Performance of trellis-coded 8-PSK with outer Reed-Solomon code over a nonlinear satellite link

A new modem/codec with improved bandwidth efficiency which is considered to be used for future INTELSAT IDR/IBS services is described and analysed. The codec uses concatenated coding with interleaving where the inner code consists of trellis-coded 8-PSK modulation (TCM) and the outer code is a high rate Reed-Solomon code over GF(2⁸). Two TCM-codes of rate 2/3 with 64 states, namely a systematic Ungerboeck- and the so-called pragmatic code, are investigated and compared. The system is analysed mainly by means of computer simulations where the following effects and impairments have been considered: square-root Nyquist filtering with raised cosine roll-off at transmitter and receiver side, additive white Gaussian noise (AWGN) and phase noise of receiver input signal, nonlinear effects due to AM/AM and AM/PM-conversion of the satellite high power amplifier (HPA) for single-carrier and multi-carrier-per-transponder transmission, and co-channel and adjacent channel interferences. For the linear AWGN channel a coding gain of 5 dB is achieved at BER=10^-5 with an RS(216,200) outer code and a small interleaver of depth 6