Feasibility-Aware Partial Interference Alignment for Hybrid D2D and Cellular Communication Networks

Device-to-Device (D2D) communication has been a promising technology for the fifth generation (5G) wireless network owing to the higher throughput, less energy consumption, and lower latency. As the 5G network becomes denser, the interference in a hybrid D2D and cellular communication system becomes much severe and more difficult to deal with. In this paper, a novel feasibility aware partial interference alignment (FA-PIA) scheme is investigated. Partial IA has already been studied to manage severe interference for symmetric interference network or simple asymmetric network with limited users. In this paper, we consider an asymmetric interference network with an arbitrary number of D2D users transmitting concurrently. We aim to boost the degrees of freedom and achievable sum rate. To achieve this goal, a lower complexity three-step-based scheme is proposed. Specifically, the pressure transfer tree-based interference selection algorithm is first developed, which is to select the appropriate interference links to be aligned under the IA feasibility constraints. Then, the minimum interference leakage-based iterative partial IA scheme is given to mitigate the selected interference. At last, a constrained concave convex procedure-based iterative power optimization algorithm is provided to further manage the residual interference. Numerical results demonstrate that the proposed three-step-based FA-PIA scheme can significantly improve the achievable sum rate.