Burst error

In telecommunication, a burst error or error burst is a contiguous sequence of symbols, received over a data transmission channel, such that the first and last symbols are in error and there exists no contiguous subsequence of m correctly received symbols within the error burst.[1]

The integer parameter m is referred to as the guard band of the error burst. The last symbol in a burst and the first symbol in the following burst are accordingly separated by m correct bits or more. The parameter m should be specified when describing an error burst. For example, imagine sending a packet containing all of the letters of the alphabet, A through Z. If the recipient's computer "opens" the packet and finds that the first letter in the sequence is "Q" and the last letter in the sequence is "R," that is a burst error. The "burst" of data in the packet is corrupt.

Although in the example the first and last letters are defined as corrupt, that does not mean that every letter within the packet is damaged. Imagine that every other letter is as it should be; only position one, "A," and position 26, "Z," have been damaged. The number of correct bits of information between the damaged ends is called the guard band. In this case, the guard band would be 24, because there are 24 correct letters separating the two damaged ones.

Channel model

The Gilbert–Elliott model is a simple channel model introduced by Edgar Gilbert[2] and E. O. Elliott [3] widely used for describing burst error patterns in transmission channels, that enables simulations of the digital error performance of communications links. It is based on a Markov chain with two states G (for good or gap) and B (for bad or burst). In state G the probability of transmitting a bit correctly is k and in state B it is h. Usually,[4] it is assumed that k = 1. Gilbert provided equations for deriving the other three parameters (G and B state transition probabilities and h) from a given success/failure sequence. In his example, the sequence was too short to correctly find h (a negative probability was found) and so Gilbert assumed that h = 0.5.

References

  1. ↑ Federal Standard 1037C
  2. ↑ Gilbert, E. N. (1960), "Capacity of a burst-noise channel", Bell System Technical Journal 39: 1253–1265, doi:10.1002/j.1538-7305.1960.tb03959.x.
  3. ↑ Elliott, E. O. (1963), "Estimates of error rates for codes on burst-noise channels", Bell System Technical Journal 42: 1977–1997, doi:10.1002/j.1538-7305.1963.tb00955.x.
  4. ↑ Lemmon, J.J.: Wireless link statistical bit error model. US National Telecommunications and Information Administration (NTIA) Report 02-394 (2002)

External links

 This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C" (in support of MIL-STD-188).


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