A resource allocation mechanism for enhancing spectral efficiency and throughput of multi-link D2D communications

In this paper, we consider downlink resource allocation of a cellular user to group of device-to-device (D2D) communication pair to enhance the overall system throughput and achieve higher spectral efficiency in mobile cloud. A mobile cloud can be defined as an opportunistic cooperative cluster of wireless devices in close proximity which are capable to communicate to other devices while preserving their connection to an overlay cellular access network (i.e., eNB), simultaneously. Thus this study considers D2D communications from a novel and wider perspective, assuming that multiple D2D communication links are simultaneously supported. We model, formulate and analyze the overall throughput of the mobile cloud as the function of distance between communication devices when the D2D pairs communicate in cellular, dedicated and reuse modes. In cellular and dedicated modes there is no severe intra-cell interference but for the reuse mode we propose an innovative and practical downlink resource allocation mechanism to coordinate the interferences and maximize the system sum-rate when several D2D pairs communicate by reusing the resources of a cellular user. In fact, the eNB as the centralized decision-maker selects a cellular user equipment (UE) and group of D2D pairs to communicate by reusing the downlink resources of the selected cellular UE while it guarantees the SINR at both the cellular and D2D receivers. Numerical results show that by exploiting the proposed mechanism we can achieve the aforementioned goals.