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MULTIBAND & COMMON BCCH

Viewing 12 posts - 1 through 12 (of 12 total)
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  • #63070 Reply
    YASUKA
    Guest

    Hello Everybody,

    We are using 2 vendor, Nokia&E/// in our network. And mainly DCS1800 cells, and we have around new 15 GSM900 frq now. Thus we are planning to use these new 900 frq effectively.

    Could you help me on this? How, where can we use 900 frq well?

    * There is such features, Multiband or common BCCH, inner outer.. vendor specific.. and main approach on this, 900 for coverage, 1800 for traffic

    If I use common BCCH feature and;
    900-BCCH (outer)
    1800-TCH (inner)

    and I will try to push traffic to 1800-TCH then, so what is the meaning to make coverage with 900 if I will push traffic to 1800? If we accept 10/13 db difference between 900&1800, so 1800 coverage*signal always will be less than 900 where we have coverage but shifting traffic to 1800 trx..

    I am little confused here??

    If I am gonna push traffic to 1800 trx, why I need to make coverage with 900?? and this coverage for what if we dont use for traffic??

    PS. If I use common bcch or multiband, how Hopping works? possible to have SFH between different band frq?

    Thanks & BR

    #63071 Reply
    naveen
    Guest

    You must remember that 900 band gives better coverage compared to 1800 band, hence RF guys usually use 900 for coverage and 1800 for capacity. I am not really sure how effective this technique is.

    #63072 Reply
    Ali
    Guest

    We can use the MultiBand in the network in order to reduce the use of frequency 900Mhz. it’s commonly known that 900 coverage is big than 1800Mhz coverage so the 1800 band should serve for capacity and 900 layer should serve coverage, access and Handover.
    there are many parameter to manage the trafic between this two layers for example nonBcchLayerAccessThr and nonBcchLayerExitThr and nonBCCHlayerOffset
    I can helpe you if you provide me with sufficent data about your network site location trafic and ….

    #63073 Reply
    yasuka
    Guest

    Thanks Naveen & Ali

    if we make config like;
    BCCH=1800 (UL)
    TRX2=1800 (UL)
    TRX3=1800 (UL)
    TRX4=900 (OL)
    TRX5=900 (OL)

    * I prefer to make 900 band as non-bcch and overlaid (OL) due to limited frq, only 10 frqs. Because I can not make good BCCH plan with such less frqs.

    And using synthesizer Hopping;

    TRX2 & TRX3 will be hopping in MA list or CHG of 1800 frq ( min 2 frqs)

    and TRX4 & TRX5 will be hopping in MA list of 900 frq (min 2 frqs)

    Is that right? But we lost Hopping gain due to only 2 frq per band.

    Because if we use only 1800 band and 4 frq in MA hopping list, that will better performance.

    I know that its possible to give priority or make more attractive of any band, 900 or 1800 with parameters like taking traffic from 900 trxs until they are full and then 1800 trx will get traffic or vice versa.

    #63074 Reply
    nevy_14
    Guest

    Hi Yasuka,

    i see that you have a little GSM900 bandwidth.try to use MBC(E//) or Co-BCCH(Nokia) feature, you can use all your GSM900 as your BCCH freq. then you used all the remaining DCS1800 in your MA list (SFH).
    GSM900 in term of coverage, DCS1800 in term of capacity.
    You can tune the load balancing parameter so that if the GSM900 is fully occupied than the call can be transferred to DCS1800.

    BR,
    nevy_14

    #63075 Reply
    Mania
    Guest

    Hi,
    yup you are in a fix alright…
    @yasuka:
    Well you can use the cell in that configuration but then you would have to define the cell as single cell and use different FHS’s.
    But as the no of such sites increase the noise floor on your GSM would increase, and KPI degrade grately and you would not have that specific control on traffic assignment to different band cells. what is the optimal if you do insist to go with your config. is to use lower power on GSM TRXs or down tilt it severely as compared to DCS and assign lower priority to TRXs of GSM all these would reduce the noise floor of GSM so your KPIs would not be effected to that extent.
    I would say nevy_14’s option is better and you can use it only on cells where you have blocking (not even all sectors to have GSM + DCS)add GSM BCCH and one hopping radio, assign fixed specific frequencies in SFH no 1×1 or 1×3 like stuff.

    #63076 Reply
    barham
    Guest

    hi, i have two quastions ,first if we use common BCCH between 900 and 1800 , there be Hand over between 900and1800 or we do not need to add each of them as aneighbor any more , i know this both will be configuredon the smae cell but some times subscribers are going to be on DCS in dedicated mode , my second quastion is that is there any parameter to return back the subscriber to be on 900 to know how is the RX-Level and quality of 900

    #63077 Reply
    sar
    Guest

    hi,

    we can define 2 bcch for one cell in ericsson BSC

    #63078 Reply
    Ravi
    Guest

    Hi,

    I am facing issue in an IBS site where same feeder line is being used for 2 different operators.
    one is operating on 900 and other is on 1800 band. 900 band is using Nokia & 1800 band is using Ericsson equipment.

    Problem is that 900 is having poor RX level (-90) whereas 1800 is having good RX level (-56).

    what can be the possible cause while there is no alarm in Nokia BTS.

    #63079 Reply
    roshan jha
    Guest

    Dear sir

    why are you not using 900 band is 4 TRx.
    then why are you not using in 900Band s more then 4TRx

    #63080 Reply
    vikash gupta
    Guest

    how to define handover between two master 900 and 1800 band that belong to different site.

    #63081 Reply
    LOTFI
    Guest

    HI EVERY BADY IM NEW ENGINEER AND I WANT TO BE LIKE YOU
    what is mean COBCCH

Viewing 12 posts - 1 through 12 (of 12 total)
Reply To: MULTIBAND & COMMON BCCH
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