دانلود رایگان مقاله Low-Carb: طرح عملی برای بهبود بهره وری انرژی در شبکه تلفن همراه

Abstract

Electricity cost constitutes a significant fraction of the total operations costs in a cellular network. We present Low-Carb, a practical scheme which reduces the power consumption in such networks. Low-Carb achieves this by coupling Base Transceiver Station (BTS) power savings with Call hand-off—two features widely available to cellular operators. Motivated by the observation that most callers are in the vicinity of multiple BTSs, Low-Carb allows calls to hand-off from one BTS to another so that BTS power savings can be applied to a maximal number of BTSs throughout the cellular network. The resulting reduction in energy consumption is shown to be governed by an optimization problem. We also provide optimal and heuristic solutions to this problem. We use BTS locations and traffic volume data from a large live GSM network to evaluate the power savings possible using our proposed approach. Our results indicate that performing coordinated call hand-off and BTS power-savings, a GSM 1800 network operator with about 7000 sites nation-wide can reduce annual electricity consumption by up to 35.36 MWh. This is at least 9.8% better than the energy savings achievable by using BTS power savings alone.

7. Conclusions

Base Transceiver Stations (BTSs) account for most of the energy consumption of cellular networks. Motivated by the lack of load-proportionality of BTS energy consumption, we proposed to combine two widely available features i.e., BTS power savings and call hand-offs. This combination allows calls to be handed-off from BTSs with high traffic load to neighboring BTSs to maximize the benefits of BTS power-saving. We formulated this problem as a binary integer program and showed that it is NP-Hard. We then proposed a polynomial-time heuristic algorithm. Using real network topology and traffic traces in a simulation study, we found that merely using BTS power saving in an urban setting can result in considerable energy savings. Moreover, our results also indicate that periodic call-shuffling between BTSs can further reduce energy consumption in existing large GSM networks.