Interference Neutralization for Non-Regenerative Two-Way Relaying Networks—Part I: Feasibility

In this paper, we study a nonregenerative two-way relaying (TWR) network with multiple repeaters and smart relays, where the smart relays use the amplify-and-forward relaying strategy. Interference-free transmission for such a network is realized using interference neutralization. The necessary and sufficient conditions for interference neutralization are characterized and verified. For an efficient system design, it turns out that one large relay equipped with as many antennas as possible is the best choice. Numerical simulations illustrate the feasibility region in terms of the number of relays and the number of relay antennas.