Trellis- and Network-Coded Modulation for Decode-and-Forward Two-Way Relaying Over Time-Varying Channels

We present a bandwidth-efficient joint channel coding-modulation scheme conceived for the broadcast channel of decode-and-forward (DF) two-way relaying (TWR), where trellis-coded modulation (TCM) is intrinsically amalgamated with network-coded modulation (NCM) for achieving both a channel coding gain and a high throughput. We conceive a low-complexity receiver algorithm for our joint TC-NCM scheme, which applies decoding and demodulation simultaneously, without the need to first demodulate the signal before decoding, as in the traditional solutions. As a further contribution, the TC-NCM scheme is intrinsically amalgamated with adaptive transceiver techniques. We then further investigate the performance of our near-instantaneously adaptive discrete-rate TC-NC-quadrature-amplitude modulation/phase-shift keying (QAM-PSK) scheme. Both simulation results and numerical analysis are presented, which are compared with the performance of traditional NCM schemes. The results show that our scheme not only increases the achievable transmission rate but improves the reliability as well, yet it is of modest complexity.