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Same (BCCH, BSIC) couple

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  • #54065 Reply
    Pix
    Guest

    Ali,

    Gotcha ! The full BSIC is included in the encrypted bits of the RACH :

    =========================

    3GPP 45.003, chapter 4.6 & 4.8

    The six bits of the BSIC, {B(0),B(1),…,B(5)}, of the BS to which the Random Access is intended, are added bitwise modulo 2 to the six parity bits, {p(0),p(1),…,p(5)}. This results in six colour bits, C(0) to C(5) defined as C(k) = b(k) + p(k) (k = 0 to 5) where:
    b(0) = MSB of PLMN colour code
    b(5) = LSB of BS colour code.

    =========================

    Bijoy,

    Friendly is good, don’t worry ๐Ÿ™‚
    I just get a little suspicious when someone is trying to drink me. Because first, you need to liquify me. Not a pleasant experience…

    #54066 Reply
    AliAsgher
    Guest

    Thanks Pix for the valuable information. I am sorry I was wrong on this.

    “Liquifying Pix”… Could well be a title of some Telecom related book. ๐Ÿ™‚

    #54067 Reply
    Pix The Liquified Geek
    Guest

    It is good to do mistakes, that’s the only way to learn ๐Ÿ™‚

    And that’s the only way to make me look better ;-))))

    #54068 Reply
    Bijoy
    Guest

    Pix/Ali
    Just adding some more info.
    There is a feature called “Soft Syncronisation” in which neighbouring cells can have BCCH & BSIC,the only thing different will be the frame offset.

    Ali
    In Ericsson it is called Syncronised Radio networks

    #54069 Reply
    AliAsgher
    Guest

    Dear Bijoy,

    If neighbor cells have got same BCCH, regardless of their BSIC, there will be no handovers between them.

    The feature Synchronized Radio Networks is just a name for HSN, MAIO and FNOFFSET planning.

    I very much doubt that there is any possibility in GSM systems to survive with Co-BCCH/BSIC neighbors.

    Because any feature can be applied on BSC/BTS level but MS will continue to measure the neighbors the same way and I dont think that by any kind of framing offset the MS can know who is who. (If both WHOs have got same BCCH)

    Please correct me. Cause I am really curious about this.

    Regards,

    #54070 Reply
    Bijoy
    Guest

    Hi Ali
    I’m not talking about a cell having same BCCH-BSIC neighbours.
    I was talking about a cell which has a same BSIC-BCCH cell in its vicinity say(>1.5 Km) & not defined as a neighbour,but can be a potential interferer.

    Br\\
    Bijoy

    #54071 Reply
    Pix
    Guest

    Hi,

    Network synchronization will help decreasing the C/I, especially in case of SFH 1×1 or 1×3. The point here is to increase the capacity of the network (better C/I means the network can actually accept more traffic before soft blocking)

    It will not allow neighbours with same BCCH ! That would be a magic trick.
    co-BCCH neighbours are still forbidden.

    Cheers,
    Pix

    #54072 Reply
    Bijoy
    Guest

    Hi Pix
    Did I created some confusion??
    My intention was to say that using syncronised Networks,a good TSC planning will actually bring down the N/W interference,even this there is tighter BCCH reuse

    Br\\
    Bijoy

    #54073 Reply
    Bijoy
    Guest

    Also
    I didnt get that how C/I will decrease with syncronised radio n/ws

    #54074 Reply
    AliAsgher
    Guest

    Dear Bijoy,
    Your previous statement was confusing for me. With your later post I got your point.

    Pix,
    Actually C/I should increase when this feature is used.

    #54075 Reply
    Pix
    Guest

    When I said “Decrease C/I” I meant “Decrease interference”.
    But you both corrected yourself. Com’on, what kind of feature is going to decrease the C/i ??? :))

    Bijoy,
    You said “same BSIC-BCCH cell in its vicinity say(>1.5 Km)”

    The problems generated by co BCCH BSIC are not cancelled by NW Synchro. (RACH collisions, CHANNEL REQUESTS understood by both cells, HO ACCESS understood by both cells, etc)

    NW Synchro is going to decrease TCH interference, and also speed up the HO intercell, but that’s about it. As far as I understand it.
    (Indeed, ALU is just starting to propose this feature in the new B11 release !)

    #54076 Reply
    Bijoy
    Guest

    Pix
    The thing you meant by “decrese C/I” is not so obvious.It is rather the reverse.

    Regarding Co-BSIC BCCH,I never said that it is going to cancel its effect entirely,but it will definitely improve the n/w C/I by planning different TSC’s for the hopping TRX’s.
    For networks having tighter BCCH BSIC reuse,it works quite good.
    Also how does N/w sync speed up intercell HO??

    Br\\
    Bijoy

    #54077 Reply
    Pix
    Guest

    Bijoy,

    Well, you talked about BCCH/BSIC. You shouldn’t have ๐Ÿ™‚

    The HO intercell will be executed faster than before : both serving cell and target cells are synchronized.

    (do I need to explain further ?)

    Synchronous HO are faster than Asynchronous HO, because there is no need for the MS to resync with the new cell. Less messages….

    #54078 Reply
    Bijoy
    Guest

    Pix
    I’m still talking about BCCH/BSIC.What did I else be meaning by saying “tighter BCCH reuse”.If you are alloted less B/W,will you be of course be offered less NCC as well(TRAI guideline).

    Regarding synconised n/w,i think you get confused with syncronised neighbours.
    Even if you say for sync neighbours,the only benefit you get is that MS doesn’t need the TA in the phy info message,thats it.As far as tuning to the target cell is concerned,the process & time is similar than that of a non sync HO.The messages are not lesser,the content becomes redundant only

    Br\\
    Bijoy

    #54079 Reply
    AliAsgher
    Guest

    I agree Bijoy, MS will still have to get Sync burst from neighbors to get idea about TA. Handover times should not be reduced.

Viewing 15 posts - 16 through 30 (of 37 total)
Reply To: Same (BCCH, BSIC) couple
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