Improving the latency of 802.11 hand-offs using neighbor graphs

ABSTRACT

The 802.11 IEEE Standard has enabled low cost and effective wireless LAN services (WLAN). With the sales and deployment of WLAN based networks exploding, many people believe that they will become the fourth generation cellular system (4G) or a major portion of it. However, the small cell size of WLAN creates frequent hand-offs for mobile users. If the latency of these hand-offs is high, as previous studies have shown, then the users of synchronous multimedia applications such as voice over IP (VoIP) will experience excessive jitter. The dominating factor in WLAN hand-offs has been shown to be the discovery of the candidate set of next access points. In this paper, we describe the use of a novel and efficient discovery method using neighbor graphs and non-overlap graphs. Our method reduces the total number of probed channels as well as the total time spent waiting on each channel. Our implementation results show that this approach reduces the overall probe time significantly when compared to other approaches. Furthermore, simulation results show that the effectiveness of our method improves as the number of non-overlapping channels increases, such as in the 5 GHz band used by the IEEE 802.11a standard.

REFERENCES

• 1: IEEE, "Part 11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications," IEEE Standard 802.11, 1999.
• 2: V. Nee, "New High-Rate Wireless LAN Standards," IEEE Communications Magazine, vol. 37, pp. 82--88, Dec. 1999.
• 3: D. Corner, J. Lin, and V. Russo, "An Architecture for a Campus-Scale Wireless Mobile Internet," Tech. Rep. CSD-TR 95-058, Purdue University, Computer Science Department.
• 4: A. Hills and D. Johnson, "A Wireless Data Network Infrastructure at Carnegie Mellon University," IEEE Personal Communications, vol. 3, pp. 56--63, Feb. 1996.
• 5: P. Bahl, A. Balachandran, and S. Venkatachary, "Secure Wireless Internet Access in Public Places," in Proceedings of IEEE Internationa Conference on Communications 2001, June 2001.
• 6: T. Cornall, B. Pentland, and P. Khee, "Improved Handover Performance in Wireless Mobile IPv6," in Communication Systems, 2002. ICCS 2002. The 8th International Conference on, vol. 2, pp. 857--861, Nov. 2002.
• 7: International Telecommunication Union, "General Characteristics of International Telephone Connections and International Telephone Circuits." ITU-TG.114, 1988.
• 8: R. Shirdokar, J. Kabara, and P. Krishnamurthy, "A QoS-based Indoor Wireless Data Network Design for VoIP," in Vehicular Technology Conference, 2001. VTC 2001 Fall. IEEE VTS 54th, vol. 4, pp. 2594--2598, Oct. 2001.
• 9: Arunesh Mishra , Minho Shin , William Arbaugh, An empirical analysis of the IEEE 802.11 MAC layer handoff process, ACM SIGCOMM Computer Communication Review, v.33 n.2, April 2003 [doi>10.1145/956981.956990]
• 10: F. K. Al-Bin-Ali, P. Boddupalli, and N. Davies, "An Inter-Access Point Handoff Mechanism for Wireless Network Management: The Sabino System," in ICNN 2003, 2003.
• 11: Lucent Technologies Inc., "IEEE 802.11 Channel Selection Guidelines," Tech. Rep. WaveLan Technical Bulletin 003/A, Nov. 1998.
• 12: Lucent Technologies Inc., "Roaming with WaveLAN/IEEE 802.11," Tech. Rep. WaveLan Technical Bulletin 021/A, Dec. 1998.
• 13: A. Mishra, M. Shin, and W. A. Arbaugh, "Context Caching using Neighbor Graphs for Fast Handoffs in a Wireless Network," in IEEE Infocom 2004, Mar. 2004.
• 14: Theodore Rappaport, Wireless Communications: Principles and Practice, Prentice Hall PTR, Upper Saddle River, NJ, 2001
• 15: Clint Smith , Daniel Collins, 3G Wireless Networks, McGraw-Hill, Inc., New York, NY, 2001
