Information about Code Rate
The code rate or information rate of a forward error correction (FEC) code, for example a convolutional code, states what portion of the total amount of information that is useful (non redundant). The code rate is typically a fractional number. If the code rate is k/n, for every k bits of useful information, the coder generates totally n bits of data, of which n-k are redundant.
If R is the gross bitrate or data signalling rate (inclusive of redundant error coding), the net bitrate (the useful bit rate exclusive of error coding) is ≤ R•k/n.
For example: The code rate of a convolutional code may typically be 1/2, 2/3, 3/4, 5/6, 7/8, etc, corresponding to that one redundant bit is inserted after every single, second, third, etc, bit. The code rate of the Reed Solomon block code denoted RS(204,188) is 188/204, corresponding to that 204 - 188 = 16 redundant bytes are added to each block of 188 byte of useful information.
A few error correction codes do not have a fixed code rate -- rateless erasure codes.
If R is the gross bitrate or data signalling rate (inclusive of redundant error coding), the net bitrate (the useful bit rate exclusive of error coding) is ≤ R•k/n.
For example: The code rate of a convolutional code may typically be 1/2, 2/3, 3/4, 5/6, 7/8, etc, corresponding to that one redundant bit is inserted after every single, second, third, etc, bit. The code rate of the Reed Solomon block code denoted RS(204,188) is 188/204, corresponding to that 204 - 188 = 16 redundant bytes are added to each block of 188 byte of useful information.
A few error correction codes do not have a fixed code rate -- rateless erasure codes.
See also
In telecommunication, forward error correction (FEC) is a system of error control for data transmission, whereby the sender adds redundant data to its messages, which allows the receiver to detect and correct errors (within some bound) without the need to ask the sender for
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In telecommunication, a convolutional code is a type of error-correcting code in which (a) each m-bit information symbol (each m-bit string) to be encoded is transformed into an n-bit symbol, where m/n is the code rate (
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In telecommunication, data signaling rate (DSR), also known as gross bit rate, is the aggregate rate at which data pass a point in the transmission path of a data transmission system.
Notes:
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Notes:
- The DSR is usually expressed in bits per second.
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In telecommunication, a convolutional code is a type of error-correcting code in which (a) each m-bit information symbol (each m-bit string) to be encoded is transformed into an n-bit symbol, where m/n is the code rate (
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In computer science, a block code is a type of channel coding. It adds redundancy to a message so that, at the receiver, one can decode with minimal (theoretically zero) errors, provided that the information rate (amount of transported information in bits per sec) would not exceed
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In computer science, fountain codes (also known as rateless erasure codes) are a class of erasure codes with the property that a potentially limitless sequence of encoding symbols can be generated from a given set of source symbols such that the original source symbols can
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Exformation is a term meaning explicitly discarded information. It was coined by Danish physicist Tor Nørretranders in his book The User Illusion published in English 1998.
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In 1943 Erwin Schrödinger used the concept of “negative entropy” in his popular-science book What is life?. Later, Léon Brillouin shortened the expression to a single word, negentropy.
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