Capacity Enhancement Using Simultaneous Transmission in Device-to-Device Enabled Cellular Network

Device-to-Device (D2D) communication is a technology component for LTE- A. D2D would enable the direct communication of a device to another device using the cellular spectrum. D2D takes advantage of the physical proximity of communication devices, for example, high bit rate, low delays, low power consumption, etc. We propose a scheme that allows a D2D user to simultaneously transmit D2D and cellular signals in D2D-enabled cellular system. The proposed scheme has the advantage of frequency reuse. However, if D2D and cellular user equipments (UEs) transmit in the same radio resource blocks (RBs), co-channel interference will occur, which may decrease performance of cellular networks, and D2D will most likely fail. Therefore, we propose a precoding mechanism which uses the dirty paper coding (DPC) to remove the interference from cellular UE to D2D UE. We investigate different scheduling algorithms and dynamic power allocation mechanism to improve performance of the systems. By simulations, we show that the proposed mechanisms can improve performance of the entire communication systems.