The performance of network coding at the physical layer with imperfect self-information removal

Network capacity for bidirectional communication between pairs of wireless end users assisted by a relay terminal can be improved by network coding at the physical layer (PNC). Narrowband analog network coding (ANC) was introduced as a simpler implementation of PNC in a flat (i.e., frequency-nonselective fading) channel. Recently, broadband ANC has been studied for communication over a frequency-selective fading channel. In ANC, the end user removes its own information from the received signal before detecting the data of the other user. Clearly, the network performance of ANC scheme depends on the self-information removal at the destination terminal. In this paper, we discuss the impact of imperfect self-information removal on the performance of broadband ANC in terms of the bit error rate (BER) and achievable throughput in a frequency-selective fading channel. The theoretical minimum mean square error (MMSE) equalization weight for ANC based on single carrier with frequency domain equalization (SC-FDE) radio access is derived by taking into account the self-interference. We have used analysis and computer simulation to evaluate how the imperfect removal of self-information influences the achievable BER and throughput.