Serial concatenated trellis coded modulation with inner rate-1 accumulate code

In this paper we propose a serial concatenated trellis coded modulation system using an inner accumulate code and a Gray-labeled signal constellation. The simple inner code and the Gray labeling allow us to extend to higher-order constellations the coding theorems of Divsalar et al., (1998), and Pfister et al., (2000), stating that when the signal-to-noise ratio (SNR) exceeds a certain, system-specific threshold, the word error probability goes to zero as the blocklength goes to infinity. We also evaluate the performance for finite blocklengths using an improved union bound. Despite the simple inner code, the simulated performance in AWGN and Rayleigh fading is equal to the performance of more complex systems suggested in the literature.