Fixed WiMAX Profit Maximisation with Energy Saving through Relay Sleep Modes and Cell Zooming
Fernando J. Velez1, Maria del Camino Noguera1, Oliver Holland2, and A. Hamid Aghvami2
1Instituto de Telecomunicações, DEM, Universidade da Beira Interior Faculdade de Engenharia, 6201-001 Covilhã, Portugal;
2Centre for Telecommunications Research, King’s College London, Strand London WC2R 2LS, United Kingdom;
In Fixed WiMAX, the cost/revenue optimisation function for radio and network planning incorporates the cost of building and maintaining the infrastructure and the impact of the available resources on revenues. Supported throughput typically decreases with larger cells due to the implied greater average distance of users from the base station, although the use of subchannelisation can keep throughput steady with a larger cell radius. The use of sectored base stations facilitates selection of higher order modulation and coding schemes in the cell and can improve throughput; however, sectored equipment is more expensive. Fortuitously, using Relay Stations (RSs) can reduce the deployment cost of such systems. In such a context, if RSs are put into sleep mode during the night and at weekends when they are not necessary, important energy savings can be achieved. With relays, only the consideration of tri-sectored Base Station (BS) antennas with K=3 (at the cost of extra channels, where 9 channels corresponds to a bandwidth of 31.5 MHz) obtains values of system throughput comparable to those without using relays. This is due to the more favourable frame format that is employed under the use of tri-sectored BS antennas. This paper shows that the application of cell zooming in conjunction with relays going into sleep mode at times of low load achieves a notable power saving, corresponding to 10% saving in operation and maintenance cost on average. Moreover, as it is assumed that the DL sub-frame format cannot be changed to a more favourable one, economic performance is better when RSs are deployed. It is however important to highlight that in the absence of RSs, economic performance is still reasonable (for tri-sectored and ominidirectional BSs, 700-800% and 400-450% profit, respectively), compared with the case where RSs are deployed (~1000% and ~900% profit, respectively).
Keywords: broadband communication, WiMAX, planning, economics, relays, green communications, cell zooming.
Introducing Energy Awareness in the Cognitive Management of Future Networks
Kostas Tsagkaris, George Athanasiou, Marios Logothetis, Yiouli Kritikou, Dimitrios Karvounas and Panagiotis Demestichas
Department of Digital Systems, University of Piraeus, 18534 Piraeus, Greece;
The current circumstances on a worldwide level urgently impose to exploit technology in order to reduce environmental pollution, CO2 emissions and waste. The current technologies and the provisioned evolution steps take into consideration these facts and contribute to achieve greener footprint. This paper describes technologies as important elements in the design of Energy-aware Future Networks. They comprise Energy-aware Opportunistic Networks and Traffic Engineering schemes that can be seen as two major extensions towards future networks in the wireless infrastructure-less and wired backhaul/core segments, respectively. In parallel, the role of Cognitive Management Systems for enhancing these technologies with intelligent features that can assist in the optimization of network performance goals, including green targets, is also pointed out. Several simulation results evince how the proposed schemes can contribute in achieving greener footprint in the context of Future Networks.
Keywords: cognitive management, energy-aware, green footprint, opportunistic networks, traffic engineering, future networks.
The Use of Mobile Communication in Traffic Incident Management Process
S. Mandzuka1, Z. Kljaić2 and P.Škorput1
1Department of Intelligent Transportation Systems, Faculty of Traffic Science, University of Zagreb, Vukeliceva 4, 10000 Zagreb, Croatia;
2Ericsson Nikola Tesla d.d., Krapinska 45, 10000 Zagreb, Croatia;
In cases of major traffic or other incidents it is very important to manage events dynamically in real time for a primary reason, i.e. in order to reduce death causalities and other technical and technological damages. A unique name for this system is Incident Management System. The critical point in the traffic incident management chain is the procedure after detecting the incident and the appropriate verification thereof. It is the process of informing other participants in road traffic. The paper gives a description of one such technology, known as Cell Broadcasting. A technological overview of the system along with its applications and experience in real-life environment is given here.
Keywords: intelligent transportation systems, Incident Management System, Cell Broadcasting, location based broadcasting.
A Heterogeneous Network for Energy Metering and Control
Enrico Paolini1, Andrea Giorgetti1, Simone Minardi2 and Marco Chiani1
1DEIS/WiLAB, University of Bologna, Via Venezia 52, 47521 Cesena (FC), Italy
2I.co. Srl, Rimini (RN), Italy;
We describe a heterogeneous network composed by wireless links and a power line communication (PLC) infrastructure, using the public lighting system. The network allows to measure consumption of gas, energy, water, etc., in an urban scenario with a large number of nodes, and to remotely control the lighting system for efficient energy usage. For the specific scenario where the network topology is known a priori, we describe a tool for network planning based on the simulation of the power line channel. Moreover, to improve PLC link throughput and reliability we analyze the possiblity to use multiple conductors to enable multiple input multiple output (MIMO) techniques. Finally, we describe a successfully implemented testbed for the proposed network.
Keywords: automatic meter reading, energy savings, heterogeneous networks, powerline communications,remote control
Energy Consumption of Personal Computing Including Portable Communication Devices
Pavel Somavat1 and Vinod Namboodiri2
1CCS Haryana Agricultural University;
2Department of Electrical Engineering and Computer Science, Wichita State University, Wichita, KS 26260, U.S.A;
In light of the increased awareness of global energy consumption, questions are being asked about the energy contribution of computing equipment. Although studies have documented the share of energy consumption by this type of equipment over the years, research has rarely characterized the increasing share contributed by the rapidly growing segment of portable, pervasive computing devices. Portable computing is widely predicted to be a dominant mode of computing and communication in the future, and accounting for its energy consumption is necessary to develop efficient practices. This work takes a fresh and updated look at energy consumption as the result of computing devices with regard to global consumption, and pays special attention to the contribution of portable computing devices. We further quantify the impact of energy consumed by the computing sector on the environment, and the cost of electricity for an average residential consumer. Finally, based on the results of this study, we provide recommendations for the computer networking community for sustainable portable/mobile computing.
Keywords: energy, electricity, computing, portable devices, environment, networking
Analysis of Power Consumption in OFDM Systems
Irena Orović, Nikola Žarić, Srdjan Stanković, Igor Radusinović and Zoran Veljović
Faculty of Electrical Engineering, University of Montenegro, 20000 Podgorica, Montenegro
The energy efficiency of various OFDM systems, such as optical, mobile, Wireless and WiMaX systems, has been analyzed in this paper. High peak to average power ratio that may appear in modulation process is one of the main problems in OFDM systems. The influence of subcarriers number and modulation techniques to the peak-to-average power ratio in different OFDM based systems has been studied. The results of analysis are presented in numerous figures and tables. The main goal is to provide a comparative study that can be used for an optimal system selection with predefined power consumption requirements.
Keywords: OFDM, peak-to-average power ratio, transmission systems.