Energy-Aware Base Stations: The Effect of Planning, Management, and Femto Layers

We compare the performance of three base station management schemes on three different network topologies. In addition, we explore the effect of offloading traffic to heterogeneous femtocell layer upon energy savings taking into account the increase of base station switch-off time intervals. Fairness between mobile operator and femtocell owners is maintained since current femtocell technologies present flat power consumption curves with respect to served traffic. We model two different user-to-femtocell association rules in order to capture realistic and maximum gains from the heterogeneous network. To provide accurate findings and a holistic overview of the techniques, we explore a real urban district where channel estimations and power control are modeled using deterministic algorithms. Finally, we explore energy efficiency metrics that capture savings in the mobile network operator, the required watts per user and watts per bitrate. It is found that the newly established pseudo distributed management scheme is the most preferable solution for practical implementations and together with the femotcell layer the network can handle dynamic load control that is regarded as the basic element of future demand response programs

Energy-efficient planning and management of cellular networks

We study base stations energy-efficient management algorithms in a cellular access network taking into account different planning strategies. To provide energy savings, sleep modes are adopted at the Base Stations (BSs). We propose two switch-off strategies that are based either on the cell load or the BS coverage overlap. Our results show that energy savings between 10% and 30% can be achieved also for the deployment already planned to be energy-efficient, while even higher savings are achievable with the other deployments. Moreover, we find that both the proposed switch-off strategies obtain similar results, suggesting that the order at which the BSs are switched-off, and the set of BSs selected to be switched off, do not change significantly the average estimation of potential energy savings. Furthermore, on a realistic case study, comparisons are made between the results obtained by using deterministic channel estimation models and empirical formulations. © 2012 IEEE

The TREND meter: Monitoring the energy consumption of networked devices

In this paper the authors detail the TREND meter, a tool for monitoring the power and the utilization of networked devices. Their solution is based on standard measurements and data export methods. The TREND meter provides graphed energy consumption and load information of each measured device. After detailing the TREND meter architecture, the authors reported the main results that they had obtained by collecting measurements from a variety of devices. Their solution represents the starting point towards a more complex tool able to monitor a network infrastructure and to trigger energy saving techniques when traffic conditions change. Copyright \ua9 2013, IGI Global

Final phase-resolving Boussinesq-type models (D42)

The design of structures to be built in the nearshore region generally involves the evaluation of different possible layouts, under the effects of local wave and cunents conditions, with the aim of minimizing costs and maximizing the desired results. In particular the design of lowcrested structures involves optimisation of several parameters, which influence both the position, and the shape of the structures. The possible layout of the structures to be designed can be tested experimentally in wave tanks and wave flumes using adequate scale models. An alternative and attractive procedure is to employ suitable numerical and mathematical models. In principle, a very advanced numerical model, able to conectly simulate all the nearshore phenomena (turbulence, waves, currents, sediment transport, etc.) could be equivalent or even superior to a physical model. In practice, the numerical models currently employed in engineering activities, use several assumptions and simplifications: the phenomena that can be simulated strictly depend on the governing equations solved by the model. Indeed, the great advantage of numerical and mathematica! models is that their application is usually much less expensive than physical ones: it is certainly more economie to modify a computer file describing the bathymetry of the area under investigation than rebuild a physical model layout. This report is structured into two discrete sections, the first one contributed by AUTh and the second one by UR3. In the first section a 2DH higher-order Boussinesq-type model combined with a porous flow model, developed tor simulating flow around porous submerged structures is presented. On the other hand, in the second section enhancements on the applicability of Boussinesq-type equations (BTE) into the surf and swash zone are described.Delo

An overview of energy-efficient base station management techniques

Cellular networks have been traditionally dimensioned to fulfill the desired quality of service (QoS) requirements at all times, and consequently their deployment has been planned to meet the expected peak of the user demand. However, with the user demand recently increasing at exponential pace, concerns about the cellular networks energy consumption have been raised. In response, energy-efficient resource management schemes have been proposed, which take into account energy consumption, and control how much of the network infrastructure is actually needed at different times, and how much can be temporarily powered off to cut energy consumption. Since most of the energy consumed in cellular networks is used by base stations (BSs), algorithms for managing BSs seem to be the most urgent development to achieve energy-efficient operation. This paper provides a quick overview of the BS management techniques that were recently proposed for cellular networks. In addition, an outlook on real implementation aspects, including current commercial products, and trends in the development of energy-efficient hardware is also given. © 2013 IEEE

Greening the Airwaves with Collaborating Mobile Network Operators

Base station sharing is currently considered one of the most promising solutions for reducing the energy consumption costs of cellular networks. This paper presents a game theoretic framework for the study of such cooperative solutions where different mobile network operators (MNOs) decide to switch off subsets of their base stations during off-peak hours and roam their traffic to the remaining stations. The solution is based on a detailed optimization framework that determines exactly which base stations should remain active and how much traffic each one of them should serve, so as to maximize the aggregate energy savings. Accordingly, using the axiomatic Shapley value rule, it is determined how the benefits from the cooperation, i.e., the cost savings, should be dispersed among the cooperating MNOs. It is proved that this coalitional game with transferrable utilities has a nonempty core, and thus there exists a cooperation solution that incentivizes the participation of all operators. Moreover, using a thorough numerical analysis, it is shown that the benefits achieved with the implementation of the cooperation strategy depend mainly on the power consumption characteristics of the MNOs, which in turn are related to the number, type, and technology of their base stations. Overall, the energy savings are found to be most sensitive to the technology of the used base stations, and more precisely to the no-load base station energy consumption which defines the energy waste in a network. © 2002-2012 IEEE

Final phase-resolving Boussinesq-type models

The design of structures to be built in the nearshore region generally involves the evaluation of different possible layouts, under the effects of local wave and cunents conditions, with the aim of minimizing costs and maximizing the desired results. In particular the design of lowcrested structures involves optimisation of several parameters, which influence both the position, and the shape of the structures. The possible layout of the structures to be designed can be tested experimentally in wave tanks and wave flumes using adequate scale models. An alternative and attractive procedure is to employ suitable numerical and mathematical models. In principle, a very advanced numerical model, able to conectly simulate all the nearshore phenomena (turbulence, waves, currents, sediment transport, etc.) could be equivalent or even superior to a physical model. In practice, the numerical models currently employed in engineering activities, use several assumptions and simplifications: the phenomena that can be simulated strictly depend on the governing equations solved by the model. Indeed, the great advantage of numerical and mathematica! models is that their application is usually much less expensive than physical ones: it is certainly more economie to modify a computer file describing the bathymetry of the area under investigation than rebuild a physical model layout. This report is structured into two discrete sections, the first one contributed by AUTh and the second one by UR3. In the first section a 2DH higher-order Boussinesq-type model combined with a porous flow model, developed tor simulating flow around porous submerged structures is presented. On the other hand, in the second section enhancements on the applicability of Boussinesq-type equations (BTE) into the surf and swash zone are described.Delo