• 16: 3GPP, "Technical Specification Group Services and System Aspects; Vocabulary for 3gpp Specifications (Release 6)," Tech. Rep. 3GPP TR 21.905 v6.4.0, Sept. 2003.
• 17: G. P. Pollini, "Trends in Handover Design," IEEE Communications Magazine, Mar. 1996.
• 18: M. Gudmundson, "Analysis of Handover Algorithms," in IEEE Vehicular Technology Conference, VTC91, pp. 537--542, 1991.
• 19: N. Zhang and J. M. Holtzman, "Analysis of Handoff Algorithms using Both Absolute and Relative Measurements," IEEE Transactions on Vehicular Technology, vol. 45, pp. 174--179, Feb. 1996.
• 20: H. Aida , Y. Tamura , Y. Tobe , H. Tokuda, Wireless packet scheduling with signal-to-noise ratio monitoring, Proceedings of the 25th Annual IEEE Conference on Local Computer Networks, p.32, November 08-10, 2000
• 21: W. A. Arbaugh, N. Shankar, J. Wang, and K. Zhang, "Your 802.11 Network Has No Clothes," IEEE Wireless Communications Magazine, Dec. 2002.
• 22: IEEE, "Standards for Local and Metropolitan Area Networks: Standard for Port Based Network Access Control," IEEE Draft P802.1X/D11, Mar. 2001.
• 23: B. Aboba and D. Simon, "PPP EAP TLS Authentication Protocol," RFC 2716, Oct. 1999.
• 24: IEEE, "Draft Amendment to STANDARD FOR Telecommunications and Information Exchange Between Systems-LAN/MAN Specific Requirements. Part 11: Wireless Medium Access Control and Physical Layer(PHY) Specifications: Medium Access Control (MAC) Security Enhancements," IEEE Standard 802.11i, May 2003.
• 25: A. Mishra, M. Shin, and W. A. Arbaugh, "Pro-active Key Distribution using Neighbor Graphs," IEEE Wireless Communications Magazine, Feb. 2004.
• 26: D. B. Johnson, C. E. Perkins, and J. Arkko, "Mobility Support in IPv6," Internet Draft draft-ietf-mobileip-ipv6-18.txt, Internet Engineering Task Force (IETF), Jun. 2002.
• 27: IEEE, "Draft 5 Recommended Practice for Multi-Vendor Access Point Interoperability via an Inter-Access Point Protocol Across Distribution Systems Supporting IEEE 802.11 Operation," IEEE Draft 802.11f/D5, Jan. 2003.
• 28: J. Yee and H. Pezeshki-Esfahani, "Understanding Wireless LAN Performance Trade-Offs," Communication Systems Design, pp. 32--35, Nov. 2000.
• 29: David S. Johnson, Approximation algorithms for combinatorial problems, Proceedings of the fifth annual ACM symposium on Theory of computing, p.38-49, April 30-May 02, 1973, Austin, Texas, United States [doi>10.1145/800125.804034]
• 30: "Demarc Technologies Group." URL: http://www.demarctech.com.
• 31: R. Baird and M. Lynn, "Airjack Driver." http://802.11ninja.net/airjack.
• 32: "High Resolution POSIX Timers." http://sourceforge.net/projects/high-res-timers.
• 33: J. Yeo, S. Banergee, and A. Agrawala, "Measuring Traffic on the Wireless Medium: Experience and Pitfalls," Tech. Rep. CS-TR 4421, Dec. 2002.
• 34: R. Koodli, "Fast Handovers for Mobile IPv6," Internet Draft draft-ietf-mobileip-fast-mipv6-08.txt, Internet Engineering Task Force (IETF), Oct. 2003.
• 35: E. Shim, H. yu~Wei, Y. Chang, and R. Gitlin, "Low Latency Handoff for Wireless IP QoS with NeighborCasting," in Communications, 2002. ICC 2002. IEEE International Conference on, vol. 5, pp. 3245--3249, Apr. 2002.
• 36: L. Perato and K. Al~Agha, "Handover Prediction: User Approach versus Cell Approach," in Mobile and Wireless Communications Network, 2002. 4th International Workshop on, pp. 492--496, Sept. 2002.

INDEX TERMS

Primary Classification:
  C. Computer Systems Organization
  C.2 COMPUTER-COMMUNICATION NETWORKS
      C.2.1 Network Architecture and Design
          Subjects: Wireless communication

Additional Classification:
  E. Data
  E.1 DATA STRUCTURES

General Terms:
Design, Experimentation, Performance

Keywords:
802.11, WLAN, hand-off, mobility graph, neighbor graph, probing, scanning