Joint mode selection and power control for D2D underlaid cellular networks

Abstract

Device-to-Device (D2D) communication is a new paradigm proposed in cellular networks, which promises several benefits to the network providers as well as end users. Firstly, it improves spectral efficiency (SE) of cellular networks by re-using the same frequency resources occupied by cellular users. In fact, mobile users cellular networks use high data rate services (e.g., video sharing, gaming, proximity aware social networking etc.), in which they could potentially be in range for direct communications (i.e., D2D). Secondly, D2D can enhance energy efficiency (EE), since the mobile terminals use less transmission power when communicating directly between each other. Thirdly, D2D communication can also reduce communication delay and increase network throughput, due to its short distance communication. This paper investigates the future challenges in order to improve the network throughput by proposing a joint mode selection (MS) and centralized power control (PC), which maximizes the sum rate of D2D links. To keep the interference under control, coverage probabilities are studied in this paper for both cellular and D2D users, while a signal-to-interference-plus-noise ratio (SINR) threshold is maintained for more than one CUE. Based on the latter assumption, this paper provides two sufficient conditions to ensure the existence of the Pareto optimal power, that should be verified by both Cellular User Equipment (CUE) and D2D User Equipment (DUE) during the MS process. The mathematical expressions of these two sufficient conditions are proved. Then, the PC approach is deduced based on two derived sufficient conditions. Two joint MS and PC algorithms are proposed in this paper and compared in terms of coverage probability and total power consumption with a conventional algorithm for both CUE and DUE.