Energy Efficient Scheduling for Concurrent Transmission in Millimeter Wave WPANs

Directional antennas in millimeter wave (mmWave) communication networks enable spatial reuse by reducing interference during concurrent transmission. However, higher spatial multiplexing gain is realized at the cost of increased power consumption in antenna arrays. In this paper, we develop a multi-slot scheduling scheme based on mixed integer linear programming (MILP) for energy efficient scheduling in mmWave concurrent transmission. Energy efficiency (EE) is defined as the ratio of data rate achieved to the sum of circuit power consumption and transmit power. EE is achieved by the joint optimization of data rate and power consumption; while the optimum data rate request is calculated using a reinforced learning strategy, power consumption is minimized through antenna beamwidth control. We also prove that the energy efficient scheduling problem is NP-complete, and propose three novel low complexity energy efficient scheduling algorithms for mmWave networks - energy efficient directional medium access control (EEDMAC)-Naive, EEDMAC-Greedy, and EEDMAC-Double Greedy (DGreedy). The proposed multi-slot scheduling scheme is seen to outperform the existing protocol in terms of EE, and delay fairness. We further analyze the degradation in system performance due to antenna scanning range. The simulation results provide fresh insights into resource allocation and scheduling for mmWave directional communications.