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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Code rate | 1/1 | https://en.wikipedia.org/wiki/Code_rate | reference | science, encyclopedia | 2026-05-05T11:31:47.594641+00:00 | kb-cron |
In telecommunication and information theory, the code rate (or information rate) of a forward error correction code is the proportion of the data-stream that is useful (non-redundant). That is, if the code rate is
k
/
n
{\displaystyle k/n}
, for every k bits of useful information, the coder generates a total of n bits of data, of which
n
−
k
{\displaystyle n-k}
are redundant. If R is the gross bit rate or data signalling rate (inclusive of redundant error coding), the net bit rate (the useful bit rate exclusive of error correction codes) is
≤
R
⋅
k
/
n
{\displaystyle \leq R\cdot k/n}
. For example: The code rate of a convolutional code will typically be 1⁄2, 2⁄3, 3⁄4, 5⁄6, 7⁄8, etc., corresponding to one redundant bit inserted after every single, second, third, etc., bit. The code rate of the octet oriented Reed Solomon block code denoted RS(204,188) is 188/204, meaning that 204 − 188 = 16 redundant octets (or bytes) are added to each block of 188 octets of useful information. A few error correction codes do not have a fixed code rate—rateless erasure codes. Note that bit/s is a more widespread unit of measurement for the information rate, implying that it is synonymous with net bit rate or useful bit rate exclusive of error-correction codes.
== See also == Entropy rate Information rate Punctured code
== References ==