Orthogonal projection based asymmetric multi-way relaying with antenna subset selection

An asymmetric multi-way relay communication scheme using orthogonal projection and analogue network coding is proposed. The scheme is designed for the wireless sensor network, where one sink node (SN) exchanges information with multiple user nodes via a relay station and both the SN and user nodes have low complexity structures. It has been observed that the minimal number of the relay antennas can be smaller than that of the total data streams. Moreover, when the number of the relay antennas is larger than the minimum, a paired throughput based max-min criterion with low computational complexity is developed to select the optimal relay antenna subset and guarantee full diversity gain. The numerical results demonstrate the high performance of the proposed communication scheme and antenna subset selection criterion.