Thesis Author: Shan Gong Supervisor: Sven-Gustav Häggman

1. S-72.158 Master’s thesis seminar 8th August 2006QUALITY OF SERVICE AWARE ROUTING PROTOCOLS IN MOBILE AD HOC NETWORKS Thesis Author: Shan Gong Supervisor: Sven-Gustav Häggman

2. Outlines • Ad Hoc Networks • QoS (Challenge of implementing QoS in ad hoc networks, QoS metrics, QoS metric calculation) • AODV • Access admission control in QAODV • QAODV • Simulation Environment and Results

3. Mobile Ad hoc networks • The application of mobile ad hoc networks becomes more and more popular. • Applications of Mobile Ad Hoc Networks (Military Applications, Emergency Operations, Wireless Mesh networks, Wireless sensor networks).

4. QoS • “Quality of Service is the performance level of a service offered by the network to the user”. • QoS considered in this thesis work: low end to end delay (e.g. real time traffics)

5. Challenge of QoS in ad hoc networks • Dynamically varying network topology • Lack of precise state information • Shared radio channel • The resources such as data rate, battery life, and storage space are all very limited in ad hoc networks.

6. QoS metrics • Additive metrics (end to end delay) • Concave metrics (data rate) • Multiplicative metrics. (link outage probability) • The generally used metrics for real time applications are data rate, delay, delay variance (jitter), and packet loss.

7. Calculation for locally available data rateMethod 1: Transmission range = Carrier sensing range Case 1 is the data rate used by node i for receiving data. Case 2 is the data rate consumed by neighbors who are receiving. Case 3 is the data rate consumed by neighbors who are sending.

8. Calculation for local available data rateMethod 2: Carrier sensing range is more than twice of the transmission range (more realistic)Data Rate =(N*S*8)/T The used data rate is the sum of the sent, received and sensed data rate

9. AODV routing protocol • Reactive • RREQ (broadcast) and RREP (unicast) • RERR

10. Access Admission ControlAvailable bandwidth ? Required bandwidth

11. A B C D E Required data rate at each nodeMethod 1 carrier sensing range = transmission rangeWith a N-hop route, the source and destination nodes should satisfy ABi>=2r, the second and N-1 nodes ABi >=3r and the intermediate nodes ABi >=4r. Here, r is the required data rate requirement and ABi is the available data rate at node i. N-1 node is the node on the path which is next to the destination node.

12. Required data rate at each node Method 2 carrier sensing range >= 2* transmission range • The contention count is calculated as follows • If hreq > 2  hreq = 2 otherwise hreq=hreq • If hrep > 3  hrep = 3 otherwise hrep=hrep • CC = hreq + hrep

13. 2 6 1 5 7 3 4 Required data rate at each node Method 2 carrier sensing range >= 2* transmission rangeExample

14. Maximum data rate Vs. Hops of a route

15. QAODV routing protocol-draft • Session ID • Maximum delay extension field • Minimum data rate extension field Node satisfying these requests could broadcast the RREQ further • List of sources requesting QoS guarantees

16. Broadcast RREQ Enough Data rate? Recv RREQ Drop RREQ Forward RREP Enough Data rate? Recv RREP Drop RREP Do nothing Available data rate >0 Periodically check Available Data rate Send ICMP_QoS_Lost Forward ICMP_QoS Lost Whether I am the source node Recv ICMP_QoS_ Lost Stop traffic AODV vs. QAODV

17. 550 m (Interference range) Move direction of Node 3 1 3 3 3 150 m Traffic stopped 2 0 600 m Example for QAODV—periodic check for available data rate

18. Scenario

19. Simulations with both AODV and QAODV

20. Performance metrics • Average end to end delay • Packet Delivery Ratio (PDR) • Normalized Overhead Load (NOL) • Route finding time of the first route

21. Simulation Environment • The channel type is “wireless channel” • radio propagation model is “two ray ground”. • MAC layer based on CSMA/CA as in IEEE 802.11 is used with RTS/CTS mechanism. • The data rate at physical layer is 11 Mbps. • Queue type is “drop tail” • the maximum queue length is 50. • Routing protocols are the AODV and the QAODV. • The transmission range and carrier sensing range are 250 m and 550 m respectively.

22. Specific Scenarios for Simulations. • The area size is 700 m * 700 m • 20 nodes in this area. • Every experiment will be run 1000 s in total. (500 s is added at the beginning of each simulation to stabilize the mobility model.) • Each data point in the results represents an average of 10 trails with same traffic model but different randomly mobility scenarios. • For fairness comparisons, same mobility and traffic scenarios are used in both the AODV and the QAODV routing protocols. • In the following set of simulations, a group of data rates ranging from 50 kbps to 1800 kbps is applied. • The mobility scenario is with a pause time of 10 seconds and the maximum node speed of nodes is 1 m/s.

23. Traffic pattern

24. Average end to end delay

25. Packet Delivery Ratio

26. Normalized Overhead Load

27. The first traffic flow 553 s ~ 774 s. The second traffic flow 680 s ~ 780 s. Time used to find the first route

28. Summary and Conclusions • QAODV outperforms AODV in terms of end to end delay • Constrain the packets which might be useless to the network • More routing packets are sent (brings problem when node density is high) • More QoS metrics could be added to the routing protocol (delay, packet loss)

29. Thank you