Abstract-Using energy generated with fossil fuel causes global warming due to the greenhouse effect, which threatens our environment. One of the challenges for New Generation Networks (NGN) is then the reduction of energy consumption, in particular at the BSs (Base Stations) which use about 85% of the total network energy. We contribute to the research with a mathematical model that calculates the total power consumption of a BS and enlightens the way to minimize it. First, we analyze the power consumed at every different component of the BS. Second, based on the cost incurred in turning off the BS's power amplifiers, we show how to decide whether it is convenient to keep the BS idle during those intervals in which no traffic has to be sent, or to turn off the amplifiers. Our model is evaluated by means of numerical examples, and shows that interesting power gain can be obtained under a large spectrum of load conditions.

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The IEEE Standard 802.3az, namely Energy Efficient Ethernet (EEE), has been recently introduced to reduce the power consumed in LANs. Since then, researchers have proposed various traffic shaping techniques to leverage EEE in order to boost power saving. In particular, packet coalescing is a promising mechanism which can be used on top of EEE to tradeoff power saving and packet delay. In this paper, we analyze the interesting and special case of 1000Base-T EEE links, in which power saving operations are triggered only when links are inactive in both transmission directions. We are the first to provide an analytical model for EEE 1000Base-T which accounts for the bidirectional nature of LAN traffic. Our model allows to compute the power saving achieved by EEE, with and without packet coalescing, by using a few significant traffic descriptors. Furthermore, we use real traffic traces to investigate on the performance of static as well as dynamic coalescing schemes. Our results show that dynamic coalescing does not significantly outperform static coalescing in terms of power save and delay.