title   
  

On energy efficiency of routing with cooperative transmissions

Aksu, Aylin (2006) On energy efficiency of routing with cooperative transmissions. [Thesis]

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Official URL: http://risc01.sabanciuniv.edu/record=b1158357 (Table of Contents)

Abstract

Cooperative transmissions emulating multi-antenna systems may help reduce the total energy consumption in wireless networks. In this thesis, we define a virtual multiple-input single-output (vMISO) link to be established when a group of nodes (transmitters) jointly enable space-time communications with a single receiver. There has been plethora of research investigating physical layer issues of such systems; however, higher layer protocols that exploit vMISO links in ad hoc networks are still emerging. We present a novel approach in characterizing the optimal multi-hop vMISO routing in ad hoc networks. The key advantages of vMISO links that we exploit are the increase in transmission range and the decrease in the required transmission energy due to diversity gain. Specifically, under a high node density regime, we solve a nonlinear program that minimizes the total energy cost of reliable end-to-end transmissions by selecting the optimal cooperation set and the location of the next relay node at each hop. We characterize the optimal solution with respect to the reliability of the links, and for different fixed node transmission powers. Our results indicate that a multi-hop vMISO system is energy efficient only when a few nodes cooperate at each hop. We design a new greedy geographical vMISO routing protocol that is also suitable for sparse networks using the results determined under high node density regime. Also, we consider the network lifetime maximization problem in networks employing vMISO links. We formulated the network lifetime maximization with vMISO routing as a nonlinear program. Then, we presented a novel cooperation set selection and flow augmentation based routing heuristic that can significantly increase the network lifetime compared to Single-Input Single-Output (SISO) systems.

Item Type:Thesis
Uncontrolled Keywords:Energy efficiency. -- Cooperation. -- Routing
Subjects:T Technology > TK Electrical engineering. Electronics Nuclear engineering
ID Code:8303
Deposited By:IC-Cataloging
Deposited On:15 Apr 2008 16:13
Last Modified:27 Dec 2008 13:36

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