Interference Alignment in Device-to-Device LAN Underlaying Cellular Networks

This paper studies a device-to-device (D2D) LAN underlaying a cellular uplink, where multiple D2D users (DUs) intend to communicate with a D2D receiver. Two interference alignment (IA) based D2D communication schemes are proposed to manage the interference between two networks. The first scheme is referred to as “interference-free” IA scheme. In this scheme, the interference signals from DUs are designed to be aligned in the orthogonal space of cellular links at the evolved NodeB (eNB), so that the links of cellular users (CUs) are completely free from interference. The second scheme is referred to as “interferencelimiting” IA scheme. In this scheme, the DUs´ signals are allowed to occupy some links of CUs, but the peak interference power on each of the “interfered” links is controlled under a certain threshold γ. The “interference-limiting” IA scheme is most efficient when there are a large number of DUs as the scheme can take advantage of multiuser diversity. Performance analysis shows that based on the proposed schemes, the interference generated on the cellular links is eliminated or well controlled, while the quality of service of the D2D LAN can also be guaranteed.