubleshooting ,prefmark can be very useful at times even if u r having normal SFH(1*1 or 1*3).At places where the azimuths are not standardized and hopping frequencies are very much interfered due to overlapping of coverage area of diff cellshaving same FHS(and there r plenty of such cases in my current network and operator doesn’t allow redesign :P)…you cannot do much as whenever the call goes on hopping, the Rxqual degrades(6,7).So, simple solution is to push traffic to the BCCH TRX by just change of PM ๐Ÿ™‚
    Vice versa is also applicable at certain cases.

    #63776 Reply
    Mania
    Guest

    Just curious from the below discussion.
    |How can FH (Frequency hopping increase coverage area) also coverage area of the cell usually defined by BCCH TRX (for call setup and handover).
    Also ALU you case seems ideal for BBH trial and should be good for your network then why not proceed for BBH? should have great improvement in KPIs

    #63777 Reply
    Pix
    Guest

    Hi all

    ALU
    are you saying That Prefmark is useful to avoid calls going on anything else than bcch trx? Well, ok i call that a very specific situation ๐Ÿ™‚ as mania said it might be Time to use bbh.

    Mania,
    the initial access is done on bcch ts0 but it is so short that even with low rxlev it could go through. But call setup (sdcch) and call (tch) are long and require a good average lev. Freq diversity can help improving lev by fighting rhe fast fading.

    Regards

    #63778 Reply
    paul
    Guest

    dear Pix,

    My network is using FSH 1×3, not BBH, only few sites are using BBH (outside inner city).

    Well, as we know, FSH means that the frequency which will not be hoped is only the BCCH frequency, which mean it’s located in TRX-1 (Usually). Other TRXs (2,3,4), the frequencies are hoped (Each of TRX 2,3,4 has different MALIST).

    In my network, sector 1 & 3 will be hoped periodically based on MAIO 0,2,4 and sector 2 MAIO 1,3,5.

    Your explanations is related to BBH, if I’m not wrong ๐Ÿ™‚ But my case is in FSH (Frequency Synthesize Hopping).

    Based on my experience, if I extend MALIST by adding some frequecny channel from BCCH range Frequency and change the MAIO, it improved the performance (SD Drops, Drop Call). And even though like that (Putting BCCH frequency in MALIST),it seems no inner interference happened. It’s true, you can try it.

    Any idea Pix?

    By the way, if you are from France, it seems that you graduated from ALCATEL University :):):)

    Regards,

    Paul

    #63779 Reply
    ALU
    Guest

    yes pix, its really helpful in certain scenarios and as suggested by you & Mania, we are going for BBH…just waiting for Operator to finalize the details and go ahead with the plan!

    #63780 Reply
    Mania
    Guest

    Hi pix (though he is on leave):) / anyone with info.
    regarding your previous explaination on how FH can improve coverage

    “the initial access is done on bcch ts0 but it is so short that even with low rxlev it could go through. But call setup (sdcch) and call (tch) are long and require a good average lev. Freq diversity can help improving lev by fighting rhe fast fading.”

    Then how come we prefer keeping SDCCH on BCCH TRXs, here the concept is that keep SDCCH on BCCH as it would be cleaner (and is planned cleaner). seems like the two concepts are contridictory to each other.

    #63781 Reply
    pix
    Guest

    paul,

    i didn’t understand your question. What are you asking exactly ?

    (ps: ha ha, i never needed to graduate : i work there ! ๐Ÿ™‚ )

    mania,

    trx1 provides better rxqual due to better frequency planning
    trx 2, 3… provide better rx lev due to frequency diversity (if FH is activated), but this is not always true, and hard to quantify anyway.

    if bbh is activated, trx1 can also get frequency hopping (except ts0)

    so why SDCCH and BCCH on TRX1 : because rxqual is better, therefore less interference. (that’s a measurable improvement, whereas freq diversity is hard to measure)

    regards !
    pix

    #63782 Reply
    Mania
    Guest

    Thanks Pix,
    You Just added valuble gems to my vault. ๐Ÿ™‚
    @ ALU: Glad to be of help, hope I was in your network, my current opperator is severely undermining BBH implementation even when we have shown great improvement, just because of Planning overload added by BBH.

    #63783 Reply
    ALU
    Guest

    Hi Mania,
    Why don’t you opt for DFH(Discrete Freq Hopping) then? because its very similar to BBH and secondly no planning overload ๐Ÿ™‚

    #63784 Reply
    pix
    Guest

    alu,

    dfh requires as much planning effort than the bbh, since you need to assign a specific FHS to each sector ๐Ÿ™‚

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