Journal of the Institute of Electronics Engineers of Korea TC (대한전자공학회논문지TC)

The Institute of Electronics and Information Engineers (대한전자공학회)
권호 표지

Congestion Control Algorithm for TCP Performance Enhancement by Bandwidth Measurement in Vertical Handoffs between Heterogeneous Wireless Networks

이기종 무선 망간 vortical handoff시 대역폭 측정을 통한 TCP 성능향상 혼잡제어 알고리즘

  • Hwang An-Kyu (Department of Information and Communications Engineering, Chungnam National University) ;
  • Lee Jae-Yong (Division of Electrical and Computer Engineering, Chungnam National University) ;
  • Jung Whoi-Jin (Department of Information and Communications Engineering, Chungnam National University) ;
  • Kim Byung-Chul (Division of Electrical and Computer Engineering, Chungnam National University)
  • 황안규 (충남대학교 정보통신공학과) ;
  • 이재용 (충남대학교 전기정보통신공학부) ;
  • 정회진 (충남대학교 정보통신공학과) ;
  • 김병철 (충남대학교 전기정보통신공학부)
  • Published : 2006.08.01
Download PDF
⟨ Previous Next ⟩

Abstract

With the widespread of the wireless Internet and wireless LAN, different wireless technologies such as 3G cellular networks and WLAN will cooperate to support more users and applications with higher data rate over wider areas. When a mobile node moves around in the hybrid networks, it needs to perform seamless vertical handoffs between different wireless networks to provide high performance data transmission. When an application with TCP connection in a mobile node performs a vertical handoff, TCP performance is degraded due to packet losses even though it maintains the previous TCP state information during handoff, because 3G and WLAN have different available bandwidth. In this paper, we propose a new congestion control algorithm for vertical handoff to improve the TCP performance by measuring the rough end-to-end available bandwidth and calculating the slow-start threshold. By ns-2 simulation, we show that the proposed algorithm enhances the TCP performance during vertical handoffs compared to the previous algorithms.

최근 무선 인터넷 및 WLAN이 활성화되면서 3G 이동 통신망과 WLAN망의 연동으로 보다 넓은 서비스 영역에서 높은 데이터 전송 속도를 제공하기 위한 연구가 활발하게 이루어지고 있다. 3G와 WLAN 연동망에서 이동 단말이 서로 다른 망으로 이동할 경우 높은 데이터 전송을 제공하기 위해서 끊김 없는 vertical handoff를 수행한다. 이동 단말이 TCP 연결 상태에서 vertical handoff를 수행하여 대역폭이 다른 망으로 이동할 경우 기존의 TCP 정보를 그대로 이용하면 3G와 WLAN 망간의 서로 다른 대역폭으로 인하여 패킷 손실이 발생하고 이로 인하여 TCP 성능이 낮아지게 된다. 본 논문은 vertical handoff를 통해 새로운 망으로 이동하였을 경우 사용 가능한 대역폭을 측정하여 TCP에 적용함으로써 TCP의 성능향상을 위한 새로운 혼잡제어 알고리즘을 제안하였고, ns-2 시뮬레이션을 통해 기존에 제안되었던 알고리즘보다 vertical handoff 시 TCP 성능이 향상됨을 보였다.

Keywords

References

  1. The Editors of IEEE 802.11. IEEE Standard for Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, ？Nov. 1997
  2. Wireless LAN Medium Access Control(MAC) and Physical Layer(PHY) Specifications, ANSV IEEE Std 802.11, Vol.1, 1999
  3. Wireless LAN Medium Access Control(MAC) and Physical Layer(PHY) Specifications, ANSV IEEE Std 802.11, Vol.2, 1999
  4. K. Thompson, G. J. Miller, R Wilder, 'WideArea Internet Traffic Patterns and Characteristics', IEEE Network, vol. 11, no. 6, pp. 10-23, Nov. 1997 https://doi.org/10.1109/65.642356
  5. G. Tim, M. James, Phatak. DS, G. Vipul, 'Freeze-TCP: A true end-to-end TCP enhancement-mechanism for mobile environments.', State University of New York, Sun Microsystem, INFOCOM 2000. vol. 3, pp. 1537-1545, Mar. 2003 https://doi.org/10.1109/INFCOM.2000.832552
  6. H. Balakrishnan, S. Seshan, and R.H. Katz, 'Improving reliable transport and handoff performance in cellual wireless networks.' ACM Wireless Networks, vol. 1., pp 469-481, Dec. 1995 https://doi.org/10.1007/BF01985757
  7. K. Brown, S. Singh, 'M-TCP : TCP for mobile cellular networks', ACM Computer Communications Review, vol. 27., pp 19-43, 1997 https://doi.org/10.1145/269790.269794
  8. M. Stemm, R. H. Katz, 'Vertical handoffs in wireless overlay networks,' ACM Mobile Networking and Applications (MONET), vol. 3, no. 4, pp. 335-350, 1998 https://doi.org/10.1023/A:1019197320544
  9. C. Perkins, 'IP Mobility Support for IPv4', IETF RFC 3220 (2002)
  10. S. Kim, J. Copeland, 'TCP for seamless vertical handoff in hybrid mobile data networks', in Proc. of IEEE GLOBECOM, San Francisco, vol. 2, pp. 661-665, Dec. 2003 https://doi.org/10.1109/GLOCOM.2003.1258321
  11. K. Xu, Y. Tian, and N. Ansari, 'TCP-Jersey for Wireless IP Communications, ' IEEE JSAC, vol. 22, no. 4, pp. 747-756, May. 2004 https://doi.org/10.1109/JSAC.2004.825989
  12. The Network Simulator ns-2, http://www.isi.edu/nsnam/ns