Carrier-to-Noise-and-Interference Ratio

This MedLibrary.org supplementary page on Carrier-to-Noise-and-Interference Ratio is provided directly from the open source Wikipedia as a service to our readers. Please see the note below on authorship of this content, as well as the Wikipedia usage guidelines. To search for other content from our encyclopedia supplement, please use the form below:

The signal-to-interference ratio (S/I or SIR), also known as the carrier-to-interference ratio (C/I, CIR), is the quotient between the average received modulated carrier power S or C and the average received co-channel interference power I, i.e. cross-talk, from other transmitters than the useful signal.

The CIR resembles the carrier-to-noise ratio (CNR or C/N), which is the signal-to-noise ratio (SNR or S/N) of a modulated signal before demodulation. A distinction is that interfering radio transmitters contributing to I may be controlled by radio resource management, while N involves noise power from other sources, typically additive white gaussian noise (AWGN).

The CIR ratio is studied in interference limited systems, i.e. where I dominates over N, typically in cellular radio systems and broadcasting systems where frequency channels are reused in view to achieve high level of area coverage. The C/N is studied in noise limited systems. If both situations can occur, the carrier-to-noise-and-interference ratio, C/(N+I) or CNIR may be studied.

See also

Wikipedia content modification information:

  • This page was last modified on 17 July 2008, at 04:00.

Wikipedia Authorship and Review

Wikipedia content provided here is not reviewed directly by MedLibrary.org. Wikipedia content is authored by an open community of volunteers and is not produced by or in any way affiliated with MedLibrary.org.

Wikipedia Usage Guidelines

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article on "Carrier-to-Noise-and-Interference Ratio".

The URL for this specific entry is:

All Wikipedia text is available under the terms of the GNU Free Documentation License. (See Copyrights for details). Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc.