Godfrey Tan
ABSTRACT
Wireless local area networks (WLANs) based on a family of 802.11 technologies are becoming ubiquitous. These technologies support multiple data transmission rates. Transmitting at a lower data rate (by using a more resilient modulation scheme) increases the frame transmission time but reduces the bit error rate. In non-cooperative environments such as public hot-spots, individual nodes attempt to maximize their achieved throughput by adjusting the data rate or frame size used, irrespective of the impact of this on overall system performance.In a series of experiments, we demonstrate that the existing distributed MAC protocol encourages non-cooperative nodes to use globally inefficient transmission strategies that lead to degraded aggregate throughputs. We also show that by establishing independence between the allocation of the shared channel time and the strategies used by individual nodes, an improved MAC protocol can lead rational but non-cooperative nodes to make choices that increase aggregate throughputs by as much as 30% under some conditions.
- Martin Heusse, Franck Rousseau, Gilles Berger-Sabbatel, and Andrzej Duda. Performance anomaly of 802.11b. In INFOCOM, April 2003.Google Scholar
Cross Ref
- Gavin Holland, Nitin H. Vaidya, and Paramvir Bahl. A rate-adaptive MAC protocol for multi-hop wireless networks. In Mobile Computing and Networking, pages 236--251, 2001. Google ScholarDigital Library
- David Kotz, Calvin Newport, and Chip Elliott. The mistaken axioms of wireless-network research. Technical Report TR2003-467, Dept. of Computer Science, Dartmouth College, July 2003.Google Scholar
- Allen Miu, Godfrey Tan, Hari Balakrishnan, and John Apostolopoulos. Divert: Fine-grained Path Selection for Wireless LANs. In Proc. of ACM Mobisys 2004, Boston, MA, Jun 2004. Google ScholarDigital Library
- ns-2 Network Simulator. http://www.isi.edu/vint/nsnam/.Google Scholar
- R. Punnoose, P. Nikitin, and D. Stancil. Efficient simulation for Ricean fading within a packet simulator. In IEEE Vehicular Technology Conference, pages 764--767, 2000.Google Scholar
- T. S. Rappaport. Wireless Communications. Prentice Hall, Upper Saddle River, N.J., 1996. Google ScholarDigital Library
- B. Sadeghi, V. Kanodia, A. Sabharwal, and E. Knightly. Opportunistic media access for multirate ad hoc networks. In MOBICOM, sept 2002. Google ScholarDigital Library
- Godfrey Tan and John Guttag. Time-based Fairness Improves Performance in Multi-rate WLANs. In Proc. of the Usenix Annual Technical Conference, Boston, MA, June 2004. Google ScholarDigital Library
- Wi-Fi Alliance Web Site, http://www.wi-fi.org.Google Scholar
- Long-term time-share guarantees are necessary for wireless LANs
Recommendations
A Medium Access Control Scheme for Wireless LANs with Constant-Time Contention
In today's wireless networks, stations using the IEEE 802.11 Standard contend for the channel using the Distributed Coordination Function (DCF). Research has shown that DCF's performance degrades especially with the large number of stations. This ...
Two-step multipolling MAC protocol for wireless LANs
The IEEE 802.11 standard defines two coordination functions: distributed coordination function (DCF) and point coordination function (PCF). These coordination functions coordinate the shared wireless medium. The PCF uses a centralized polling-based ...
Comments