Nonbinary network coded cooperation with bit-interleaved coded modulation

Nonbinary network coding (NBNC) is an efficient approach to exploit the space diversity and improve the information throughput in a cooperative communication scenario. It provides substantial performance gains over those cooperative schemes without network coding (NC) or only with binary network coding (BNC). However, since the nonbinary network coded information is defined in a larger finite field, cooperative communications with NBNC will result in the loss of spectral efficiency and the increased energy consumption. This paper proposes a spectrally efficient nonbinary network coded cooperative scheme by employing the bit-interleaved coded modulation (BICM) and iterative decoding, i.e., BICM-ID, to combat spectrum and energy efficiency loss while maintaining a good communication performance. Spectral efficiency of a cooperative user is analyzed and it is utilized as a reference to compare with other existing cooperative schemes. Our simulation results demonstrate the proposed scheme achieves significant performance improvements over various benchmark schemes without further loss of spectrum efficiency and energy consumption.