A practical adaptive pacing scheme for TCP in multihop wireless networks

  • Authors:
  • Sherif M. ElRakabawy;Christoph Lindemann

  • Affiliations:
  • Department of Computer Science, University of Leipzig, Leipzig, Germany;Department of Computer Science, University of Leipzig, Leipzig, Germany

  • Venue:
  • IEEE/ACM Transactions on Networking (TON)
  • Year:
  • 2011

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Abstract

We introduce and evaluate a feasible end-to-end congestion control algorithm for overcoming the severe deficiencies of TCP in IEEE 802.11 multihop wireless networks. Our approach, which we denote as TCP with Adaptive Pacing (TCP-AP), implements rate-based scheduling of transmissions within the TCP congestion window. The TCP source adaptively sets its transmission rate using an estimate of the current out-of-interference delay and the coefficient of variation of recently measured round-trip times. TCP-AP retains the end-to-end semantics of TCP and neither relies on modifications at the routing or the link layer nor requires cross-layer information from intermediate nodes along the path. As opposed to previous proposals that build on network simulators, we implement and evaluate our approach in a real wireless mesh test-bed comprising 20 nodes. In a comprehensive comparative performance study using our test-bed, we show that, depending on the current network state and traffic patterns, TCP-AP achieves up to 10 times more goodput than TCP NewReno, provides excellent fairness, and is highly responsive to changing network traffic conditions.