1 Power-management for base stations in smart grid environment

The overall contribution of cellular network operators to the entire human CO2 emissions is estimated at 2.5% in the U.S. [1]. Thereinto, about 60%− 80% originates from wireless base stations (BSs) [2]. As current cellular network architectures are designed to cope with peak load and degraded conditions, underutilization of them occurs most of the time. A recent study [3] shows that the average power-consumption of the traditional BS amounts to nearly 850 W, with only up to 40 W power consumed to transmit from the antennas and the rest wasted even during idle operation. This result indicates that there is a large room for power savings for today’s cellular networks. In this chapter, we consider the problem of power management for BSs with renewable power source in smart grid environment. In Section 1.2, we first provide an introduction of green wireless communications with the focus on two closely related research fields, i.e., renewable power source and smart grid. Then, we provide an overview on the power-management approaches for BS, which consists of two major directions, i.e., BS power control and smart BS operation. The former is achieved at the equipment level, while the latter can be realized at system/network level. Afterwards, we discuss some challenges and open issues with regard to power management for BS. In Section 1.3, we present the powerconsumption model for a BS. Specifically, the power consuming components are first introduced and analyzed. Moreover, we present two power-consumption models, one for macro BSs which contains a static power-consumption part only, and the other for micro BS which additionally consists of a dynamic powerconsumption part. The power-consumption models of macro BS and micro BS allow us to characterize, quantify, and compare different deployment strategies when realistic input parameters are available. In Section 1.4, we propose an adaptive power-management approach for wireless BS with a renewable power source in smart grid environment. While the main power supply of BS is from electrical grid, an alternative is from solar panel. An adaptive power-management approach is used to coordinate among electrical grid and the solar panel, which is energy-efficient and allows for greater penetration of variable renewable power sources in green communication system. With smart grid technology, the adaptive power management