Soft RS codes for half rate GSM channel

After the adoption in 1987 of the RPE-LTP coder as the 22.8 KBPS Pan European Mobile Speech Communication standard (full rate GSM or F-GSM), the next stage in the project is the development of a CODEC (source and channel) operating at 11.4 KBPS (half rate GSM or H-GSM). Many speech coding algorithms under evaluation are expected to meet the stringent quality specifications of H-GSM. However, during operation the channel perturbations are expected to be twice as bad for H-GSM as for F-GSM. Despite this, an error control scheme which uses less redundancy and provides performance which for the most part is superior to the scheme for F-GSM is expected. A high performance FEC scheme is presented which employs soft decoded Reed-Solomon (RS) codes on the H-GSM channel.