Energy efficient D2D communications in dynamic TDD systems

TL;DR

This paper explores how integrating device-to-device communication with dynamic TDD can significantly improve energy efficiency and spectrum utilization in future cellular networks, benefiting device battery life and system sustainability.

Contribution

It introduces joint optimization algorithms for mode selection, transmission period, and power allocation in D2D-enabled dynamic TDD systems, addressing NP-hard problems with efficient solutions and heuristics.

Findings

Significant energy savings demonstrated in simulations.

Enhanced spectrum efficiency with D2D and flexible TDD.

Heuristic algorithms provide near-optimal solutions.

Abstract

Network-assisted device-to-device communication is a promising technology for improving the performance of proximity-based services. This paper demonstrates how the integration of device-to-device communications and dynamic time-division duplex can improve the energy efficiency of future cellular networks, leading to a greener system operation and a prolonged battery lifetime of mobile devices. We jointly optimize the mode selection, transmission period and power allocation to minimize the energy consumption (from both a system and a device perspective) while satisfying a certain rate requirement. The radio resource management problems are formulated as mixed-integer nonlinear programming problems. Although they are known to be NP-hard in general, we exploit the problem structure to design efficient algorithms that optimally solve several problem cases. For the remaining cases, a heuristic algorithm that computes near-optimal solutions while respecting practical constraints on execution times and signaling overhead is also proposed. Simulation results confirm that the combination of device-to-device and flexible time-division-duplex technologies can significantly enhance spectrum and energy-efficiency of next generation cellular systems.