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Frequency Hopping System

Viewing 15 posts - 46 through 60 (of 118 total)
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  • #41312 Reply
    KayDee
    Guest

    Hi Guy!

    I have in our network implemented SFH, we had 60 frquencies to use. i put aside 30 frequency for hopping (10 *3). the gurd bands between other operators and hopping and BCCH frequency were taken from the remaining 30(BCCH frequencies + GB). for me i had to reserve 10 frequencies per sector because we have high configuration sites which give us up to six TRX’s per sector. as you said gurdbands are very importnt otherwise you will have interference between you BCCH and Hopping channels. do not forget to adjust you quality power control and handover threshold after implementing SFH….

    #41313 Reply
    siva
    Guest

    Why GSM Frame has only 8 Time slots?( why not any number like 10 to cater for more people or 6 to cater for better quality)

    How the bit period is 48/13 microsecs( or 156.25 bits in 577 micro secs)

    #41314 Reply
    M.Thyagarajan
    Guest

    Hey siva,

    You know the bandwidth of the GSMK filter is 67.5 and the output of the mobile is at 270.333 .Divide 270 by 67.5 you get 4 i,e you would need 4 channels in UL and 4 channels in DL thus giving u 8 timeslot per TRX.

    Regards
    M.Thyagarajan

    #41315 Reply
    Boko
    Guest

    If you change from BBH to SFH do you adjust power control/handover thresholds?

    rgds

    #41316 Reply
    M.Thyagarajan
    Guest

    Boko,

    The thresholds for handover donot change as the handover is based on the BCCH measurements and not the TCH measurements , while the power control thresholds for quality need to be modified as the quality measured will be less.

    #41317 Reply
    KayDee
    Guest

    The thresholds for quality handover must be adjusted as well. You do not measure those thresholds on BCCH, you measure them on the TCH that you are using. If you do not change them to a slightly higher value(4 to 5 or 6) you up/down link quality handovers will be three to four times compared to before you implement SFH.

    #41318 Reply
    jood
    Guest

    M.Thyagarajan
    BCCH mesearment has just involved in HO performance in one way (the way of ranking the candidate neighbouring cell to do HO locating on it)
    KayDee
    you right, SFH have great effect on Quality improve, so threshld of qual HO & PBGT need to modified.

    #41319 Reply
    SACHIN GUPTA
    Guest

    CAN SOMEBODY EXPLAIN IN DETAIL ABOUT HSN AND MAIO????????? URGENT
    THANX
    SACHIN

    #41320 Reply
    akoko-oluwa
    Guest

    Why GSM Frame has only 8 Time slots?( why not any number like 16 to cater for more people and for better quality)

    can somebody explain erlang to me or recommend text books which i can read

    #41321 Reply
    KayDee
    Guest

    Hi Guys!

    While we are still on this topic. I have succesfully implemented SFH on 1800 few months ago. Now it’s time that I do the same for 900, but we had a very big problem with CSSR. We have mixed EGSM and PGSM frequency on one MA list. Does anybody know if mixing these frequencies is a problem and if it is why? We are using Siemens PD DUAMCOs and FDUAMCOs.

    #41322 Reply
    yasser
    Guest

    Hi Every one !
    i have been assign a project about studing of cdma. kindly help me weblinks about it.

    #41323 Reply
    Alain
    Guest

    Hi guys,

    If you want to use the Frequency Hopping Synthesizer for GSM base stations, you should ask THine electronics in Japan.

    contact point is sales@thine.co.jp

    Web is http://www.thine.co.jp/index_e.html

    Just one person has many experience for GSM frequency hopping system and hopping synthesizer!

    #41324 Reply
    anand
    Guest

    hello guys,

    tell me the working procedure of frequency counter

    #41325 Reply
    Shekar
    Guest

    Hi thyagarajan,

    May i know your email id ?, you seem to have a indepth knowledge on RF parameters. By the way You had replied to Mr. Siva’s question,
    You know the bandwidth of the GSMK filter is 67.5 and the output of the mobile is at 270.333 .Divide 270 by 67.5 you get 4 i,e you would need 4 channels in UL and 4 channels in DL thus giving u 8 timeslot per TRX.
    Now tell me what is this 270.333 ? is output power of the mobile (tx pwr is 33 dBm) or is it some thing else you are referring to ?? You can mail me at shekar.pk@gmail.com

    #41326 Reply
    jood
    Guest

    You said((the bandwidth of the GSMK filter is 67.5 and the output of the mobile is at 270.333 .Divide 270 by 67.5 you get 4 i,e you would need 4 channels in UL and 4 channels in DL thus giving u 8 timeslot per TRX)).
    So there is inconsistency, Cuz 67.5 is Hz , & 270 is kb/s.
    Thus 270 is just compatible with 67.5 to produce four status on I/Q modulating diagram (00, 10, 11, 01).
    Regards

Viewing 15 posts - 46 through 60 (of 118 total)
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