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Online Conference on Green Communications (GreenCom), 2011 IEEE

Date 26-29 Sept. 2011

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Displaying Results 1 - 25 of 27
  • [Copyright notice]

    Page(s): i
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    Freely Available from IEEE
  • Welcome from the general chairs

    Page(s): ii
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  • Welcome from the TPC chairs

    Page(s): iii
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    Freely Available from IEEE
  • Program

    Page(s): iv - vii
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  • Committees

    Page(s): viii
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  • Home energy management system for the residential load control based on the price prediction

    Page(s): 1 - 6
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (907 KB) |  | HTML iconHTML  

    This paper describes a home energy management system (HEMS) for the residential load control based on the price prediction. Smart metering and two-way communication based on the home area network can provide detail information of energy consumption patterns and controlling to appliances at home. The HEMS consists of the prices prediction, load scheduler and energy consumption monitor. The electricity pricing models are discussed to provide the price prediction capability. Then, the load scheduler is used to control the residential load with an aim at reducing the total energy cost. In addition, the smart meter and smart switchers are utilized to collect and monitor the energy consumption in the house. At last, a test-bed is constructed and the experiment results show that the HEMS based on the price prediction reduces the daily electricity expenditures by 22.2% as well as the peak-to-average-radio (PAR) by 35.5% in the load demand. View full abstract»

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  • Stochastic charging management for plug-in electric vehicles in smart microgrids fueled by renewable energy sources

    Page(s): 7 - 12
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (618 KB) |  | HTML iconHTML  

    Charging electric vehicles (EVs) from smart microgrids fueled by renewable energy resources is becoming a popular green approach. Although some works have been done about renewable energy sources and EVs in smart microgrids, the stochastic characteristics and the dynamic interplay between these two important green solutions should be carefully considered. Furthermore, one of the important performance metrics, service availability for EVs, is largely ignored in the existing works. In this paper, we study the charging policies in smart microgrids with EVs and renewable energy sources. We analyze service availability under different charging policies. Numerical results are presented to show the performance of different charging policies. View full abstract»

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  • Energy efficient wavelet based OFDM for V-BLAST MIMO Wireless Sensor Networks

    Page(s): 13 - 17
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (568 KB) |  | HTML iconHTML  

    In this paper, Wavelet based Orthogonal Frequency Division Multiplexing (WOFDM) is proposed as the primary modulation technique for Multi-Input Multi-Output (MIMO) Wireless Sensor Networks (WSNs) based on Vertical Bell Labs Layered Space-Time (V-BLAST) architecture. The BER and energy performance of WOFDM is analyzed and compared with other well-known modulation techniques. By exploiting the properties of WOFDM such as one dimensional constellation and low Peak-to-Average-Power Ratio (PAPR), simpler RF section can be designed for energy-efficient and high data-rate WSNs. View full abstract»

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  • On the minimization of power consumption in base stations using on/off power amplifiers

    Page(s): 18 - 23
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB) |  | HTML iconHTML  

    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. View full abstract»

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  • Joint MMSE transmit diversity optimization and relay selection for cooperative MIMO systems using discrete stochastic algorithms

    Page(s): 24 - 29
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (321 KB) |  | HTML iconHTML  

    This paper presents joint transmit diversity selection (TDS) and relay selection (RS) algorithms based on discrete stochastic optimization for a multi-relay cooperative MIMO system. A two-phase, decode-and-forward (DF) network with a non-negligible direct path is considered where linear minimum mean square error (MMSE) receivers are used at all nodes. TDS and RS are performed jointly with continuous least squares channel estimation and no transmit preprocessing is required. RS removes relays from consideration by TDS and generates an optimized set from which TDS is made, improving the convergence, performance, complexity and energy consumption of the TDS process whilst maintaining low feedback requirements. The performance of the proposed schemes is evaluated via mean square error (MSE), bit-error rate (BER) and complexity comparisons. The results show that the proposed schemes outperform cooperative transmission with and without TDS in terms of diversity, MSE and BER, and match that of the optimum exhaustive solutions whilst making considerable complexity and energy savings. View full abstract»

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  • Minimum energy and maximum capacity paths in multi hop wireless networks

    Page(s): 30 - 35
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB) |  | HTML iconHTML  

