Joint channel-physical layer network coding in multi-way wireless relay systems

Multi-way relaying is a widely considered network configuration, where multiple communication nodes exchange their information via a single relay. In this configuration, a pairwise information exchange and a channel condition based node pair selection for simultaneous information transfer provide the best performance. For such schemes, the relationship between the minimum number of time slots required for complete information exchange among communication nodes and the number of communication nodes is derived. Furthermore, this paper proposes an improved joint channel decoding-network coding algorithm, which is to be employed at the relay node. In the proposed joint decoding algorithm, the soft information of the information bits is exchanged between the channel decoders corresponding to different node pairs transmitting simultaneously. We also propose three different schemes for soft information exchange between the different channel decoders. The proposed algorithm is highly scalable with respect to the number of communication nodes. Simulation results demonstrate that our proposed joint decoding algorithm offers improved error performance over the existing joint decoding algorithms for a three-way relay system under the three different information exchanging schemes. The simulation results verify that the performance of the proposed decoding algorithm increases with the number of overlapping information pairs