Orthogonal MIMO precoding schemes for device-to-device communication in LTE networks

Direct communications between mobile terminals, also known as Device-to-Device (D2D) communications, is expected to be one of the key features supported by upcoming mobile networks. The D2D communication uses resources of the underlying mobile network which however results in mutual interference between the D2D and base station-to-terminal links. To reduce the mutual interference of these links, we propose a novel orthogonal Multiple Input Multiple Output (MIMO) precoding approach where the orthogonal precoding matrices are assigned to the D2D and base station-to-terminal communication links. The expression for outage probability of the proposed method is also presented in this paper. Numerical results show that our proposition achieves an enhancement of capacity gain in comparison with conventional precoding matrix allocation method and reduction in outage probability in comparison with conventional interference cancellation technique.