Towards Energy-Efficient Underlaid Device-to-Device Communications: A Joint Resource Management Approach

Abstract

With increasing demands of green wireless communications, energy-efficient device-to-device (D2D) communications have attracted increasing attention. However, with resource sharing in an underlying manner, the system performance may be greatly degraded by the co-channel interference. For friendly coexistence of D2D and cellular communications, in this paper, we propose a joint resource management scheme where direct mode, two-hop mode, and cooperative mode are supported. Specifically, the joint resource management is formulated as a three-dimensional (3-D) power-mode-channel problem that maximizes the overall energy efficiency (EE) of D2D communications while guaranteeing the quality of service (QoS) of both D2D and cellular communications. To solve the formulated problem, the 3-D problem is decoupled by employing the orthogonality of different D2D links and the uniqueness of transmission mode for one D2D pair. Besides, considering that the introduction of cooperative mode increases the complexity of 3-D resource allocation algorithm, on the basis of the optimal scheme, we further propose a sub-optimal scheme to reduce the average time complexity. The simulation results verify the viability of the proposed schemes and reveal the impacts of system parameters such as the QoS, the distance between D2D source and destination, the location of the relay, and the number of D2D pairs on the EE of D2D systems.

Keywords

• Device-to-device communications
• energy efficiency
• power allocation
• mode selection
• channel assignment