Performance Comparison of PNC for different Modulation Techniques with Oversampling Digital Filter at the Rela

In a wireless transmission network, relay node or intermediate nodes play a very important role. Thus, the use of relay transmission offers significant performance benefits, including being able to achieve spatial diversity through node cooperation and extending coverage without requiring large transmitter powers. In this paper, we consider a Physical-layer Network Coding (PNC) scheme for a two-way wireless system where two source nodes, A and B, communicate with each other through the aid of relay node using an Amplify and Forward(AF) protocol where the relay oversamples the received signal and subsequently filters before amplification. This study makes an elaborate comparison of performance of PNC for different modulation techniques like Quadrature Phase Shift Keying (QPSK), 8-PSK and 16-quadrature amplitude modulation (16-QAM) and the corresponding improvement in the performance in all the three modulation techniques by oversampled filter at the relay. The simulation results showed that QPSK performs better in terms of sum bit error rate (Sum-BER) and Maximum sum-rate. Also the simulation results indicate that the oversampled digital filter at the relay enhances the Max sum-rate in all the three modulation techniques. Index Terms – PNC, Two-way relay channels, Amplify-Forward protocol, Sum-BER, Maximum sum-rate.