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C/I vs C/N | difference between C/I measurement, C/N measurement

This page compares C/I vs C/N and mentions difference between C/I measurement and C/N measurement. C/I stands for carrier to interference ratio and C/N stands for carrier to noise ratio.

C/N measurement

C/N Ratio

• C/N is used to indicate ratio of power in single RF carrier with the noise power in the channel.
• C/N indicates the difference between desired RF carrier amplitude and noise level in part of the spectrum.
• C and N may be measured in watts or in volts squared. There are other units such as dBm and dBW also.
• The C/N measurement allows us to analyze if carrier signal can be recognized as such or it is obliterated by ambient and system noise power.
• It provides value for the quality of the communication channel.
• The quality of the system is determined through BER versus C/N plots.

C/N Ratio example

C/N ratio Example:
The figure-2 depicts QPSK signal interfered by ambient white noise.
➤C/N ratio = (-32.5) - (-48) = 15.5 dB

C/I measurement

C/I Ratio

• C/I is used to indicate ratio of power in single RF carrier to interference power in the channel.
• C/I measurement allows analysis and rating of channel robustness against neighbor channels.
• C/N, C/No and C/I are analyzed using BER plots.

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