1. DRP: An Efficient Directional Routing Protocol for Mobile Ad Hoc Networks Hrishikesh Gossain Mesh Networks Product Group, Motorola Tarun Joshi, Dharma P. Agrawal Department of ECECS, University of Cincinnati Carlos Cordeiro Philips Research IEEE Transactions on Parallel and Distributed Systems(TPDS), December 2006 Note: This material is borrowed from Morris Chang

2. Outline  Introduction  Directional Routing Protocol(DRP) MAC Routing  Performance Evaluation  Conclusions

3. Introduction --- Antenna Model A Directional modeOmni mode B  Benefits of directionality Spatial reuse Higher transmission range

4. Introduction --- Antenna Model  A switched beam directional antenna system Omni mode  used only to receive signals Directional mode  used for both transmission as well as reception

5. Introduction --- Antenna Model  Data transmission  Receiver stay omni mode B F RTSCTSDATAACK

6. Introduction --- Problems  After Node X has a successful DATA transmission to Y, Y forwards data to Z  Hidden terminal problems X’s RTS collides with Y’s RTS  Deafness problems X’s RTS will fail

7. Introduction --- Motivation and Goals  Motivation Establishment and maintenance of directional routing path  Goals Minimizing the effect of deafness and hidden terminal problem Reduce control overhead of routing

8. DRP --- overview  Inspired by omnidirectional Dynamic Source Routing (DSR)  Assume know neighbors’ location

9. DRP --- MAC  Diametrically Opposite Directional (DOD) RTS and CTS  Avoid to a high number of collisions of RTS and CTS  Reduce delay

10. DRP --- MAC  Enhanced Directional NAV (EDNAV) The node is not to lie within the communication path of the oncoming transmission Increase concurrent transmission DATA DODRTS

11. DRP --- Routing  Route Discovery Flood a RREQ packet Reduce packet redundancy Rebroadcast only in beams 1, 0, 2, 7, and 3 in that order

12. DRP --- Routing  Send the RREP RREP DATA

13. DRP --- Route maintenance  Case 1:the movements of a nexthop within the range Nexthop is accessible through a different antenna beam  Case 2: the nexthop has moved out of the range Case 1 Case 2

14. DRP --- Location Tracking Phase  If the transmission of an RTS from X to Y’s previous location (say antenna beam “i”) fails for 3 consecutive attempts  Node X tries to locate Y in its adjacent antenna beams for the remaining tries Range of Connectivity

15. DRP --- Two-Hop Directional Local Recovery Phase  After detecting a broken link to Y, node X identifies the second nexthop in its path  Node X generates a directional RREQ packet to find the route to Z with maximum propagation limit set to 2  Used Route Error (RERR) packet to convey route update information to the source

16. Simulation  NS2 Simulator  The transmission range Omnidirectional: 250 4 beam directional antenna: 370 8 beam directional antenna: 550 12 beam directional antenna: 710  A square grid of 64 nodes with internode spacing set to 250 meters

17. Simulation --- Route Discovery Latency

18. Simulation --- Directional Broadcast Overhead

19. Simulation --- Hop Length  5 different source-destination pairs

20. Simulation --- Throughput 2 parallel flows

21. Simulation --- DRP Location Tracking

22. Simulation --- Local route recovery Packet Delivery Ratio

23. Conclusions  Propose a cross layered directional routing prtocol(DRP) Reduce control overhead of routing Increase routing throughput

24. Thank you