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Download or read book Energy Efficient Cooperative Communication in Wireless Sensor Networks Subject to Frequency-selective Fading written by Jianjie Tian (‡e author) and published by . This book was released on 2017 with total page 167 pages. Available in PDF, EPUB and Kindle. Book excerpt: Energy efficient cooperative diversity techniques are investigated in this thesis with the aim of improving the energy efficiency of wireless sensor networks (WSNs) in the presence of additive white Gaussian noise (AWGN) and frequency-selective Rayleigh fading without degrading the reliability of data transmission. The studies reported mainly focus the theoretical aspects of aiming establishing the feasibility of employing cooperative diversity techniques in WSNs (subject to AWGN and frequency-selective Rayleigh fading) to effectively improve the network’s energy efficiency in the physical layer. With improvements to energy efficiency, the operational lifetime of WSN applications operating in indoor environments can be prolonged.A mathematical model of a single input single output (SISO) wireless communication system with direct sequence spread spectrum (DSSS) transceivers in the presence of AWGN and frequency-selective Rayleigh fading is proposed, modelled, theoretically analysed and simulated. In order to save the transmit energy consumption of sensor nodes, DSSS transceivers with chip-interleaving signal processing are considered as well. Analytical expressions of bit error rate (BER) in closed form are derived and analysed for wireless systems using DSSS transceivers, with or without chip-interleaving signal processing. Using the derived BER algorithms, the BER performances of virtual-multiple-input-single-output (vMISO), decode-and-forward (DF) and adaptive decode-and-forward (aDF) cooperation in WSNs subject to AWGN and frequency-selective Rayleigh fading are investigated as well.Performance evaluations are carried out based on the BER expressions and energy consumption models of vMISO, DF and aDF cooperation in terms of their optimal transmit power allocation and partner selection region. Because the energy expenditure of a sensor node can also be reduced by using the chip-interleaving signal processing, cooperative diversity (vMISO and DF) and chip-interleaved techniques are employed in combination to further improve the energy efficiency of WSNs operating over AWGN channels with frequency-selective Rayleigh fading. Furthermore,several simple partner selection heuristics are developed for energy efficient vMISO and DFcooperative schemes, which will enable resource-constrained sensor nodes to make cooperation decisions independently and autonomously. In summary, the analytical and simulation results demonstrate that the energy efficiency of WSNs subject to AWGN and frequency-selective Rayleigh fading can be significantly improved by implementing the cooperative diversity techniques and the chip interleaving technique, individually or in combination.