Joint Mode Selection and Resource Allocation for Device-to-Device Communications

TLDR

Device‑to‑device communications are proposed to boost spectrum and energy efficiency in future cellular systems. This work aims to jointly select modes, assign channels, and control power to maximize overall throughput while ensuring acceptable SNR for both D2D and cellular links. The authors model three D2D modes, decompose the problem into power control and joint mode/channel assignment subproblems, and propose low‑complexity load‑adaptive algorithms after noting the NP‑hardness of the optimal solution. Simulation results demonstrate that the proposed algorithms achieve proximity, hop, and reuse gains under varying network loads.

Abstract

Device-to-device (D2D) communications have been recently proposed as an effective way to increase both spectrum and energy efficiency for future cellular systems. In this paper, joint mode selection, channel assignment, and power control in D2D communications are addressed. We aim at maximizing the overall system throughput while guaranteeing the signal-to-noise-and-interference ratio of both D2D and cellular links. Three communication modes are considered for D2D users: cellular mode, dedicated mode, and reuse mode. The optimization problem could be decomposed into two subproblems: power control and joint mode selection and channel assignment. The joint mode selection and channel assignment problem is NP-hard, whose optimal solution can be found by the branch-and-bound method, but is very complicated. Therefore, we develop low-complexity algorithms according to the network load. Through comparing different algorithms under different network loads, proximity gain, hop gain, and reuse gain could be demonstrated in D2D communications.