Superimposed adaptive network coded cooperation for wireless sensor networks

In this paper, we propose a bandwidth efficient distributed network code, termed superimposed adaptive network coded cooperation (SANCC), for a network consisting of M users sending different information packets to a common destination through independent block fading channels. Different from conventional cooperative communications with half-duplex constraint, our proposed approach does not reduce the bandwidth efficiency with the aid of high order modulation while its encoding process is still performed by simple XOR operation similar to the conventional adaptive network coded cooperation (ANCC). In order to exploit the structure of the proposed approach, effective mapping and corresponding decoding are investigated. We further propose a modified encoding for SANCC to improve the inherent error floor behavior and analyze its performance based on extrinsic information transfer (EXIT) chart. Finally, the effectiveness of our proposed approach is confirmed via computer simulations.