3rd International ICST Conference on Mobile Multimedia Communications

Research Article

Adaptive Link Layer Protocols for Shared Wireless Links

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        author={George Xylomenos and Michael Makidis},
        title={Adaptive Link Layer Protocols for Shared Wireless Links},
        proceedings={3rd International ICST Conference on Mobile Multimedia Communications},
        keywords={UMTS RLC selective repeat link layer.},
  • George Xylomenos
    Michael Makidis
    Year: 2010
    Adaptive Link Layer Protocols for Shared Wireless Links
    DOI: 10.4108/ICST.MOBIMEDIA2007.1822
George Xylomenos1,*, Michael Makidis1,*
  • 1: Mobile Multimedia Laboratory Athens University of Economics and Business Patision 76, Athens 104 34, Greece
*Contact email: xgeorge@aueb.gr, mikem4600@gmail.com


The error prone nature of wireless links often necessitates the use of a link layer protocol to ensure acceptable application performance. While traditional link layers assume that they fully control the link, in most emerging wireless networks many sessions may dynamically share the link due to the presence of multiple contending users and/or applications. Such networks require link layers that can automatically adapt to bandwidth variations, offering good performance regardless of contention. To this end, we discuss two adaptive protocols, an Adaptive Selective Repeat (ASR) protocol that dynamically modifies its retransmission timeouts, and the Radio Link Control (RLC) protocol used by UMTS, an advanced protocol without retransmission timers. To assess the applicability of each approach, we measure the throughput achieved by File Transfer and Web Browsing over both protocols, with or without contention from a Media Distribution application, as well as the delay induced by these protocols to the contending application. Our results indicate that the complexity of RLC is not justified by its performance, as ASR nearly always outperforms it.