January 1, 1999 - August 1, 2002

It is well-known that TCP performs poorly in wireless a environment. This project involves an empirical performance analysis of TCP on Cellular Digital Packet Data (CDPD), Bluetooth and Wireless LAN (WLAN). This analysis brings out the weaknesses of TCP in realistic conditions. We also describe the design of CentaurusComm, a message based transport protocol designed to perform well in low bandwidth networks and resource poor devices. In particular, CentaurusComm is optimized to handle data exchanges consisting of short message sizes. Typical mobile devices used in the experiments included Palm Pilots. We show that TCP performance on CDPD is very poor because of its low bandwidth and high latency. CentaurusComm outperforms TCP on CDPD. We show that on Bluetooth, which has higher bandwidth and lower latency than CDPD, both protocols perform comparably. On WLAN, which has the highest bandwidth of all three technologies, CentaurusComm performs comparably to TCP with a reduced window size.

We are currently working on an improved version of CentaurusComm. We propose to evaluate its performance on a reduced Bluetooth stack consisting of only the minimum required layers.

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  1. Anupam Joshi



  1. L. Kagal, V. Korolev, S. Avancha, A. Joshi, T. Finin, and Y. Yesha, "Centaurus : An Infrastructure for Service Management in Ubiquitous Computing", Article, ACM Wireless Networks Journal, November 2002, 2748 downloads, 19 citations.


  1. S. Avancha, V. Korolev, A. Joshi, and T. Finin, "Transport Protocols in Wireless Networks", InProceedings, Proceedings of the Tenth International Conference on Computer Communications and Networks, October 2001, 4292 downloads, 6 citations.
  2. L. Kagal, V. Korolev, H. Chen, A. Joshi, and T. Finin, "Centaurus : A Framework for Intelligent Services in a Mobile Environment", InProceedings, International Workshop of Smart Appliances and Wearable Computing at the 21st International Conference of Distributed Computing Systems, April 2001, 6183 downloads, 57 citations.

Research Areas

  1. Mobile Computing