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Wireless Communications, IEEE

Issue 5 • Date October 2011

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Displaying Results 1 - 16 of 16
  • IEEE Wireless Communications - Front cover

    Publication Year: 2011 , Page(s): c1
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  • Table of contents

    Publication Year: 2011 , Page(s): 1
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  • Green communications: design the smart environment without harming ourselves [Message from the Editor-in-Chief]

    Publication Year: 2011 , Page(s): 2 - 3
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  • LTE-advanced and the evolution of LTE deployments

    Publication Year: 2011 , Page(s): 4 - 5
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (339 KB) |  | HTML iconHTML  

    The fourth generation (4G) wireless technology known as Long Term Evolution (LTE) allows cellular operators to use new and wider spectrum and complements third generation (3G) networks with higher user data rates, lower latency, and a flat Internet Protocol (IP)-based network architecture. The LTE standard was first published in March 2009 as part of the Third Generation Partnership Project (3GPP) Release 8 specifications. The specifications have been in development since 2005 when 3GPP defined LTE requirements and performance goals to significantly improve on the 3GPP Release 6 standard, which was at that point the state of the art. Achieving those goals required an evolution of both the air interface and the network architecture, now known as Evolved UMTS Terrestrial Radio Access Network (E-UTRAN) and Evolved Packet Core (EPC), respectively. The very first commercial LTE networks were deployed on a limited scale in Scandinavia at the end of 2009, and currently, large-scale deployments are taking place in several regions, including North America, Europe, and Asia. View full abstract»

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  • Scanning the literature

    Publication Year: 2011 , Page(s): 6
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  • Technologies for green radio communication networks

    Publication Year: 2011 , Page(s): 8 - 9
    Cited by:  Papers (1)
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  • Techniques for improving cellular radio base station energy efficiency

    Publication Year: 2011 , Page(s): 10 - 17
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (732 KB) |  | HTML iconHTML  

    The last ten years have witnessed explosive growth in the number of subscribers for mobile telephony. The technology has evolved from early voice only services to today's mobile wireless broadband (Internet) data delivery. The increasing use of wireless connectivity via smartphones and laptops has led to an exponential surge in network traffic. Meeting traffic demands will cause a significant increase in operator energy cost as an enlarged network of radio base stations will be needed to support mobile broadband effectively and maintain operational competitiveness. This article explores approaches that will assist in delivering significant energy efficiency gains in future wireless networks, easing the burden on network operators. It investigates three approaches to saving energy in future wireless networks. These include sleep mode techniques to switch off radio transmissions whenever possible; femtocell and relay deployments; and multiple antenna wireless systems. The impact of these approaches on achieving energy-efficient wireless communication systems is discussed. View full abstract»

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  • Energy- and cost-efficient ultra-high-capacity wireless access

    Publication Year: 2011 , Page(s): 18 - 24
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (436 KB) |  | HTML iconHTML  

    Mobile communication networks alone today consume 0.5 percent of the global energy supply. Meeting the rapidly increasing demand for more capacity in wireless broadband access will further increase the energy consumption. Operators are now facing both investing in denser and denser networks as well as increased energy cost. Traditional design paradigms, based on assumptions of spectrum shortage and high cost base station sites, have produced current cellular systems based on 3G and 4G (LTE) standards. The latter ones are characterized by very high spectrum efficiency, but low energy efficiency. Deployment has favored strategies with few high-power bases stations with complex antenna systems. The key method for indoor coverage has so far been to literally "blast signals through walls" - a solution that is neither energy-efficient nor very sound from a radiation perspective. As environmental aspects may be perceived as important from a societal perspective, the cost remains the short- to medium-term concern for operators of future mobile broadband systems. What becomes evident now is that the so far mostly neglected energy cost will be a major concern. Future system deployment has to balance infrastructure deployment, spectrum, and energy cost components. Ongoing incremental improvements in electronics and signal processing are bringing down the power consumption in the base station. However, these improvements are not enough to match the orders-of-magnitude increase in energy consumption cause by demands for more capacity. It is clear that solutions to this problem have to be found at the architectural level, not just by increasing the efficiency of individual components. In this article we propose a framework for a total cost analysis and survey some recent, more radical, "clean slate" approaches exploiting combinations of new spectrum opportunities, energy-efficient PHY layers, and novel deployment and backhauling strategies that target minimizing overall system co- - st. The latter involve network deployment tightly tailored to traffic requirements, using low-power micro base stations tailored specifically to decrease the power consumption compared to today's highpower macro base station schemes. To illustrate our findings, a power consumption model for mobile broadband access networks taking backhaul into account is presented, and the main trade-offs between infrastructure, energy, and spectrum costs are analyzed. We demonstrate optimal deployment strategies in some simple scenarios where a certain capacity has to be provided in a dense interference-limited scenario. View full abstract»

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  • TANGO: traffic-aware network planning and green operation

    Publication Year: 2011 , Page(s): 25 - 29
    Cited by:  Papers (25)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (987 KB) |  | HTML iconHTML  

    This article addresses the potential paradigm shift of the next-generation cellular networks from the viewpoint of energy efficiency. In particular, it reveals that networks planning and operation should be more energy efficiency oriented; and in the meantime, the radio resources distributed over different cellular networks, and base stations should be optimized in a global way to be globally resource-optimized and energy-efficient networks (GREEN). A new framework, called traffic-aware network planning and green operation (TANGO), is proposed toward GREEN. Some key technologies for the migration to TANGO are then presented and evaluated. Theoretical modeling and simulation studies show that TANGO schemes can greatly improve the energy efficiency of cellular networks, while keeping QoS at a satisfactory level. View full abstract»

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  • Network energy saving technologies for green wireless access networks

    Publication Year: 2011 , Page(s): 30 - 38
    Cited by:  Papers (37)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (477 KB) |  | HTML iconHTML  

    The energy consumption problem in the mobile industry has become crucial. For the sustainable growth of the mobile industry, energy efficiency (EE) of wireless systems has to be significantly improved. Plenty of efforts have been invested in achieving green wireless communications. This article provides an overview of network energy saving studies currently conducted in the 3GPP LTE standard body. The aim is to gain a better understanding of energy consumption and identify key EE research problems in wireless access networks. Classifying network energy saving technologies into the time, frequency, and spatial domains, the main solutions in each domain are described briefly. As presently the attention is mainly focused on solutions involving a single radio base station, we believe network solutions involving multiple networks/systems will be the most promising technologies toward green wireless access networks. View full abstract»

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  • How much energy is needed to run a wireless network?

