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What is BSIC?

Viewing 15 posts - 1 through 15 (of 35 total)
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  • #35812 Reply
    Nguyen
    Guest

    Hi everyone,
    Could anyone tell me what does BSIC mean?
    Thanks a lot.

    #35813 Reply
    Nic
    Guest

    BSIC -> Base station identity code. this has importance when you cross national boundaries.. well that is the time u have two identical bcch frequencies for a single mobile request.

    BSIC is broadcast as part of SCH.
    two cells can have identical BSIC in a network but not the neighbouring cells.. Always H PLMN nad adjoining PLMN BSIC’s are different according to the agreement..

    Hope it clarifies.

    #35814 Reply
    Nguyen
    Guest

    Thank you very much for your information. However, why we need the BSIC while we already have the Cell ID, that can be used to distinguish between 2 cell?

    #35815 Reply
    Nguyen – vndnguyen@hopthu.com
    Guest

    Ohhhhh, I have found an answer for myself, but Im not sure 100%.

    BSIC is used by MS in dedicated mode, for handover procedure. Cell ID is used by MS in idle mode, for cell selection procedure.

    If anyone have other idea, plz let me know. Thanks!!!

    #35816 Reply
    Dimapl
    Guest

    Hi, Nguyen! BSIC consists of two 3-bit coded parts: NCC and BCC. NCC stands for Network color code, BCC – base station color code. BSIC planning is a part of RF planning. BSIC decoding helps mobile to distinguish between two cells if they use the same frequency channel. NCC part must be always in line with the parameter PLMN_permitted which is broadcast on BCCH. It means that NCC value must be in the PLMN_PERMITTED list otherwise mobile will not be able neither to camp on cell nor make a handover.

    #35817 Reply
    Nguyen
    Guest

    Hi Dimapl,

    This information is new and very useful for me.

    Do you know if it is permitted to have multiple NCC within one PLMN?

    By the way, why we still need the BSIC while we already have the Cell ID, that can be used by the MS to distinguish between 2 cells with the same BCCH frequency?

    Regards,

    #35818 Reply
    Dimapl
    Guest

    Hi Nguyen,
    The usage of multiple NCCs should be agreed between operators that provide service in the same location. From technical point of view it is possible to use multiple NCCs and it works fine. But don’t forget PLMN_PERMITTED otherwise you’ll face many problems and subscriber complaints!
    When mobile station is in dedicated mode it performs periodical measurements of received signal level and quality of the serving cell as well as received signal level of adjacent cells. Hereafter mobile selects six best adjacent cells and reports them back to the network. The measurement report consists of BSIC,BA list index and received signal level of six adjacent cells. If mobile is not able to retrieve BSIC, the measurement result will be considered as invalid. Network element that processes measurement results (BSC or BTS, vendor dependent) checks the combination of BSIC and BA list index against adjacent cells database and converts it into CELL ID of the adjacent cell. If the convertion fails due to wrong BSIC it means that mobile has detected a signal from an undefined adjacent cell that uses the same frequency channel and the measurement result will be discarded.

    #35819 Reply
    Nguyen
    Guest

    Hi Dimapl,

    Thank you very much for your information. However, I still want to know, why the MS does not use the Cell ID instead of BSIC for the adjacent cells in the measurement report it sent to the network?

    Another question about handover: As you may know, the handover procedure preserves call connection as MS move from one radio coverage area to another during a call. Do you think the MS may perform handover from cell A of its home PLMN to cell B of another PLMN (i.e. roaming and then handover without interrupting the call)?

    Kind regards.

    #35820 Reply
    Mathew
    Guest

    Hi Hyugen,

    As explained earlier CellID is not sent on Measurement Report from the MS to the BSS -ONLY BSIC is sent ref : GSM 4.08 sec10.5.20.

    For Handover between PLMN , MAP-E inter MSC Handovers are used.

    #35821 Reply
    Nguyen
    Guest

    Hi Mathew,

    I know that there is only BSIC in Measurement Report as defined in recommendation GSM 04.08. But why does not MS send Cell ID instead of BSIC? I think if the MS sends the Cell ID in the measurement report, the information about neighbour cells will be more clearly and we do not need BSIC anymore (???)

    Thank you for information about handover between PLMNs. Could you give me some more information about MAP-E? Which document/recommendation may I refer?

    Thanks again.

    #35822 Reply
    Dimapl
    Guest

    Hi Nguyen,
    CELL ID decoding is very much time consuming. In order to read Cell ID from BCCH MS needs to adjust its frequency from FCH, to lock its phase by means of extended training sequence contained in SCH. After that MS is able read System information messages from BCCH. System information is not sent as often as SCH. In dedicated mode ,as you definetly know, MS has only 3,9 ms between successive TDMA slots and there is a lot of job to be done for the mobile within this time period. I think that is the reason for using the combination of BSIC and ARFCN for cell identification.

    #35823 Reply
    Nguyen
    Guest

    Hi Dimapl,

    Thanks a lot for an informative answer. I think this is a real reason.

    A how about handover procedure between different PLMNs? Do you think what process to be happen first, roaming or handover?

    Thanks/regards

    #35824 Reply
    Dimapl
    Guest

    Hi Nguyen,
    Take a look at GSM specs 03.09 ( inter-MSC handover), 09.02 (MAP), 09.10 (MAP). There should be an E-interface between MSCs for inter-PLMN handover. According to specs inter-PLMN handover doesn’t differ from ordinary inter-MSC handover. Thus handover happens first then MS makes LU.

    #35825 Reply
    Nguyen
    Guest

    Dimapl,

    Thank you for your attention. You are right that, in the case of ordinary handover within an PLMN, the handover procedure happens first, and MS will make LU after the call is finished. However, in the case when the MS is roaming to another PLMN, the roaming procedure have to processed first in order to check whether the location area of VPLMN is allowed of roaming or not, AND whether the MS roaming subscription has been registered at its HPLMN or not. Is there something conflict in this situation?

    Brgds

    #35826 Reply
    Walter
    Guest

    BSIC: Base Transceiver Station Identity Code
    • used to distinguish neighboring base stations
    • two components:
    • Network Color Code (NCC)
    • Base Station Color Code (BCC)
    • directly adjacent PLMN and BS must have different color
    codes
    • The BSIC is broadcast periodically by the BTS on the SCH.

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