“…Although ZF‐based transmit precoding and receive equalisation provide sub‐optimal performance, they offer least system complexity. In [30–32], the ZF‐based schemes have been studied for basic two‐way AF relay systems. So far, most of the works have investigated MIMO‐based D2D communications either in one‐way [16, 24, 25] and/or in underlay scenario [26, 27].…”