Mobile IPv6-based Efficient Vertical Handoff Approach for Heterogeneous Wireless Networks

1. Mobile IPv6-based Efficient Vertical Handoff Approach for Heterogeneous Wireless Networks Ben-Jye Chang Ph.D. (張本杰 博士) Department of Computer Science & Information Engineering Chaoyang University of Technology Taichung, Taiwan changb@mail.cyut.edu.tw NSC-93-2213-E-324-018

2. Outline • Introduction • Related Works • Motivations • Adaptive cost-based vertical handoff with predictive RSS • Numerical results • Conclusions

3. What is handoff? (Introduction) • Maintaining connections or communications when mobile node moves to other cell. • Advantages • Do not disconnect the original connections • Support Quality of Service (QoS) • Reduce cost • Disadvantages • (PS, CS) Extra handoff signaling and handshaking with new cell • (PS) Need Mobile IP for solving addressing issue

4. Heterogeneous Wireless Networks

5. Types of Handoff • Horizontal handoff • Moving to the network that with the same access network protocol • Vertical handoff • Moving to the network that with different access network protocols

6. Why needs Vertical Handoff ? • Two most popular networks • Cellular networks • Wireless LANs (i.e., WLANs) • Comparison between Cellular Networks and WLANs

7. What are the challenges to vertical handoff ? • Horizontal handoff algorithms are not suitable for vertical handoff • In VH, no comparable signal strengths associated with them • The roaming networks are hybrid networks • Ping-pong effect • High data rate • Mobile IP Issue • QoS mapping between two different protocols

8. Related Works • RSS-based handoff algorithm • RSS-Threshold (RSS-T) • 1. G.P. Pollini, “Trends in handover design,” IEEE Communications Magazine, Vol. 34, Issue 3, pp.82-90, March 1996.

9. Related Works (cont.) • RSS-based handoff algorithm • RSS-Hysteresis (RSS-H) • 2. N. Zhang, and J.M. Holtzman, “Analysis of handoff algorithms using both absolute and relative measurements,” IEEE Transactions on Vehicular Technology, Vol. 45, Issue 1, pp.174-179, Feb. 1996.

10. Related Works (cont.) • RSS-based handoff algorithm • RSS-Hysteresis with Threshold (RSS-HT) • 3. P. Marichamy, S. Chakrabarti, and S.L. Maskara, “Performance evaluation of handoff detection schemes,” TENCON 2003, Vol. 2, pp. 643 - 646, Oct. 2003.

11. Related Works (cont.) 4. K. Pahlavan, P. Krishnamurthy, A. Hatami, M. Ylianttila, J.P. Makela, R. Pichna, and J. Vallstron, “Handoff in hybrid mobile data networksfs,” IEEE Personal Communications, Vol. 7, Issue 2, pp. 34-47, April 2000. • RSS-T + Neural network-Based Algorithm 5. Hongyang Bing, Chen He, and Lingge Jiang, “Performance analysis of vertical handover in a UMTS-WLAN integrated network,” IEEE PIMRC 2003, Vol. 1, pp.187-191, Sept. 2003. • RSS + Distance (mobile – AP) 6. H.J. Wang, R.H. Katz, and J. Giese, “Policy-enabled handoffs across heterogeneous wireless networks,” IEEE Mobile Computing Systems and Applications Conference, pp. 51 - 60, Feb. 1999. 7. J. McNair and Zhu Fang, “Vertical handoffs in fourth-generation multinetwork environments,” IEEE Wireless Communications, Vol. 11, Issue 3, pp. 8-15, June 2004. • Cost function ( cost = ln (1/ bandwidth) )

12. Motivations • Propose an efficient VH algorithm for heterogeneous wireless networks • Minimize the number of vertical handoffs • Support QoS • Maximize network utilization • Minimize access cost

13. Adaptive Cost-based Vertical Handoff with Predictive RSS • Two-step approach • Predict RSS with hysteresis • Determine the optimal wireless network for handoffing

14. Hysteresiswith two-threshold Determine Optimal WLAN Determine Optimal WLAN + :Reducing the Ping-pong effect

15. 1. Predict RSS with hysteresis • Predictive algorithm • Advantages • Accurately catch the trend of RSS • Accurately predict RSS for making decision of VH

16. 2. Determine the optimal wireless network General function:

17. COL WLAN Cost Function • we adopt the COL (Competitive On-Line ) approach for defining WLAN cost • sets the WLAN cost as an exponential function of current residual bandwidth of the link • state-dependent cost function

18. WLAN Cost Function (cont.) • COL WLAN cost function, •  : a chosen constant parameter • Cap( ) : the capacity of WLAN n • COL WLAN cost for class k call, • The least cost WLAN will be selected as the optimal WLAN for vertical handoff

21. Mobile IPv6 Fast Vertical Handoff from 3G to WLAN

22. Mobile IPv6 Fast Vertical Handoff from WLAN to 3G

23. Numerical results • Simulation Parameters • Performance Metrics • Numerical results

24. Simulation Parameters

25. Performance Metrics • The number of vertical handoffs • Dropping probability • Network throughput

26. The number of vertical handoffsunder different arrival rate(NDS=50, APS=10) smooth congestion

27. Dropping probability under diff. arrv.(NDS=50, APS=10) No dropping smooth congestion

28. Network throughputunder diffent arrv. (NDS=50, APS=10) Closely smooth congestion

29. The number of vertical handoffs under various mobilities(NDS=50, APS=10) slow fast

30. Dropping probability under various mobilities (NDS=50, APS=10) No dropping slow fast

31. Network throughput under various mobilities (NDS=50, APS=10) Closely fast slow

32. The number of vertical handoffs under different NDS (APS=10, λ=10)

33. Dropping probability under different NDS (APS=10, λ=10) No dropping

34. Network throughput under different NDS (APS=10, λ=10) Closely

35. Conclusions • we proposed an adaptive cost-based with predictive RSS vertical handoff approach to determine the optimal wireless network for handoff in heterogeneous wireless networks. • A two-phase procedure • The predictive RSS with hysteresis phase • The determination of optimal wireless network phase • The proposed approach outperforms other approaches in • The least number of vertical handoffs while yielding competitive throughput • Yielding none dropping probability, which meets the characteristic of an optimal vertical handoff in heterogeneous wireless networks.

36. Q & AThanks changb@mail.cyut.edu.tw

37. Horizontal handoff Receives B1 & B2 signal In cell B1 RSS_B2>RSS_B1,Switches to cell B2

38. Vertical handoff In 3G, receives AP signal In 3G VHO Determine Algorithm.Switches to WLAN In WLAN