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, the authors supplement the analysis by comparing recursive and non-recursive inner codes with respect to the Bit Error Rate (BER) of the error floor region. They 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.