    Multi hop cellular networks have the potential of higher capacity and less energy consumption than their traditional single hop counterparts. However, to achieve meaningful performance gains, effective routing strategies are needed. From the perspective that both maximum throughput capacity and minimum energy consumption are equally desirable objectives, we develop efficient polynomial time algorithms to construct maximum capacity paths, minimum energy paths and maximum capacity paths with minimum energy or vice-versa. View full abstract»

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  • Impact of efficient power amplifiers in wireless access

    Page(s): 36 - 40
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (386 KB) |  | HTML iconHTML  

    Energy consumption of next generation radio access network is posing a deep impact on CO2 emission and network operating cost. In a macro site, radio equipment dominates the power consumption. Specifically, the power amplifiers consume 70% of the total input power. In case of WCDMA and OFDMA, the Traditional Power Amplifier (TPA) suffers from low efficiency due to the non-constant envelope signals. To improve efficiency in case of these kinds of signals, deployment of Envelope Tracking Power Amplifier (ET-PA) is a viable solution. In this paper, the efficiency vs. output power characteristics of the ET-PA has been modeled. Moreover, by carrying out system level simulation in WCDMA network scenario, we show that 7-15% energy can be saved by replacing TPA by ET-PA. View full abstract»

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  • A green router with built-in renewable energy module: Design, implementation and evaluation

    Page(s): 41 - 46
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2157 KB) |  | HTML iconHTML  

    Contemporary telecommunication systems are rapidly growing. High transmission speed and power consumption in such networks are an increasing concern. Therefore, building blocks of such networks need improvements in different aspects of their characteristics. In this paper we present an Open Source low power router which supports renewable energy by using an ultracapacitor based energy compatibility module. The described router achieves a packet rate of 580 kpps and a maximum throughput of 2.8 Gbps, consuming approximately 25 Watts. The energy compatibility module consists of a scalable design with low maintenance requirements. Our measurements show that the mentioned energy module has an efficiency of above 90%. View full abstract»

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  • Dynamic pricing for demand-side management in the smart grid

    Page(s): 47 - 51
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (521 KB) |  | HTML iconHTML  

    Intermittent renewable energy sources and the use of smart meters introduce a significant challenge for the reliability of the smart grid. Real-time pricing is an important demand-side management mechanism for improving smart grid reliability through dynamically changing or shifting the electricity consumption of users. Presently, the dynamic real-time pricing research in the smart grid mainly focuses on the interactions between a single utility company/retailer and its users. In this paper, we consider electricity liberalization, where more than one electricity retailer can co-exist in each region, and the retailers compete or cooperate with each other to achieve the highest individual or combined revenue. Two types of electricity users are considered in this paper: traditional electricity users who pay a fixed price and opportunistic electricity users who may change the electricity demand or even turn to another electricity retailer. Two game formulations are described for the proposed real-time pricing scheme. One formulation is proposed for a totally competitive environment. Another game formulation is proposed for a cooperative environment. Some simulation results are presented to show the effectiveness of the proposed real-time pricing scheme. View full abstract»

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  • Architecture model choices for a Smart Grid home network

    Page(s): 52 - 57
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1229 KB) |  | HTML iconHTML  

    Different architectural models for a Smart Grid home network, based on centralized and distributed control options, are proposed in order to enable the integration of smart devices into a Utility's demand/response infrastructure. The models explore the role of the home gateway and the smart meter for enabling the Smart Grid home architecture. This paper evaluates the models using a wide range of criteria such as scalability, security, demand response control, privacy, integration of the home local area network and flexibility. Architecture issues related to standardization and regulations and their impact on the models are also discussed. View full abstract»

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  • Auctioning game based Demand Response scheduling in smart grid

    Page(s): 58 - 63
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (559 KB) |  | HTML iconHTML  

