Asymmetric Cooperation among Wireless Relays with Linear Precoding

Devroye, Natasha and Mehta, Neelesh B and Molisch, Andreas F (2008) Asymmetric Cooperation among Wireless Relays with Linear Precoding. In: IEEE Transactions on Wireless Communications, 7 (12, Pa). pp. 5420-5430.

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Abstract

Wireless relays extend coverage, improve spectral efficiency, and enhance reliability and rates of wireless cellular communication systems. In this work, we introduce the fundamental notion of asymmetric cooperation among cooperating relays in cellular downlinks - different relays are party to different but overlapping knowledge about the messages transmitted from the base station. We argue that asymmetric cooperation arises naturally in most two-phase protocols in which the base station first transmits information to multiple relays that then cooperatively forward the information to the recipient mobile stations in the cell. For a system in which two relays are of the decode-and-forward type and cooperate using linear precoding to communicate with two mobile stations, we formulate the general, but complicated, throughput optimization problem and derive several results that considerably simplify the optimization. We show that under different channel configurations and fairness criteria, asymmetric cooperation is often the throughput-maximizing option. Under typical configurations, a 20-30% throughput enhancement is achieved compared to conventional full-cooperation systems.

Item Type:	Journal Article
Publication:	IEEE Transactions on Wireless Communications
Publisher:	IEEE
Additional Information:	Copyright of this article 2008 belongs to IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
Keywords:	Relays;fading channels;cooperation;linear precoding; asymmetry;SDMA; MIMO.
Department/Centre:	Division of Electrical Sciences > Electrical Communication Engineering > Electrical Communication Engineering - Technical Reports
Date Deposited:	01 May 2009 09:04
Last Modified:	19 Sep 2010 05:00
URI:	http://eprints.iisc.ac.in/id/eprint/18134

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