Realization of TDD Two-way Multi-hop Relay Network with MIMO Network Coding

This paper develops the first prototype hardware for TDD two-way multi-hop relay network with MIMO network coding. Since conventional wireless multi-hop relay networks have a drawback of low data rate, TDD two-way multi-hop relay networks have been studied as a solution to realize high data rate recently. In the networks, forward and backward streams are spatially multiplexed by using interference cancellation techniques such as MIMO beamforming or MIMO network coding. In this paper, demonstration system for TDD two-way multihop relay network with MIMO network coding (called 2-way relay network hereafter) is developed by using the prototype hardwares. In the demonstration system, each transmitter and receiver performs network coded broadcast and MIMO multiple access respectively. By using the demonstration system, network throughput is measured in a real indoor environment to prove the realization and effectiveness of the 2-way relay network. The network throughput of the 2-way relay network is about twice as large as that of the simple TDD one-way multi-hop relay network (1-way relay network), and higher than that of the direct link at all average end-to-end SNRs. From the result, the realization and effectiveness of the 2-way relay network is proved in the real indoor environment.