Interference-Aware Resource-Sharing Scheme for Multiple D2D Group Communications Underlaying Cellular Networks

Device-to-device (D2D) communications underlaying cellular networks have the potential to improve spectrum efficiency and link capacity by allowing nearby devices to communicate directly with each other on the licensed frequency bands. However, co-channel interference between cellular users (CUEs) and D2D pairs and co-channel interference among D2D pairs are major issues to be solved. In this paper, we propose an efficient interference-aware frequency resource-sharing scheme for multiple D2D groups that can efficiently maximize system throughput by considering grouping method, adaptive antenna arrays, and application of interference alignment (IA) for the D2D communications. Using a grouping method, nearby D2D pairs can form D2D groups for the convenience of implementing IA to cancel the interference among the D2D pairs in the group. Interference from the eNB to D2D pairs is reduced by the use of beamforming at the eNB. Furthermore, a greater distance between the D2D pairs and CUEs assists in reducing the interference between them. System-level simulation results confirm that the proposed scheme improves cell throughput compared with conventional distance sharing and random sharing schemes by 8.3 and 23.8 %, respectively. The proposed scheme also demonstrates high cell throughput gain in comparison to the scenario of "without IA".