Mechanical Transport of Bits - Part II

1. Mechanical Transport of Bits - Part II Jue Wang and Runhe Zhang EE206A In-class presentation May 5, 2004

2. Outline • A Message Ferrying Approach for Data Delivery in Sparse Mobile Ad Hoc Networks (MobiHoc 2004) W. Zhao et al. • Intelligent Fluid Infrastructure for Embedded Networks (MobiSys 2004) A. Kansal et al.

3. Sparse MANET • What is Sparse MANET? • What are the challenges for Sparse MANET? • What are the solutions? • Extending transmission range • Store – carry – forward • Reactive vs Proactive

4. Related Work • Ad Hoc Network Routing: • DSR, DSDV, AODV, GPRS, ZRP, LAR, CEDAR • Ad Hoc Network Routing for Sparse Networks (in detail next slide) • Capacity of Wireless Network • Gupta and Kumar • Grossglauser and Tse • Topology Control

5. Related Work:sparse – MANET • Infostation: (Goodman et al): High bit rate connection, geographically distributed, discrete coverage • DataMule: (Shah et al): Static sensor nodes, controllable mobile entities to ‘move’ data • DTN: (Fall et al): no control over the network, nodes stay there, hope for the best • Range extension (Ahmed et al): increase range to overcome the partitions • SWIM (Small and Hass): combines infostation and ad hoc networking architecture (has been presented – Whale)

6. Sparse – MANET (cont.) • Mobility assisted: Proactive, Reactive • Epidemic routing: (Vahdat et al) Flooding (pros: robustness, cons: redundant messages) • Mobile Relay Protocol: (Nain et al) take advantage of node mobility to overcome message delivery • Actively modify trajectories to transmit as soon as possible (hard to have multiple transmission simultaneously)

7. Message Ferrying (MF) • Proposed in this paper • Two different types: • Node-Initiated MF (NIMF) • Ferries move around the deployed area according to known routes and communicate with other nodes they meet. With knowledge of ferry routes, nodes periodically move close to a ferry and communicate with the ferry. • Ferry-Initiated MF (FIMF) • Ferries move proactively to meet the nodes. When a node wants to send packets to other nodes, it generates a service request and transmits it to a chosen ferry using long range radio. Upon reception of a service requests, the ferry will adjust its trajectory to meet up with the nodes.

8. Node-initiated Msg Ferrying

9. NIMF – node operation

10. NIMF – Ferry Operation

11. FIMF – node operation

12. FIMF – Ferry Operation

13. Performances • NS: Network Simulator • 802.11 with 250m communication range • 5000x5000m – make sparse • 40 nodes, Random Waypoint Models • Single Ferry, 15m/s, buffer size 400 message, route: rectangle with (1250,1250), (3750,3750) as diagonal pts. • 25 nodes chose to send message every 20 seconds

14. Performance: Impact of Buffer Size

15. Performance: Impact of mobility pattern

16. Performance: FIMF: impact of transmission range

17. Application • Crisis Driven • Battlefield and disaster applications • Geography Driven • Wide area sensing and surveillance app. • Cost Driven • Service Driven

18. Conclusion • Sparse network • Solution: Proactive vs Reactive • Proposal: two schemes for message ferry • Simulation results.

19. Intelligent Fluid Infrastructure for Embedded Networks A. Kansal et al. (MobiSys 2004)

20. What is the paper talk about? • Use of external mobility for improving network performance. • External mobility: Controllable mobility – autonomous mobile router • Network: Sensor Network

21. Type of Mobility • Random Mobility • Increase capacity (Grossglauser and Tse) • Application: Whale, Zebranet • Problem: Unbounded Delay • Predictable Mobility • Chakrabarty et al. (commuter bus model) • Problem: Usually mobility pattern is not predictable • Controlled Mobility • This paper: External mobility – (for ecological or habitat researches, no free mobile components, these mobiles may be limited in capacity, maneuverability, etc.) • Another application: DTN

22. Advantages using controlled mobility – 1 • Increased system life time. • How? In paper: Reducing the packet sent (relays – fewer hops) - reducing energy consumption. • More: when you reduce the hop count, you increase the spatial reuse, you also increase the throughput

23. Advantages using controlled mobility – 1 – Simulation

24. Advantages using controlled mobility – 2 • Data Fidelity • The less hop it is, the less probability of error it occurs. • Increase quality of received data, decrease the number of retransmission.

25. Advantages using controlled mobility – 3

26. Advantages using controlled mobility – 3 • Reduced latency • No mobile router case:Tideal=T(A,A,B)+T(A,B,Base)+T(B,B,Base) • Mobile router case:Tmobile=D(Base,A)+T(A,A,MR)+ D(A,B)+T(B,B,MR)+D(B,Base)+ T({A,B},MR,base)

27. Advantages using controlled mobility – 4 and others • Sparse and disconnected Networks • Reduced communication range • Reduced energy consumption • Less hop counts, easier synchro-nization • Security • Localization

28. Processing Platform • Stargate xScale • 802.11 cards • Motes • Packbot (60W)

29. Adaptive Motion Control - Constraint • Energy limitations • Terrain constraints • Disturbances, noises • Environment constraints

30. Adaptive Motion Control - Objective • Maximize the lifetime of the system • Maximize the total amount of data collected • Minimize the data transfer delay • Minimize the buffer size • Minimize the recharge time? • Formulate as Optimization Problem?

31. Influence of speed of data collection • No effect onpackets/second

32. Latency Sensitive Data Collection • SCD: Stop to Collectdata • Stop at locationswhere static nodes are found waiting with data

33. Latency Sensitive Data Collection • ASC: Adaptive Speed Control • Move slower in regions where data collection is moderately poor and stop in regions where data loss is severe. • N1: nodes with low delivery % • N2: nodes with high delivery % • T: round traversal time • Delta = T/2 * 1/(n1+n2/2) • SL : encounter of node type N2 • ST : encounter of node type N1 • TE : current time timer expired • Sigma : duration which a timer is reset

34. Latency Sensitive Data Collection

35. Latency Sensitive Communication in sparse networks • Propose to use SCD algorithm

36. Experimental Results – 1

37. Experimental Results – 2

38. Experimental Results – 3

39. Conclusion and Future Works • Controllable Mobility introduced • Advantages for using mobile router • 2 Strategies for moving 1 mobile router • Collaboration between mobile routers • Scenarios where the sensor nodes are moving themselves – MANET

40. Thank you!