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Ad Hoc Wireless Networks

Ad Hoc Wireless Networks. Agenda. Ad Hoc Network Issues Power Conservation Approaches Routing Protocols Energy Conservation at the Network Layer. Ad hoc network.

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Ad Hoc Wireless Networks

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  1. Ad Hoc Wireless Networks 이동인터넷프로토콜

  2. Agenda • Ad Hoc Network • Issues • Power Conservation Approaches • Routing Protocols • Energy Conservation at the Network Layer 이동인터넷프로토콜

  3. Ad hoc network • A collection of two or more devices equipped with wireless communications and networking capability (Infrastructure-less Infrastructure) • Every node can forward packets • Self-organizing, adaptive • IETF WG • MANET (Mobile Ad hoc Network) • http://www.ietf.org/html.charters/manet-charter.html 이동인터넷프로토콜

  4. ● ● ● ● ■ ● ● ● BS ● ● ● Infrastructured network ad hoc network ● 유선으로 연결된 BS을 통하여 통신 이동단말기가 Router 역할 수행 Ad Hoc Network 이동인터넷프로토콜

  5. 이동인터넷프로토콜

  6. Ad Hoc Network • 3 Groups (G1, G2, G3) Ahas data to send to H Alooks for a route to H through G A finds the route 이동인터넷프로토콜

  7. Ad Hoc Network • Applications • Conferencing • Home Networking • Emergency Services • Personal Area Networks (PAN) and Bluetooth • Embedded Computing Applications (PDA etc.) • Sensor Networks 이동인터넷프로토콜

  8. Ad Hoc Network • Issues • Spectrum Allocation and Purchase • Media Access • Routing • Multicasting • Energy Efficiency • TCP Performance • Security & Privacy 이동인터넷프로토콜

  9. Protocol Layer Power Conservation Techniques • Data-Link Layer • MAC (Media Access Control) – IEEE802.11 • Network Layer • Routing Protocol • Transport Layer • TCP Performance 이동인터넷프로토콜

  10. Data-Link Layer • Avoid unnecessary retransmissions • Avoid collisions • Put receiver in standby mode whenever possible • Use/allocate contiguous slots for transmission and reception whenever possible • Turn radio off (sleep) when not transmitting or receiving 이동인터넷프로토콜

  11. Network Layer • Consider route relaying load • Consider battery life in route selection • Reduce frequency of sending control message • Optimize size of control headers • Efficient route reconfiguration techniques 이동인터넷프로토콜

  12. Transport Layer • Avoid repeated retransmissions • Handle packet loss in a localized manner • Use power-efficient error control schemes 이동인터넷프로토콜

  13. Routing • New routing protocols for Ad Hoc networks are needed • OSPF • Link-state protocol • High bandwidth required to maintain a current view of the network • RIP • Distance-vector algorithm • Very slow convergence (count to infinity) 이동인터넷프로토콜

  14. Ad Hoc Routing Protocols AD-HOC MOBILE ROUTING PROTOCOLS TABLE DRIVEN/ PROACTIVE ON-DEMAND-DRIVEN/REACTIVE HYBRID DSDV WRP CGSR STAR DSR ABR TORA AODV CBRP RDMAR ZRP 이동인터넷프로토콜

  15. Routing Protocols • Proactive (Table driven) • DSDV (Destination Sequenced Distance vector) • WRP (Wireless Routing Protocol) • CSGR (Cluster Switch Gateway Routing) • Reactive (On-demand-driven) • AODV (Ad Hoc On-Demand Distance Vector Routing) : RREQ, RREP • DSR (Dynamic Source Routing) – use cache • SSR (Signal Stability Routing) • PAR (Power-Aware Routing) • ABR (Associativity-Based Long Lived Routing) • Hybrid • ZRP (Zone Routing Protocol) 이동인터넷프로토콜

  16. DSDV • Destination Sequenced Distance Vector • Charles E. Perkins • Table-driven • Based on Bellman-Ford routing algo. • Full dump & incremental packet • Too many overhead for Ad hoc 이동인터넷프로토콜

  17. AODV • Ad Hoc On-Demand Distance Vector Routing • Charles E. Perkins, Elizabeth M. Royer • Improvement on DSDV • RREQ, RREP • Support only bidirectioinal link 이동인터넷프로토콜

  18. N2 N5 N8 Destination N1 Source N4 N7 N3 N6 AODV 이동인터넷프로토콜

  19. N2 N5 N8 Destination N1 Source N4 N7 N3 N6 Propagation of the RREQ AODV RREQ Broadcast Each node adds previous node to its routing table (to establish a reverse path) 이동인터넷프로토콜

  20. N2 N5 N8 Destination N1 Source N4 N7 N3 N6 Path of the RREP to the source AODV RREQ 이동인터넷프로토콜

  21. N2 N5 N8 Destination N1 Source N4 N7 N3 N6 AODV Data Sending Data 이동인터넷프로토콜

  22. DSR • Dynamic Source Routing • David B. Johnson (Carnegie-Mellon Univ.) • Two major phase • Route discovery • On cache misses • Route maintenance • Use cache -> Router Error packet (passive ack) • Support unidirectioinal links 이동인터넷프로토콜

  23. N2 N5 N8 Destination N1 Source N4 N7 N3 N6 DSR 이동인터넷프로토콜

  24. N2 N1-N2 N5 N1-N2-N5 N1 N8 Destination N1-N3-N4 N1 Source N4 N1-N3-N4 N1-N3-N4-N7 N7 N1-N3 N1 N1-N3-N4 N3 N1-N3-N4-N6 N6 Propagation of the RREQ DSR 이동인터넷프로토콜

