Channel state information

Channel state information is information about the current value of H, a mathematical value which represents a signal channel. It forms part of the signal model in Wireless communications, the full equation of which is

R = H X + N

where R is the received signal, X is the transmitted signal, N is the noise, and H is the channel. Wireless communication is the transfer of information over a distance without the use of electrical conductors or " Wires quot The values R, X, N, H are usually not constant. The system usually needs to have some information regarding H to figure out what was sent from the transmitter or to enhance system performance, such as increasing transmission speed. In Telecommunications and Computing, bitrate (sometimes written bit rate, data rate or as a Variable R or f b The information can be the current value of H, or the covariance of H. Information as a concept has a diversity of meanings from everyday usage to technical settings In Probability theory and Statistics, covariance is a measure of how much two variables change together (the Variance is a special case of the covariance This type of information is generally referred as channel state information (CSI) and is usually estimated. Estimation is the calculated Approximation of a result which is usable even if Input data may be incomplete or uncertain. Usually the current value of H is referred as short-term CSI, while the higher order statistics of H are referred as long-term CSI.

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