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Differentiated cooperative multiple access for multimedia communications over fading wireless networks

Lookup NU author(s): Tao Guo, Emeritus Professor Rolando Carrasco, Dr Wai Lok Woo


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The quality of service (QoS) support for multimedia communications faces a big challenge in a fading wireless network. On one hand, conventional automatic repeat request (ARQ) schemes are not effective for small-scale fading channels with correlated errors due to consecutive retransmission failures. On the other hand, large-scale fading due to propagation loss or shadowing severely limits transmission range. A novel differentiated cooperative medium access control (MAC) protocol, called DC-MAC, is proposed to enhance the QoS support for multimedia communications while supporting service differentiation based on the IEEE 802.11e architecture. By enabling cooperative ARQ, the retransmission is initiated from an appropriate transmission queue of an appropriate relay node instead of the original source. Since unnecessary and useless retransmissions may intensify the node contention and degrade the system performance contrarily, a novel negative acknowledgement feedback mechanism is introduced for loss distinguishing and channel estimation such that cooperative retransmission will be employed only when necessary and only by competent nodes. Extensive simulations are conducted on the OPNET platform to analyse the performances of DC-MAC under both small-scale and large-scale fading. Simulation results show that the proposed scheme significantly improves the performances of both multimedia applications and best-effort data applications in terms of throughput, delay and coverage with moderate user contention.

Publication metadata

Author(s): Guo T, Carrasco RA, Woo WL

Publication type: Article

Publication status: Published

Journal: IET Communications

Year: 2009

Volume: 3

Issue: 6

Pages: 1005-1015

ISSN (print): 1751-8628

ISSN (electronic): 1751-8636

Publisher: The Institution of Engineering and Technology


DOI: 10.1049/iet-com.2008.0130


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