Technical University in Zvolen, 24 T.G. Masaryk Street, 96001 Zvolen, Slovak Republic;
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Our goal is to create an eco-friendly network for the collection of data from the environment. The network must be energy-independent with the use of renewable energy sources. As a backup power source in the event of unfavourable weather conditions supercapacitors and other environmental friendly energy storage technologies can be used. Our proposed data network needs to be energy efficient and be able to manage itself without any external supervision.
Keywords: communication network, energy harvesting, environment monitoring, eco-friendly technology, energy accumulation, fuel cells
Huawei Technologies Sweden AB, Skalholtsgatan 9, 16494 Kista, Sweden;
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The general trend for fixed broadband is that FTTx will overtake ADSL platforms and the number of FTTx subscribers is increasing exponentially. Moreover, it is likely that the ozone depletion potential (ODP) of dinitrogen oxide (N2O) and the aquatic acidification potential (AAP) of CO2 have been underestimated in LCA studies. The aim of this study is for the first time to assess the ODP and AAP of different FTTx network deployments in Italy adding the most recent characterization factors for N2O and CO2. An LCA case study was conducted covering three FTTx deployments (FTTC is compared to FTTB and FTTH) for 10,000 homes during one year in Italy. The focus is primarily on ODP and AP results in different life cycle phases. The ODP results suggest, using 0.017 kg/kg instead of 0 kg/kg as CFC-11e factor for N2O, for the greenfield/high power customer premise equipment (CPE) scenario, that FTTB, FTTC, and FTTH all rises from around 80–100 gram to around 600–700 gram CFC-11e/year dominated by the use and deployment stages. For AAP, with 1.752 kg/kg as SO2e factor for CO2 instead of 0 kg/kg, the rise is from 5–6 tons to 1,500–1,800 tons SO2e/year. The weight of the use stage is increasing with these new characterization indices. For FTTC controlling the power of the CPE is more important than the technique used for deployment. However, for FTTB and FTTH the deployment technique becomes almost as important as the power mode. Concerning FTTH, the main drivers for CFC-11e footprint are the electricity usage of the home gateways (HGWs), their manufacturing, and the use of diesel trucks in traditional civil works and mini-trench deployment. The inclusion of “average” bandwidth gives an advantage for FTTH as more data can be transferred more efficient and faster. For brownfield deployment in Italy (low power CPEs), FTTH architecture has the lowest amount of total CFC-11e emissions (appr. 130 grams). One of the most important criteria, from ozone depletion point of view, when choosing an FTTx network, is whether fiber has been deployed or not. Including the ODP factor for N2O increases the ODP score by 430–660% for the present systems. The increase for AAP is dramatic and shall be interpreted as a suggestion to include CO2 acidification in further LCIA research.
Keywords: aquatic acidification, CO2, FTTx, FTTH, life cycle assessment, N2O, optical fiber networks, ozone depletion
Computer Engineering Department, Kuwait University, Kuwait;
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Green computing provides techniques to reduce the wastage of energy, making it very critical to the development of IT systems due to the increasing power and energy needed now-a-days to run data centers. Green metrics play a vital role in green computing since they are criteria for evaluating the green performance of the large scale IT systems. Green computing metrics need to be defined to measure power costs and energy consumption. Measuring the amount of energy consumed by IT systems is a direct way of quantizing the amount of energy wasted or used efficiently by data centers. Energy awareness in applications and data centers can be obtained and calculated through green metrics such as the Green Performance Indicators (GPIs). The GPIs are classified into four classes: IT Resource Usage GPIs that compute resource usage, the Application Lifecycle KPIs that define efforts required to develop or redesign applications and reconfigure IT-infrastructure, the Energy Impact GPIs that represent the environmental impact of data centers, and the Organizational GPIs that describe organizational factors. Dividing the GPIs into four classes is an approach accepted in the EU Project GAMES. Many metrics have been identified by many associations, but there still yet to exist a framework in which a set of metrics are defined and used by applications and data centers to measure energy efficiency. This paper is a survey that sums up all the known metrics defined by almost all associations, and explicitly states their different units, scopes, and most importantly compares between them to define similarities and replacements that may exist. Exact similarities may help eliminate metrics whose measurements can be accomplished by another metric. The gathered GPIs are defined into the four main classes mentioned above and frameworks built based on the similarities found in each class, are developed. We also define a framework for the relationship between green computing and GPIs to illustrate how GPIs are incorporated in the process. Since GPIs measure different factors related to energy consumption, they may have different units. We furthermore compare and critique different approaches to unify the various units of the different metrics, and implement one of the techniques on most of the metrics mentioned below with some improvements. We introduce the idea of correlations which can measure the amount of similarities found between the metrics to reduce the number of metrics to unify.
Keywords: Green Computing, Green Performance Indicators (GPI), Key Performance Service Indictors (KPI)
Faculty of Electrical Engineering, University of Montenegro, Podgorica, Montenegro;
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It has been shown that cooperative communication schemes can solve many of the issues faced by future broadband WWAN and WLAN networks. It is about communication concept based on resource sharing and coordination among terminals in wireless network that provides significant performance improvements in terms of increased coverage, data rates, capacity, reliability, spectral and energy efficiency. This paper gives detailed overview of cooperative communication concept based on replacement of direct communication link between source and destination with several shorter links using network terminals called relays. Several, so called fixed relaying techniques, are described: amplify-and-forward fixed gain (AF FG), amplify-and-forward variable gain (AF VG) and decode-and-forward (DF). Appropriate analytical models for outage probability, bit error rate and system capacity values are presented. Further on, assuming Rayleigh fading channels, comparison of the presented relaying techniques are performed, enabling identification of optimal signal transmission scenarios for cooperative communication systems.
Keywords: cooperative relaying, amplify-and-forward, decode-and-forward, outage probability, BER, capacity, energy efficiency
1Faculty of Electrical Engineering and Computing, University of Zagreb, Croatia;
2Center for TeleInfrastruktur, Aalborg University, 9220 Aalborg, Denmark;
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The complexity of wireless networks requires careful design with special attention to energy and bandwidth efficiency. The energy efficiency is of more importance due to increasing penetration of wireless systems in different battery-operated applications as well as more conscious global view on the need for “Greening the Earth”. Bandwidth efficiency is very important parameter, because it relates to frequency spectrum, which is naturally scarce resource. Thus spectrum sensing is an important part of “Green Engineering”. The “Cognitive Radio” (CR) technology sheds new light on unavailability of spectrum by managing radio resources in more systematic and efficient way. Around the Globe there is a coordinated move for Digital Switch over (DSO) by discontinuing analogue television transmission. This “Digital Dividend” (DD) has created a new spectrum opportunities for many new wireless technologies. We focus on the scope and nature of opportunities for white space created by DD for Indian scenarios. We discuss use cases for the exploitation of Television White Space (TVWS) suitable for rural India based on user’s and BS geo-location and user’s mobility followed by QoS requirements and recent regulatory activities.
Keywords: DD, cognitive radio, IEEE 802.11 af, TV white spaces, rural India, use cases, regulatory aspects