On the Error Floor Performance of SCTCM Systems with Non-Recursive Inner Codes

It has previously been shown that serially concatenated trellis coded modulation (SCTCM) with a non-recursive inner convolutional code can achieve convergence close to capacity. In this paper, we supplement the analysis by comparing recursive and non-recursive inner codes with respect to the bit error rate (BER) of the error floor region. We show that the high error floor, commonly attributed to serially concatenated codes using a non-recursive inner code, can be reduced significantly through careful code design. The considered system is iteratively decoded SCTCM with an outer single parity check (SPC) code and a two-state rate 3/4 inner convolutional code whose output is mapped to 8PSK. Simulation results are shown for the additive white Gaussian noise (AWGN) channel.