Title: An energy-efficient opportunistic relay assignment in wireless cooperative networks

Authors: Yindong Zhang; Liusheng Huang; Henan Zhao; Hongli Xu

Addresses: School of Computer Science and Technology, University of Science and Technology of China, Hefei 230027, China; Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou 215123, China ' School of Computer Science and Technology, University of Science and Technology of China, Hefei 230027, China; Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou 215123, China ' School of Computer Science and Technology, University of Science and Technology of China, Hefei 230027, China; Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou 215123, China ' School of Computer Science and Technology, University of Science and Technology of China, Hefei 230027, China; Suzhou Institute for Advanced Study, University of Science and Technology of China, Suzhou 215123, China

Abstract: It is very important to assign proper relays to transmission pairs so as to explore the efficiency of cooperative communication (CC). Most of the previous protocols were designed for ideal circumstances, where the Packet Drop Loss Ratio (PDLR) on each communication link is 0. Moreover, in hazardous surroundings, channel state is unstable, which is ignored by many algorithms. In this paper, we investigate an Opportunistic Relay Assignment Problem (ORAP) in a wireless cooperative network where channel state is unstable. We take into consideration the PFLR, while still guaranteeing energy-efficiency. We prove that this problem (ORAP) is NP-hard. A distributed algorithm, called DORAA, is proposed to solve this problem. We analyse the approximate performance ratio of DORAA. Our numerical results show that DORAA can reduce expected transmission time by 15.44% and save energy by 19.45% on average.

Keywords: cooperative communication; opportunistic assignment; energy efficiency; relay assignment; wireless networks; wireless sensor networks; cooperative WSNs; transmission time.

DOI: 10.1504/IJSNET.2013.055004

International Journal of Sensor Networks, 2013 Vol.13 No.3, pp.135 - 144

Published online: 24 Jun 2013 *

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