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    Aggregation with fragment retransmission for very high-speed WLANs

    Li, Tianji and Ni, Qiang and Malone, David and Leith, Douglas J. and Turletti, Thierry and Xiao, Yang (2009) Aggregation with fragment retransmission for very high-speed WLANs. IEEE/ACM Transactions on Networking, 17 (2). pp. 591-604. ISSN 1063-6692 (In Press)

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    In upcoming very high-speed WLANs the physical layer (PHY) rate may reach 600 Mbps. To achieve high efficiency at the medium access control (MAC) layer, we identify fundamental properties that must be satisfied by any CSMA/CA based MAC layer and develop a novel scheme called Aggregation with Fragment Retransmission (AFR). In the AFR scheme, multiple packets are aggregated into and transmitted in a single large frame. If errors happen during the transmission, only the corrupted fragments of the large frame are retransmitted. An analytic model is developed to evaluate the throughput and delay performance of AFR over a noisy channel, and to compare AFR with competing schemes in the literature. Optimal frame and fragment sizes are calculated using this model. Transmission delays are minimised by using a zero-waiting mechanism where frames are transmitted immediately once the MAC wins a transmission opportunity. We prove that zero waiting can achieve maximum throughput. As a complement to the theoretical analysis, we investigate by simulations the impact of AFR on the performance of realistic application traffic with diverse requirements. We have implemented the AFR scheme in the NS-2 simulator and present detailed results for TCP, VoIP and HDTV traffic. The AFR scheme described was developed as part of the 802.11n working group work. The analysis presented here is general enough to be extended to the proposed scheme in the upcoming 802.11n standard. Trends indicated by our simulation results should extend to any well-designed aggregation scheme.

    Item Type: Article
    Additional Information: Copyright Notice "©2009 IEEE. Reprinted from IEEE/ACM Transactions on Networking. 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: Aggregation; Fragment Retransmission; Very High-Speed WLANs; Carrier sense multiple access; Telecommunication congestion control; Wireless LAN; Wireless channels; HDTV traffic; Collision avoidance; Local area network; Medium access control; Noisy channel; Physical layer; Transmission delay; Transport control protocol; Voice-over-Internet protocol; Wireless LAN; Zero-waiting mechanism; IEEE 802.11; IEEE 802.11n.
    Academic Unit: Faculty of Science and Engineering > Computer Science
    Faculty of Science and Engineering > Research Institutes > Hamilton Institute
    Item ID: 1202
    Identification Number:
    Depositing User: Tianji Li
    Date Deposited: 22 Jan 2009 14:19
    Journal or Publication Title: IEEE/ACM Transactions on Networking
    Publisher: Institute of Electrical and Electronics Engineers (IEEE)
    Refereed: Yes
    Use Licence: This item is available under a Creative Commons Attribution Non Commercial Share Alike Licence (CC BY-NC-SA). Details of this licence are available here

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