On the Performance of Trellis Coded Modulation in a Concatenated Reed-Bolomon System

Concatenated systems combining the error correcting power of trellis codes and Reed-Solomon (RS) codes have been used to achieve error rates between 10-10 and 10-20 on satelite communications links [l]. The need for spectral efficiency has motivated consideration of of non-binary signalling with Ungerboeck [2,3] codes or the Pragmatic standard recently proposed by Viterbi [4], in place of quaternary signalling with rate 1/2 coding. In this paper we investigates the use of 8-PSK trellis-coded modulation (TCM) in a concatenated system using a (255,233) RS code. The use of the 8-PSK codes doubles the spectral efficiency with a performance cost of approximately 2 dB