Performance Analysis of Zero-Forcing for Two-Way MIMO AF Relay Networks

Transmit/receive zero-forcing (ZF) is studied for multiple-input multiple-output (MIMO) amplify-and-forward (AF) two-way relay networks (TWRNs). Specifically, two sources employ transmit and receive ZF during two consecutive time-slots for transmission and reception, respectively, while the relay performs analog network coding. Each source then requires only the instantaneous respective source-to-relay channel knowledge, and hence, the complexity of practical implementation is significantly reduced. The performance of this system set-up is studied by deriving the upper and lower bounds of the overall outage probability, their high signal-to-noise ratio approximations and diversity order. To obtain valuable insights into practical MIMO TWRN implementation, the diversity-multiplexing trade-off is also quantified.