Zero-Forcing based Multiuser Two-Way AF Relay Network under Relay Power Constraint

A two-way amplify-and-forward (AF) wireless relay network consisting of 2M sources with only a single antenna per source and one relay with multiple N antennas is studied with a self-interference cancelation process at the 2M destinations in this paper. All sources act as both sources and destinations. The closed form of the relay amplifying matrix is optimized under the relay transmit power constraint based on the zero-forcing (ZF) criterion. Additionally, the no-power constraint case of the ZF relaying scheme is investigated, as well. Furthermore, the transmit power consumption at the relay is studied during data transmission. The proposed system performance is evaluated in relation to the average bit error rate (BER) by computer simulation. Finally, numerical results show that the system performance improves as either N or input SNR increases.