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چكيده انگليسي :

Energy Efficiency Analysis of Relay Based Wireless Communication Systems Mohammad Hossein Chinaei mh chinaei@ec iut ac ir Date of Submission 2014 16 8 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Mohammad Javad Omidi omidi@cc iut ac ir Abstract Today Energy efficiency EE is taking a more significant role in the design of modern communication systems One of the most crucial trade offs in the green communication frame work is the trade off between EE and Spectral Efficiency SE In traditional literature the EE was defined as information bits per unit of transmit energy however practical concerns result in taking circuit energy consumption into account for the energy consumption model ECM The EE metric has been redefined as information bits per unit of consumed energy not just transmit energy where an additional circuit power factor needs to be considered Also SE is defined as system throughput per unit of bandwidth is a widely accepted performance indicator of wireless networks The trade off between maximizing SE and EE in communication systems prompts desiners to balance the two metrics in future communication networks It is shown that by the increase of radio access points RAPs in a network relays are good examples of RAPs in wireless networks the energy consumption of the network without consideration of the circuitry power will be improved However a tangible proof or graph is not provided to conclude how relay cooperative communication can be helpful in improving EE In this thesis the basic concepts of green communication EE and relay based systems are reviewed The energy efficiency EE of a decode and forward DF relay system is studied where two sources communicate through a half duplex relay node in one way and two way relaying strategies Two way relaying is proposed as a cooperative scheme to improve the SE of one way relaying One way relaying leads to the loss of SE due to the pre log factor one half in the corresponding capacity expression however two way relaying avoids the pre log factor one half still uses half duplex equipment Both the circuitry power and the transmission power of all nodes are taken into consideration In addition three different coding schemes for two way DF relaying strategy are considered The aim is to maximize the EE of the system for a constant spectral efficiency SE For this purpose the transmission time and the transmission power of each node are optimized Simulations are used to compare the EE SE curve of different DF strategies with one way and two way amplify and forward AF strategies and direct transmission DT to find the best energy efficient strategy in different SE conditions Analytical and simulation results demonstrate that in low SE conditions DF relaying strategies are more energy efficient compared to AF strategies and DT However in high SE conditions the EE of two way AF relaying and DT strategy outperform some of the DF relaying strategies Also the impact of different circuitry power and different channel conditions on the EE SE curves are investigated Keywords Green communication Energy efficiency Relay based systems Resource allocationPDF created with pdfFactory Pro trial version www pdffactory com

چينائي، محمدحسين

بررسي بازده انرژي در سيستم هاي مخابرات بي سيم مبتني بر رله

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