Energy-Efficient Full-Duplex Concurrent Scheduling Based on Contention Graph in mmWave Backhaul Networks

In the fifth generation (5G) era, dense deployment of small cells and full-duplex (FD) technology applications are two key features of millimeter-wave (mmWave) wireless communication systems, which offer the opportunity to meet the explosive growth of data service requirements. It is the beamforming and advances in analog as well as digital self-interference (SI) cancellation schemes that improve the network capacity in mmWave wireless backhaul networks. To achieve power saving and further network performance optimization, we propose a FD concurrent transmission mechanism employed in a mmWave backhaul network. Contention graph is constructed in consideration of multi-user interference (MUI), SI, and FD transmission constraints. Then flow-grouping and power control algorithms are proposed based on the contention graph. We evaluate the performance of the proposed algorithm in terms of energy consumption, achievable network throughput, and energy efficiency. The impact of the interference threshold on the system performance is also investigated when the distribution of base stations (BSs), traffic loads, and maximum transmission powers change. Simulation results illustrate that with proper SI cancellation and interference threshold, the proposed concurrent mechanism outperforms time-division multiple access (TDMA), half-duplex (HD) concurrent transmission, and FD concurrent transmission without power control.