Interplay between cooperative device-to-device communications and green LTE cellular networks

Abstract

Traditional efforts for saving energy in cellular networks focus on reducing the transmit powers of base stations (BSs) and mobile devices. However, when a BS is in its working mode, studies show that more than 50% of the energy consumed is due to circuit processing, air conditioning, and other factors [1]. In addition to the growing awareness of energy-efficient wireless networks and their environmental benefits, electricity bills have become a significant cost factor for mobile operators [2]. This trend in reducing energy consumption and ensuring green wireless networks is supported by political and national initiatives, which are beginning to put requirements on lowering the CO2 emissions. For example, the European Commission research project EARTH concentrates on energy efficiency in radio access networks with the goal of finding solutions and concepts that can reduce energy consumption of mobile broadband systems by 50% [3]. An effective approach to save energy in wireless networks is to completely turn off selected BSs when the traffic load becomes light (e.g., see Refs. [4-7]).