Channel Precoding for Compute and Forward Relaying in Two Way Relay Network Model

Physical layer Network Coding (PNC) is a promising strategy to improve the spectral efficiency in a relay-based wireless transmission. This paper employs lattice-based channel coding at the source nodes for better performance during Multiple Access Channel (MAC) phase transmission. The achievable transmission rate in various PNC relaying such as Decode and Forward (DF), Amplify and Forward (AF), and Compute and Forward (CF) for the Two Way Relay Network model (TWRN) is derived and simulated through MATLAB software and analyzed. The analysis shows that the rate performance of CF relaying outperforms other relaying techniques in the Additive White Gaussian Noise (AWGN) channel, but it degrades for the Rayleigh fading channel. To mitigate the fading effects, channel aware precoding technique is employed at source nodes, Bit Error Rate (BER) and Symbol Error Rate (SER) performance are analyzed for CF relaying, and Monte Carlo simulations are used to demonstrate the theoretical results. Channel precoding performance of CF relaying is compared with DF relaying.