Generic selectors
Exact matches only
Search in title
Search in content

C/I for GSM

  • This topic is empty.
Viewing 15 posts - 1 through 15 (of 15 total)
  • Author
    Posts
  • #38771 Reply
    bpong
    Guest

    can anyone confirm if C/I= 12dB for GSM?
    can I interpret that if I got a wanted signal at -90dBm, the interference cannot be higher than -102dBm?

    #38772 Reply
    Arindam
    Guest

    Hi,
    In GSM the acceptable value of C/I is 12dB or higher. Allthough some vendors say that with hopping even 9dB or higher can be acceptable.

    This means if your serving frequency (C) should be at least 12dB higher than the interferer(I).

    So if you have a serving ARFCN at -90, then the interferer should be at -102 or lower.

    #38773 Reply
    bpong
    Guest

    Does the interferer (I) mean co-channel ARFCN or adjacent channel?

    #38774 Reply
    Arindam
    Guest

    When you’re talking about C/I, it means co-channel. For adjacent channel , the relevant parameter is C/A.

    #38775 Reply
    Arindam
    Guest

    The term “I” indeed is the co-channel interferer. When we are talking about adjacent channel interference, the relevant parameter is C/A.

    #38776 Reply
    bpong
    Guest

    What’s the C/A value for GSM, offset at 1 channel & 2 channels away?

    #38777 Reply
    Arindam
    Guest

    Usually the recommended value of C/A is 3dB. This is an Ericsson recommended value.

    #38778 Reply
    bpong
    Guest

    Is it so low, 3dB? I thought it should be around 50-60dBc.

    #38779 Reply
    Arindam
    Guest

    Hi,
    I am afraid it is not 50-60. May be ,you could give me your mail id, I can send you a document dealing with C/A and C/I.

    #38780 Reply
    bpong
    Guest

    I just read the GSM spec.
    C/A @ 200khz = 9db

    #38781 Reply
    AliShah
    Guest

    Can anyone tell me the range of C/A in GSM ???? please……… m much confused

    #38782 Reply
    pix
    Guest

    h,

    C/A is just the C/I with I = the adjacent freq.

    an ok value is C/A > -9dB, for speech purposes.

    You can find all the thresholds you need in 45.003 i believe.

    regards
    pix

    #38783 Reply
    gm
    Guest

    When predicting C/Ic=9dB for the purpose of frequency planning, one must keep in mind that a prediction is a prediction. In reality, the measured value can be higher or smaller with a probability of 50%. Theoretical mathematical calculation can show more details. Therefore it is better to predict a value higher than 9dB, at least 12dB or 18dB or more.

    #38784 Reply
    gm
    Guest

    9dB is for speech.. EGPRS can require a C/I up to 30dB ! (mcs9)

    #38785 Reply
    festus
    Guest

    Am finding it difficualtto calculate the percentage of C/I while prepering report for ssv. could someone help me with the fomular?

Viewing 15 posts - 1 through 15 (of 15 total)
Reply To: Reply #38775 in C/I for GSM
Your information:




<a href="" title="" rel="" target=""> <blockquote cite=""> <code> <pre class=""> <em> <strong> <del datetime="" cite=""> <ins datetime="" cite=""> <ul> <ol start=""> <li> <img src="" border="" alt="" height="" width="">