1. Track-based Hybrid Service Discovery in Mobile Ad-hoc Networks Zhuoqun Li, Lingfen Sun and Emmanuel C. Ifeachor School of Computing, Communications and Electronics University of Plymouth, UK

2. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany2 Presentation Outline Introduction Related work The track-based service discovery Simulation settings and performance evaluation Conclusion

3. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany3 Introduction: Service discovery in mobile ad-hoc networks -- an eHealchcare emergency scenario Where’s the ECG analyser? I can analyse ECG signals.

4. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany4 The aims Efficiency, i.e. minimal bandwidth overhead Accuracy, i.e. Maximal success rate The challenges of service discovery in Mobile ad-hoc networks The situation Without a central infrastructure Without a central infrastructure Unstable topology Unstable topology Limited resource Limited resource

5. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany5 Virtual Backbone  constant proactive overhead  Susceptible to single node failures Pure Reactive  Heavy querying overhead Hybrid (Zone-based)  Constant overhead for the proactive “zones”  Sensitive to mobility and network size Previous Work

6. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany6 Instances of proactive areas in the Zone-based and Track- based Hybrid Service Discovery : A B D E F G C Zone-based service discovery A B D E F G C Track- based service discovery Service consumer/providers Nodes that are involved in a proactive zone/track Other nodes

7. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany7 The track-based service discovery: s tep by step A B D E F G C the process of service discovery between service consumer B to service provider F Periodical Validation Reactive discovery/reply Path

8. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany8 Simulation Model ns-2 simulator 20 to 120 nodes 700m x 700m to 1800m x 1800m of simulation area 250m radio range IEEE 802.11b MAC; 2Mbps data rate Random-Waypoint Mobility Model default discovery pattern is T(12,1),  i.e. each of 12 service consumers initiates 1 query per second Protocols in comparison: “Flooding”, “Track” and “Bordercasting”

9. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany9 Performance Evaluation: Querying overhead vs. mobility and network size

10. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany10 Performance Evaluation: Control packets overhead vs. mobility and network size

11. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany11 Performance Evaluation: First attempt success rate vs. mobility and network size

12. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany12 Conclusion We present the novel track-based scheme for service discovery in mobile ad-hoc networks.  the structure of proactive areas are one dimensional  the density of proactive areas (tracks) is adapted to traffic patterns In comparison to the pure reactive and Zone-based schemes, preliminary results show that the track-based scheme  requires minimal (proactive and reactive) overhead proactive  optimal trade-off between the overhead and success rate of service discovery

13. IEEE PIMRC 11 - 14, Sep. 2005, Berlin, Germany13 Thank You! http://www.tech.plym.ac.uk/spmc/ http://www.biopattern.org Related Website: The Signal Processing & Multimedia Communications Group, University of Plymouth, UK The EU FP6 Network of Excellence Project BIOPATTERN