Achieving Flow Isolation in 802.11 Networks with the DTT Scheduler

  • Rosario G. Garroppo
  • Stefano Giordano
  • Stefano Lucetti
  • Luca Tavanti
Part of the Lecture Notes in Computer Science book series (LNCS, volume 3883)


Though the IEEE 802.11 standard has reached wide acceptance, its main access function, the Distributed Coordination Function (DCF), still suffers from some relevant problems coming from the specific features of the wireless channel. By means of simulation, we analyse the performance anomaly and the “inter-flow blocking” problems, highlighting the mechanisms that generate them. Starting from these insights, we propose a simple centralized channel aware scheduling algorithm, named Deficit Transmission Time (DTT). The basic principle under the DTT is measuring the channel quality in terms of frame transmission times. This measurement is then used to take scheduling decisions that guarantee each downlink flow an equal time share of the channel. The proposed scheduler has been developed and deployed in a Linux-based prototype AP to experimentally evaluate its performance. The results clearly show the improvements introduced by the DTT in terms of flow isolation and reduction of the effects of the performance anomaly.


Medium Access Control Access Point Distribute Coordination Function Medium Access Control Layer Channel Quality 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Rosario G. Garroppo
    • 1
  • Stefano Giordano
    • 1
  • Stefano Lucetti
    • 1
  • Luca Tavanti
    • 1
  1. 1.Dipartimento di Ingegneria dell’InformazioneUniversità di PisaPisaItaly

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