A Downlink Precoding-based Interference Mitigation Scheme in Device-to-Device MIMO Systems

To mitigate the strong interference from the Base Station (BS) to Device-to-Device (D2D) receivers when the downlink resource is shared by the D2D and cellular users, a novel null-space based precoding scheme is proposed. The proposed scheme takes into account the interference mitigation for D2D users when designing the downlink precoders of the BS. It allows the transmitted signal of BS to aim at the scheduled cellular user while lying in the interference-free subspace of the BS-D2D channel, so as to avoid the interference to the D2D receivers. To make the design more practical, the performance of the proposed scheme under imperfect channel estimations is further analyzed. Simulation results show that substantial gains in D2D throughput can be obtained by using the proposed precoding scheme, but such gain is largely dependent on the accurate channel state information of the BS to D2D receiver.