Yi-Ying Liao Ju-lan Hsu

1. EE206A Class Project --A Joint MAC and Routing Protocol for Wireless Ad Hoc Network with Directional Antennas Yi-Ying Liao Ju-lan Hsu

2. Introduction • The advantage of using directional antenna

3. Related work with directional antenna • MAC • Spatial reuse / power consumption • Hidden terminal problem • Routing • Spatial reuse • How to do traffic-aware routing?

4. Routing with directional antenna • Use MAC to perceive and communicate with the traffic information • According to the traffic pattern, new traffic is routed to balance out and avoid contention (use disjoint paths)

5. System description • Ad Hoc wireless multihop networks • Every node is equipped with identical antenna array • Channel is symmetric and bi-directional

6. Antenna model • Switch beam antenna with M elements • Directional mode / omni-directional mode • Same range • AOA (angle-of-arrival) catching

7. A B Nodes in this region may interfere DATA Nodes in this region may interfere ACK Proposed Algorithm –MAC layer • Directional RTS-CTS-DATA-ACK handshaking • Solve hidden terminal problem • A’s neighbor unaware of A’s transmission

8. ID Neighbor Beam number timer Cont. • AOA caching • Flooding when local AOA changes • Active node list (ANL) table • Broadcast every T seconds • AOA is updated using ANL broadcasting

9. Cont. • Directional NAV • Directional RTS / Omni RTS defer

10. My ID Seq. ID Active Recency NodeA NodeB .. .. Routing • Source routing algorithm • Every node keeps 2 tables • Active node list (ANL) table • Link state table (LST)

11. Active node list • Contains keeper’s perception about communication activities in the network • Periodically broadcast • On receiving neighbors ANLs, nodes update its own ANL • When a RTS-CTS handshake is successful, transmitter and receiver set themselves as active nodes

12. Node Beam1 Beam2 BeamM 1 4,5, .. 2,7,3 2 1 8,5 Link state table • Contains keeper’s perception about the network topology information • Established by AOA table flooding in the beginning • When a node’s AOA changes, floods again

13. Routing scheme • Use LST to construct the graph representing network topology • The weight of a link = how much congestion it will cause to use this link • Choose the shortest path as route => minimum interference route

14. Weight assign Sn,B = set of nodes that can be reached by Bth beam of node n SANL = set of nodes in the ANL T = Sn,B  SANL For n =1 to N For B = 1 to M { if T !=  for s  Sn,B w(ns) = | T | } }

15. Simulation • 8 switched beams directional antenna, each with an angle of 45 degrees

16. MAC layer simulation • 33 nodes are randomly placed • 16 CBR sources are randomly chosen; destinations are randomly chosen from each source’s neighbors • Simulation time is 600s • Compared with 802.11

19. Routing + MAC • 27 nodes are randomly placed • 6 CBR source and destination pairs are randomly chosen • Simulation time is 30s • Compared with directional 802.11+AODV • ANL periodicity T =2s, ANL size = 24bytes

22. Discussion • Routes need to be adaptively modified in the intermediate nodes if mobility is considered. This can be done by recalculate the shortest path during packets travel along

23. References [1] M.Takai, J.Martin, A.Ren, R. Bagrodia, Directional Virtual Carrier Sensing for Directional Antennas in Mobile Ad Hoc Networks, ACM MobiHoc, June 2002 [2] Thanasis Korakis, Gentian Jakllari, Leandros Tassiulas, A MAC Protocol for Full Exploitation of Directional Antennas in Ad-Hoc Wireless Networks, ACM MobiHoc, June 2003 [3] R.Ramanathan, On the Performance of Ad Hoc Networks with Beamforming Antennas, ACM MobiHoc, October 2001 [4] S. Bandyopadhyay, D. Saha, S. Roy, T. Ueda, A Network-Aware MAC and Routing Protocol for Effective Load Balancing in Ad Hoc Wireless Networks with Directional Antenna, MobiHoc 2003 [5] N. Vaidya, Y.b. Ko, and V. Shankarkumar, Medium Access Control Protocols for Directional Antennas in Ad Hoc Networks, INFOCOM 2000