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Co- & adjacent channel interference

Viewing 6 posts - 1 through 6 (of 6 total)
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  • #63356 Reply
    RiMi
    Guest

    Hey everyone,
    I am beginner in GSM tech , so having some doubts. Can anybody please explain me “Co-channel & adjacent channel interferce” .
    And how does cell identifies that which frequency is offering interference?
    Hi pix looking forward to see your reply.
    Thanx in advance…….

    #63357 Reply
    pix
    Guest

    hi rimi,

    as you know, one call is using one specific frequency during one/eight of the time.
    if somewhere else in the area, another call is using the same frequency during the same time, the first user will hear a degradation in the voice quality (robot voice).

    this is co-channel interference.
    2 calls using the same frequency, in the same area.
    if there are 8 users on the first frequency, and 8 users on the second frequency, you see that the probability of “collision” is very high.

    now, same scenario, except that the second user is using a frequency which is +200kHz or -200kHz compared to the 1st frequency. Here, the impact on the voice is much less : only if this “adjacent” frequency is very very strong, then the first frequency will be “eclipsed” and the first subscriber will hear a bad voice quality (still the robot voice).

    the cell doesn’t identify the interference, it is up to the optimizer to find which frequencies are conflicting.

    cheers
    pix

    #63358 Reply
    RiMi
    Guest

    Thanx a lot Pix for your quick response,
    can you please tell me how does optimizer find this out, that which frequency is interfering with the original one?

    Regards,
    RiMi

    #63359 Reply
    pix
    Guest

    by checking which cells are using the same frequency in the vicinity, on the map, and trying to guess which one is actually propagating up to where the intereference was detected.

    regards
    pix

    #63360 Reply
    RiMi
    Guest

    Hey pix…

    i wanted to knw which BCCH frequency is interfering with the oiginal one….? how would optimizer find this? could you please tell me abt the procedural steps is there is any!!!

    Thanx for all your response and help!!!!!!!!!

    Regards,
    RiMi

    #63361 Reply
    pix
    Guest

    hi,

    this is what i’ve explained in my previous post..

Viewing 6 posts - 1 through 6 (of 6 total)
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