BER Analysis of RIS Assisted Multicast Communications with Network Coding

In this paper, Reconfigurable Intelligent Surface (RIS) assisted dual-hop multicast wireless communication network is proposed with two source nodes and two destination nodes. RIS boosts received signal strength through an intelligent software-controlled array of discrete phase-shifting metamaterials. The multicast communication from the source nodes is enabled using a Decode and Forward (DF) relay node. In the relay node, the Physical Layer Network Coding (PLNC) concept is applied and the PLNC symbol is transmitted to the destination nodes. The joint RIS-Multicast channels between source nodes and the relay node are modeled as the sum of two scaled non-central Chi-Square distributions. Analytical expressions are derived for Bit Error Rate (BER) at relay node and destination nodes using Moment Generating Function (MGF) approach and the results are validated using Monte-Carlo simulations. It is observed that the BER performance of the proposed RIS assisted network is a lot better than the conventional non-RIS channels links.