Robust null-space based interference avoiding scheme for D2D communication underlaying cellular networks

In this paper, we design a null-space based robust interference avoiding strategy for the Device-to-Device (D2D) communication underlaying network. Thanks to the coordination between D2D user and the regular user, the interfering channel state information (CSI) among the base station (BS), cellular user equipment (CUE) and the D2D user equipments (DUEs) can be estimated from the training approach. Then, the null-space based transmit and receive beamformings are designed at appropriate terminals to mitigate the interference caused in the future data transmission. To make the design practical, we also characterize the null-space uncertainty that is resulted from the imperfect channel estimation. Moreover, we derive the optimal transmission strategy that can achieve the best training-throughput tradeoff. Simulation results are provided to corroborate the proposed studies.