  25. N2 N1-N2-N5-N8 N1-N2-N5-N8 N1-N2-N5-N8 N5 N8 Destination N1 Source N4 N7 N3 N6 Propagation of the route reply with the route record DSR 이동인터넷프로토콜

  26. N2 N5 N8 Destination N1 Source N4 N7 N3 N6 DSR Data Sending Data (by Source Routing) 이동인터넷프로토콜

  27. ABR • Associativity-Based Long Lived Routing • C-K Toh • Consider • Associativity Ticks/Counts • Link Delay • Signal Strength • Power Life • Route Relay Load 이동인터넷프로토콜

  28. ZRP • Zone Routing Protocol • Haas, Pearlman (Cornell University) • Proactive + Reactive • Intrazone (Routing Zone) -Proactive • IARP(Intrazone Routing protocol) • Interzone -Reactive • BRP(Bordercast Routing protocol) • IERP(Interzone Routing Protocol) 이동인터넷프로토콜

  29. Energy conservation Ad Hoc routing 이동인터넷프로토콜

  30. Geography-informed Energy Conservation for Ad Hoc Routing Ya Xu, John Heidemann, Deborah Estrin ACM/IEEE Mobicom2001 이동인터넷프로토콜

  31. Abstract • GAF • Geographical Adaptive Fidelity • Use application- and system-level info. • Independent of underlying ad hoc routing protocol (DSR, AODV) 이동인터넷프로토콜

  32. Introduction • Energy dissipation in idle state cannot be ignored • Routing fidelity • Uninterrupted connectivity between communication nodes • Employ location info (from GPS, etc.) 이동인터넷프로토콜

  33. Introduction 2 1 4 3 5 1 Nominal radio range 이동인터넷프로토콜

  34. Energy-conserving routing • Virtual grid • All nodes in a particular grid square are equivalent with respect to forwarding packets • For two adjacent grids A and B, all nodes in A can communicate with al nodes in B and vice versa • Based on the nominal radio range R 이동인터넷프로토콜

  35. Determining node equivalence 2 A B C 4 1 3 5 r r r 이동인터넷프로토콜

  36. GAF State Transition • Three states • Sleeping (Ts) • Discovery (Td) • Discovery message • node id, grid id, enat(estimated node active time) • Active (Ta) • Periodically re-broadcast its discovery msg at intervals Td 이동인터넷프로토콜

  37. GAF State Transition sleeping receive discovery msg from high rank nodes active after Ts after Td discovery after Ta 이동인터넷프로토콜

  38. Tuning GAF • enat (estimated node active time) • enlt/2 • enlt : time to use up all remaining energy • Td (discovery message interval) • A uniform random value between 0 and some constant • Ta • enat • Ts • Uniformly in [enat/2, enat] 이동인터넷프로토콜

  39. Tuning GAF • Node Ranking • Accorting to remaining energy level… 1. A node in active state has higher rank than a node in discovery state 2. For nodes with same state, GAF gives nodes with longer enat higher rank 이동인터넷프로토콜

  40. Adapting to high mobility • engt (expected node grid time) • In the discovery message • Ts < engt • engt = r/s • s : current speed of a node • GAF-b (basic) • GAF-ma (mobility adaption) 이동인터넷프로토콜

  41. Simulation • 50 mobile nodes • random waypoint model by Johnson, CMU • Speed : 0~1 m/s, 0~20 m/s • Nominal range : 250m • Area • 1500m x 300m • Pause times (0~900ms) • Traffic • CBR UDP • 1, 10, 20 pkts/sec by 10 traffic nodes 이동인터넷프로토콜

  42. Simulation • Energy Model • AT&T 2Mb/s WaveLAN • 1.6W for transmit • 1.2W for receiving • 1.0W for listening • 0.025W for sleeping 이동인터넷프로토콜

  43. Simulation In case of AODV, all nodes die out around 450ms!! Network lifetime comparisons : GAF-b vs. AODV at low node speed (1m/s) under various pause time. Movement : 1m/s, traffic : 20 pkts/s 이동인터넷프로토콜

  44. Simulation 이동인터넷프로토콜

  45. 이동인터넷프로토콜

  46. BECT: A Balanced Energy Consumption Algorithm by Threshold-Tuning for Mobile Ad Hoc Networks 2002. 11. 1 Real Time Internet Lab. Jaeho Chang 이동인터넷프로토콜

  47. Agenda • DSR • Dynamic Routing Protocol • BECT • DSR modification • Energy-Balancing by Threshold Tuning • Simulation • Conclusion & Future Work 이동인터넷프로토콜

  48. DSR • Dynamic Source Routing • Monarch Project (CMU) • http://www.monarch.cs.rice.edu • On-demand wireless Ad Hoc routing protocol • Source routing • Promiscuous mode (overhear), cache • Two major phase • Route discovery • RREQ, RREP msg • Route maintenance • On receiving RERR msg -> cache -> Route Discovery 이동인터넷프로토콜

  49. N2 N1-N2 N5 N1-N2-N5 N1 N8 Destination N1-N3-N4 N1 Source N4 N1-N3-N4 N1-N3-N4-N7 N7 N1-N3 N1 N1-N3-N4 N3 N1-N3-N4-N6 N6 Propagation of the RREQ DSR 이동인터넷프로토콜

  50. N2 N1-N2-N5-N8 N1-N2-N5-N8 N1-N2-N5-N8 N5 N8 Destination N1 Source N4 N7 N3 N6 Propagation of the route reply with the route record DSR 이동인터넷프로토콜

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