1. CSR: Cooperative Source Routing Using Virtual MISO in Wireless Ad hoc Networks IEEE WCNC 2011 Yang Guan, Yao Xiao, Chien-Chung Shen and Leonard Cimini Speaker: Wun-Cheng Li

2. Outline Introduction Goal Cooperative Source Routing (CSR) ▫ Building SISO Network Topology ▫ Cooperative RREQ Transmission ▫ Selecting Relay Nodes to Forward RREQs ▫ Feedbacking RREP to Source ▫ Transmitting Data Packets Performance evaluation Conclusion 2

3. Introduction To improve the spectrum efficiency and link reliability of wireless communications ▫ space-time communications Simultaneously transmitted at the source and received at the destination by multi-antenna arrays ▫ improve the performance 3

4. Introduction Multiple-input single-output (MISO) systems on a single node can improve signal quality ▫ Limited physical size ▫ Cost constraints 4

5. Introduction Cooperative Transmissions ▫ Virtual antenna array  Improve signal quality  Enhance the performance of both throughput and energy- efficiency 5

6. Introduction Compared to the single-input single-output (SISO) link ▫ Virtual MISO link can achieve diversity gain ▫ Reflect into a decrease in the reception threshold at the receiver 6

7. Dynamic Source Routing (DSR) ▫ route request (RREQ) Related Work DSR 7 S A B C D RREQ:S RREQ:S, A RREQ:S, A, C

8. Dynamic Source Routing (DSR) ▫ route request (RREQ) ▫ route reply (RREP) Related Work DSR 8 S A B C D RREP:D RREP:D, C RREP:D, C, A

9. Dynamic Source Routing (DSR) ▫ route request (RREQ) ▫ route reply (RREP) Then specific nodes along the primary route are selected to establish VMISO links. Related Work DSR 9

10. The quality of VMISO links highly depends on the primary SISO route discovered. Problem 10

11. Goal The cooperative gains can be utilized to improve network performance ▫ lower end-to-end delay ▫ higher route discovery success ratio 11

12. Cooperative Source Routing (CSR) Building SISO Network Topology ▫ The neighbor update messages build up a SISO network topology (SNT) ▫ Periodically broadcasts a neighbor update message 12 C D B A

13. Cooperative Source Routing (CSR) Cooperative RREQ Transmission 13 P C M Q D K S T E B JL AOFR C D B pilot tones local RREQ Cooperative RREQ Transmission

14. Cooperative Source Routing (CSR) Selecting Relay Nodes to Forward RREQs 14 r is a random variable between 0 and 1 d is a candidate node’s SISO hop count to the destination C is the maximum time to transmit one cooperative RREQ is set to be 8 to avoid extra energy consumption is set to be the total time for a RREQ to traverse from a source to a destination with 20 cooperative RREQ forwarding steps

15. Cooperative Source Routing (CSR) Selecting Relay Nodes to Forward RREQs 15 P C M Q D K S T E B JL AOFR

16. Cooperative Source Routing (CSR) Feedbacking RREP to Source 16 P C M Q D K S T E B JL AOFR ?

17. Cooperative Source Routing (CSR) Feedbacking RREP to Source 17 P C M Q D K S T E B JL AOFR

18. Cooperative Source Routing (CSR) Transmitting Data Packets 18 P C M Q D K S T E B JL AOFR C D B M K J L Data

19. Cooperative Source Routing (CSR) Transmitting Data Packets ▫ receive an acknowledgement have certain time threshold 19 P C M Q D K S T E B JL AOFR M K J L S T ACK

20. Performance evaluation QualNet 3.7 20 Parameter Settings Randomly rectangular terrain1000m × 1000m Nodes15 or randomly message size1024 bytes transport layer protocolUDP scenario is simulated500 trials Controlled network topology

21. Performance evaluation 21

22. Performance evaluation 22

23. Performance evaluation 23

24. Conclusions This paper proposed cooperative source routing (CSR) protocol to better exploits the cooperative gain facilitated. Simulations results show that CSR facilitates higher route discovery success ratio and low end-to-end delay. 24

25. Thank you! 25