Energy Efficient User Association and Power Allocation in Millimeter Wave Based Ultra Dense Networks with Energy Harvesting Base Stations

摘要

Millimeter wave (mmWave) communication technologies have recently emerged asan attractive solution to meet the exponentially increasing demand on mobiledata traffic. Moreover, ultra dense networks (UDNs) combined with mmWavetechnology are expected to increase both energy efficiency and spectralefficiency. In this paper, user association and power allocation in mmWavebased UDNs is considered with attention to load balance constraints, energyharvesting by base stations, user quality of service requirements, energyefficiency, and cross-tier interference limits. The joint user association andpower optimization problem is modeled as a mixed-integer programming problem,which is then transformed into a convex optimization problem by relaxing theuser association indicator and solved by Lagrangian dual decomposition. Aniterative gradient user association and power allocation algorithm is proposedand shown to converge rapidly to an optimal point. The complexity of theproposed algorithm is analyzed and the effectiveness of the proposed schemecompared with existing methods is verified by simulations.