    Publication Year: 2011 , Page(s): 40 - 49
    Cited by:  Papers (125)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (467 KB) |  | HTML iconHTML  

    In order to quantify the energy efficiency of a wireless network, the power consumption of the entire system needs to be captured. In this article, the necessary extensions with respect to existing performance evaluation frameworks are discussed. The most important addenda of the proposed energy efficiency evaluation framework (E3F) are a sophisticated power model for various base station types, as well as large-scale long-term traffic models. The BS power model maps the RF output power radiated at the antenna elements to the total supply power of a BS site. The proposed traffic model emulates the spatial distribution of the traffic demands over large geographical regions, including urban and rural areas, as well as temporal variations between peak and off-peak hours. Finally, the E3F is applied to quantify the energy efficiency of the downlink of a 3GPP LTE radio access network. View full abstract»

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  • Cell wilting and blossoming for energy efficiency

    Publication Year: 2011 , Page(s): 50 - 57
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2406 KB) |  | HTML iconHTML  

    In this article, we consider the adoption of sleep modes for the base stations of a cellular access network, focusing on the design of base station sleep and wake-up transients.. We discuss the main issues arising with this approach, and we focus on the design of base station sleep and wake-up transients, also known as cell wilting and blossoming. The performance of the proposed procedures is evaluated in a realistic test scenario, and the results show that sleep and wake-up transients are short, lasting at most 30 seconds. View full abstract»

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  • Dimensioning network deployment and resource management in green mesh networks

    Publication Year: 2011 , Page(s): 58 - 65
    Cited by:  Papers (12)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (466 KB) |  | HTML iconHTML  

    In this article, network deployment and resource management issues are revisited in the context of green radio communication networks with sustainable energy supply. It is argued that under the green network paradigm powered by renewable energy, the fundamental design criterion and main performance metric have shifted from energy efficiency to energy sustainability. As an effort to this end, in this article, new network solutions are proposed with an objective of improving network sustainability; the proposed solutions ensure that dynamically harvested energy can sustain the traffic demands in the network. Specifically, the placement issue of green access points (i.e., APs powered by sustainable energy sources) is investigated to meet the energy and QoS demands of mobile users; and an adaptive resource management scheme is proposed to address the unreliability of renewable energy in QoS provisioning. It is shown that by mitigating the energy depletion probability of green APs, sustainable network performance can be significantly improved. View full abstract»

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  • Green last mile: how fiber-connected massively distributed antenna systems can save energy

    Publication Year: 2011 , Page(s): 66 - 74
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (827 KB) |  | HTML iconHTML  

    We introduce a novel last-mile architecture that integrates the advantages of a distributed antenna system with centralized processing capability, connected through an optical fiber medium. The proposed broadband wireless access with fiber-connected massively distributed antenna system (BWA-FMDA) is capable of enhancing spectral efficiency of the network through coordinated multipoint transmissions at the femtocell scale. Furthermore, by shortening the lastmile communication link and lowering the power consumption, BWA-FMDA represents a viable green wireless access solution. Through our detailed and extensive simulation results, we demonstrate the potentially superior performance of BWA-FMDA in comparison with micro base station and femtocell deployments. View full abstract»

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  • Network cooperation for energy saving in green radio communications

    Publication Year: 2011 , Page(s): 76 - 81
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (338 KB) |  | HTML iconHTML  

    Financial and environmental considerations have motivated a trend in wireless communication network design and operation to minimize the amount of energy consumption. This trend is referred to as green radio communications. In this article, network cooperation is investigated as a means of energy saving. Networks with overlapped coverage can cooperate to reduce their energy consumption by alternately switching on and off their resources according to the traffic load conditions. We present an optimal resource on-off switching framework that adapts to the fluctuations in the traffic load and maximizes the amount of energy saving under service quality constraints in a cooperative networking environment. For the system model under consideration, unlike the existing solutions in the literature, the proposed technique can achieve energy saving while avoiding an increase in transmission power. Numerical results demonstrate the validity of the proposed technique. View full abstract»

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  • Power-efficient downlink transmission in multicell networks with limited wireless backhaul

    Publication Year: 2011 , Page(s): 82 - 88
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (386 KB) |  | HTML iconHTML  

    This article shows that division of a cell into tiers of smaller cells reduces power consumption. However, using the same frequency-time resources within multiple divided cells causes strong intercell interference. Given this circumstance, three beamforming techniques for multicell networks are presented to tackle the resultant challenging intercell interference environment. The schemes minimize the total transmit power across the coordinating base stations while simultaneously considering the quality of service of each user so that the latter is not unduly affected. Since the beamforming approaches require the circulation of information, an energy-efficient backhaul protocol is demonstrated. View full abstract»

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Aims & Scope

IEEE Wireless Communications Magazine deals with all technical and policy issues related to personalization, location-independent communications in all media.

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Meet Our Editors

Editor-in-Chief
Hsiao-Hwa Chen
Cheng Kung University, Taiwan