A New Approach for D2D Assisted Multicast and Unicast Communications

Device-to-Device (D2D) communications are one of the main drivers of new wireless standards. D2D improves resource utilization, spectral efficiency, energy efficiency, cellular coverage of wireless networks, etc. In some D2D-assisted applications like online gaming, video streaming, and multimedia downloading, performances can be deteriorated, i.e., it is quite difficult to maintain energy-efficient services. Thus, in this paper, a new, energy-efficient, D2D-assisted, multicast/unicast downlink schemes are proposed. They can significantly increase the energy/spectral efficiency in the mentioned applications. Three different downlink scenarios are considered, where one radio access point (AP) transmits multicast or unicast traffic to a cluster of far users (FU), via one near user that behaves like relay station. The proposed schemes combine the novel multiple-input multiple-output (MIMO) techniques and the new spatial modulation (SM). This allows formation of the new, energy/spectral efficient, virtual SM-MIMO multicast/unicast channels between the AP and each FU. The simulation results show that energy/spectral efficiency can be increased without significant impairing of bit error rate performance.