In
Information theory
Information theory is the mathematical study of the quantification (science), quantification, Data storage, storage, and telecommunications, communication of information. The field was established and formalized by Claude Shannon in the 1940s, ...
, outage probability of a
communication channel
A communication channel refers either to a physical transmission medium such as a wire, or to a logical connection over a multiplexed medium such as a radio channel in telecommunications and computer networking. A channel is used for infor ...
is the
probability
Probability is a branch of mathematics and statistics concerning events and numerical descriptions of how likely they are to occur. The probability of an event is a number between 0 and 1; the larger the probability, the more likely an e ...
that a given information rate is not supported, because of variable
channel capacity
Channel capacity, in electrical engineering, computer science, and information theory, is the theoretical maximum rate at which information can be reliably transmitted over a communication channel.
Following the terms of the noisy-channel coding ...
. Outage probability is defined as the probability that information rate is less than the required threshold information rate. It is the probability that an outage will occur within a specified time period.
Slow-fading channel
For example, the channel capacity for slow-
fading channel
In wireless communications, fading is the variation of signal attenuation over variables like time, geographical position, and radio frequency. Fading is often modeled as a random process. In wireless systems, fading may either be due to multipa ...
is ''C'' = log
2(1 + ''h''
2 SNR), where ''h'' is the fading coefficient and SNR is a signal to noise ratio without fading. As ''C'' is
random
In common usage, randomness is the apparent or actual lack of definite pattern or predictability in information. A random sequence of events, symbols or steps often has no order and does not follow an intelligible pattern or combination. ...
, no constant rate is available. There may be a chance that information rate may go below to required threshold level. For slow fading channel, outage probability = P(''C'' < ''r'') = P(log
2(1 + ''h''
2 SNR) < ''r''), where ''r'' is the required threshold information rate.
See also
*
Shannon–Hartley theorem
In information theory, the Shannon–Hartley theorem tells the maximum rate at which information can be transmitted over a communications channel of a specified bandwidth in the presence of noise. It is an application of the noisy-channel coding ...
*
Fading channel
In wireless communications, fading is the variation of signal attenuation over variables like time, geographical position, and radio frequency. Fading is often modeled as a random process. In wireless systems, fading may either be due to multipa ...
References
Information theory
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