- This topic has 14 replies, 1 voice, and was last updated 5 years, 7 months ago by festus.
5th August 2004 at 10:21 #38771bpongGuest
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?9th August 2004 at 06:00 #38772ArindamGuest
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.10th August 2004 at 01:43 #38773bpongGuest
Does the interferer (I) mean co-channel ARFCN or adjacent channel?10th August 2004 at 03:48 #38774ArindamGuest
When you’re talking about C/I, it means co-channel. For adjacent channel , the relevant parameter is C/A.10th August 2004 at 07:01 #38775ArindamGuest
The term “I” indeed is the co-channel interferer. When we are talking about adjacent channel interference, the relevant parameter is C/A.10th August 2004 at 10:43 #38776bpongGuest
What’s the C/A value for GSM, offset at 1 channel & 2 channels away?11th August 2004 at 04:25 #38777ArindamGuest
Usually the recommended value of C/A is 3dB. This is an Ericsson recommended value.11th August 2004 at 04:54 #38778bpongGuest
Is it so low, 3dB? I thought it should be around 50-60dBc.12th August 2004 at 06:13 #38779ArindamGuest
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.15th August 2004 at 01:54 #38780bpongGuest
I just read the GSM spec.
C/A @ 200khz = 9db4th March 2013 at 07:41 #38781AliShahGuest
Can anyone tell me the range of C/A in GSM ???? please……… m much confused4th March 2013 at 18:10 #38782pixGuest
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.
pix13th March 2013 at 10:07 #38783gmGuest
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.13th March 2013 at 20:00 #38784gmGuest
9dB is for speech.. EGPRS can require a C/I up to 30dB ! (mcs9)2nd August 2015 at 12:22 #38785festusGuest
Am finding it difficualtto calculate the percentage of C/I while prepering report for ssv. could someone help me with the fomular?