    Matching demand to supply is one of the key features of smart grid infrastructure. Transforming conventional static customers into active participants who interact with the electrical utility in real time is the central idea of Demand Response (DR)Demand Side Management (DSM) in smart grid. In this paper, we decouple utility cost minimization and customer social welfare maximization into two stages. Since the utility is usually more risk averse than risk neutral in real life, this decoupling approach is more realistic than the usually adopted optimization setup, in which the two objectives are combined in a single weighted sum. With a block processing model introduced, in the first stage a convex optimization problem is formulated to minimize utility's generation cost and delay operation cost. An optimal load demand scheduling solution, of the form of water-filling, is derived analytically. Based on the optimal load profile generated in this first stage, repeated Vickrey auctions over time intervals are adopted to allocate load demands among customers while maximizing the social welfare. Despite the fact that truthful bidding is a weakly dominant strategy for all customers in the auctioning game, collusive equilibria do exist and jeopardize utility's profit severely. Analysis on the structure of the Bayesian Nash equilibrium solutions shows that by introducing a positive reserve price the Vickrey auction can be made to be more robust against such collusion by customers. Moreover the corresponding Bayesian Nash equilibrium is essentially unique and guarantees the basic profit of the utility. We further discuss how customers' valuations and bidding strategies change over time for the repeated Vickrey auction model. Simulation results emphasizing the influences of reserve price and time interval size on utility's profit is also presented. View full abstract»

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  • Green communications by demand shaping and user-in-the-loop tariff-based control

    Page(s): 64 - 69
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (367 KB) |  | HTML iconHTML  

    The new field of green communications can be divided into a) energy-efficient communications equipment or b) using information and communication technology to improve the world to become more energy aware. Mobile data traffic and utility energy consumption have a lot in common. There is a limited supply due to limited resources, and only growth (of quantities, technology) can increase this, at the cost of a higher carbon footprint. The green index is defined here for cellular wireless. On the other hand there is a demand which is user-generated, variable over time and space, and ever increasing at a fast pace. Flat rates or almost flat utility tariffs have spoiled users and established high user expectations. Instead of engineering for the growth of supply, this paper investigates how to engineer for controlling the demand side. Dealing with congestion is a consequence of the supply=demand regime and the end of overprovisioning. New tariffs are required that are tailored to the major QoS classes and help to shape demand at the user and application level. This paper investigates QoS-aware demand shaping and control by user-in-the-loop and tariff-based control. View full abstract»

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  • Performance modeling for two-hop relay with node selfishness in delay tolerant networks

    Page(s): 70 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (356 KB) |  | HTML iconHTML  

    Delay tolerant networks (DTNs) rely on the mobility of nodes and sequences of their contacts to compensate for lack of continuous connectivity and thus enable messages to be delivered from end to end in a “store-carry-forward” way. Since each node may also need to deliver out its locally generated message, in addition to carrying and forwarding messages for other nodes, the node may become more willing to forward its own message rather than that of others when it encounters some node. This kind of selfish behaviors may become much more significant when the nodes are operating under both QoS requirements (e.g., delivery delay requirements) and energy constraints. In this paper, we analytically explore how this kind of selfish behaviors will influence the delivery performance of the two-hop relay in the challenging DTNs. In particular, a continuous time Markov chain-based theoretical framework is developed to model the complicated message delivery process. With the help of the theoretical framework, closed-form expressions are further derived for both the expected delivery delay and the expected delivery cost, where the important node selfishness issue is carefully incorporated into the analysis. View full abstract»

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  • Balancing peer and server energy consumption in large peer-to-peer file distribution systems

    Page(s): 76 - 81
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (418 KB) |  | HTML iconHTML  

    Network induced energy consumption is a significant fraction of all ICT energy consumption. This paper investigates the most energy efficient way to distribute a file to a large number of recipients. It is shown that using peer-to-peer and naively minimizing the transfer time results in energy consumption that is an order of magnitude larger than simply distributing directly from a server, but that with careful management peer-to-peer systems can reduce the server's cost without increasing overall energy consumption. View full abstract»

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  • Energy-efficient non-cooperative resource allocation in multi-cell OFDMA systems with multiple base station antennas

    Page(s): 82 - 87
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (533 KB) |  | HTML iconHTML  

    The problem of non-cooperative resource allocation in multi-cell uplink OFDMA systems with multiple base station antennas is considered in this paper. Non-cooperative games for subcarrier allocation and transmit power control are considered, aiming at maximizing the users' energy efficiency, measured in bit/Joule and representing the number of error-free delivered bits for each Joule of energy used for transmission. First a non-cooperative energy-efficient power control game is devised, and then the theory of potential games is employed to come up with a non-cooperative game for joint subcarrier and power allocation. Numerical results confirm that the proposed resource allocation schemes are effective in increasing the network energy efficiency, thus optimizing the use of the energy stored in the battery. View full abstract»

