# Reed-Solomon decoder,

Reed-Solomon errors only

### Product codes: CMS0013, CMS0007

A Reed-Solomon Codec core for use in many wireless applications including 802.16 and DVB-T/DVB-C/DVB-S.

The Reed-Solomon code has message length K and codeword length N. The symbols for the code are integers between 0 and 2^{M}-1, which represent elements of the finite field GF(2^{M}). The difference N - K must be an even integer. An (N, K) Reed-Solomon code can correct up to T=(N-K)/2 byte (symbol) errors in each codeword.

Commsonic offers two RS Codec products - a full-featured Errors and Erasures Codec(CMS0013) and an Errors-Only Codec(CMS0007).

The Errors and Erasures Codec is intended for applications such as IEEE802.16 that require code puncturing (dynamic control over the number of parity symbols that are used by the code) or with systems such as DVB-MPE that use erased symbols (symbols where the decode confidence is low).

The Errors-Only Codec does not support code puncturing or erased symbols and is optimized to provide a compact design for application that require a fixed number of parity symbols such as MPEG/DVB-T/DVB-S/DVB-C.

A typical application of this core would be for the 802.16 wireless MAN standard where the options would be set as follows:

N=255, K=239, T=8, GF(256) i.e. M=8.

G(x)=(x-α^{0})(x-α^{1}) … (x-α^{2T-1}).

α=2, J0=0.

P(x) = x^{8} + x^{4} + x^{3} + x^{2} + 1.

A RS encoder is also available.