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  • Maximizing bits-per-Joule capacity over parallel channels

    Page(s): 88 - 91
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (400 KB) |  | HTML iconHTML  

    Bits-per-Joule capacity is measured in [bit/Joule] and denotes the maximum number of bits that can be reliably transmitted on a noisy channel for each Joule of energy used for transmission. In this paper properties of the bits-per-Joule capacity of the bandlimited additive white Gaussian noise (AWGN) channel are discussed. Then, for the case of independent parallel Gaussian channels, the problem of optimal power allocation maximizing the energy efficiency is considered, and comparisons with the classical rate-maximizing waterfilling strategy are given. View full abstract»

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  • Energy-efficient power control for MIMO time-varying channels

    Page(s): 92 - 97
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (525 KB) |  | HTML iconHTML  

    Fast rising data traffic in mobile communication entails an increase in its energy consumption, which may result in climate effects and high operation costs, unless measures are taken to enhance its energy efficiency (EE). As part of the endeavour towards higher EE, we present a power control policy that adapts to a time-varying channel for multiple antenna communication. We provide a power budget model that reflects the power expenditure of a base station, that even accounts for the power used for training which enables channel information at the transmitter. We apply the results to Rayleigh fading channels and compare them with a suboptimal power policy where a constant power allocation is applied at all times. The relationship between the EE and the antenna configuration is discussed. View full abstract»

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  • Analysing the energy consumption behaviour of WiFi networks

    Page(s): 98 - 104
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (418 KB) |  | HTML iconHTML  

    The continuous increase in the energy production cost, together with environmental sustainability issues, is leading research communities, governments and industries to focus their efforts on a reduction of the global CO2 footprint. Information and communication technologies, which represent the nervous system of the globalized economy and society, account for a significant percentage of the overall global energy consumption. While a number of solutions have been proposed to build new, energy-aware and `green' communication infrastructures, little attention has been devoted to measuring the actual impact through real-world measurements. In this paper, we focus on wireless access networks, and aim at experimentally investigating the fundamental relationship between traffic and power consumption for a typical wireless LAN based on the IEEE 802.11g standard. The insight obtained through the measurements can be used to develop reliable and realistic energy consumption models, on top of which novel energy aware protocols and algorithms can be designed and developed. View full abstract»

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  • Energy-aware load balancing for parallel packet processing engines

    Page(s): 105 - 112
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2184 KB) |  | HTML iconHTML  

    In this paper, we consider energy-aware network devices (e.g. routers, switches, etc.) able to trade their energy consumption for packet forwarding performance by means of both low power idle and adaptive rate schemes. We focus on state-of-the-art packet processing engines, which generally represent the most energy-starving components of network devices, and which are often composed of a number of parallel pipelines to “divide and conquer” the incoming traffic load. Our goal is to control both the power configuration of pipelines, and the way to distribute traffic flows among them, in order to optimize the trade-off between energy consumption and network performance indexes. With this aim, we propose and analyze a constrained optimization policy, which try to find the best trade-off between power consumption and packet latency times. In order to deeply understand the impact of such policy, a number of tests have been performed by using experimental data from SW router architectures and real-world traffic traces. View full abstract»

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  • GRiDA: A green distributed algorithm for backbone networks

    Page(s): 113 - 119
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (737 KB) |  | HTML iconHTML  

    In this work, we face the problem of reducing the power consumption of Internet backbone networks. We propose a novel algorithm, called GRiDA, to selectively switch off links in an Internet Service Provider IP-based network to reduce the system energy consumption. Differently from approaches that have been proposed in the literature, our solution is completely distributed among the nodes. It leverages link state protocol like OSPF to limit the amount of shared information, and to reduce the algorithm complexity. Moreover, GRiDA does not require the knowledge of the actual traffic matrix, an unrealistic assumption common to all other proposals. Results, obtained on realistic case studies, show that GRiDA achieves performance comparable to several existing centralized algorithms. View full abstract»

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