1. System Study of the Wireless Multimedia Ad-hoc Network based on IEEE 802.11g Authors Chung-Wei Lee Jonathan C.L. Liu & Kun Chen Yu-Chee Tseng & S.P. Kuo Presented by Nandita Uppalapati Deepthi Thanigundala 1

2. System Study of the Wireless Multimedia Ad- hoc Network based on IEEE 802.11g 1) Introduction 2) Related work 3) Experiments 3-1) Indoor without obstructions 3-2) Outdoor without obstructions 3-3) Penetrating wall 4) Results and Analysis 4-1) Indoor without obstructions 4-2) Outdoor without obstructions 4-3) Penetrating wall 5) Proposed Schemes and Protocols 6) Large scale simulations 7) Conclusions 2

3. 3 1. Introduction

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5. Introduction High Bandwidth: -54 Mbps 802.11g is used to replace 11Mbps 802.11b networks Working in mixed environments: -Obtain baseline performance with different conditions like in Indoors – walls, ceiling, desks, chairs which scatter the signal Outdoors – natural obstacles and humidity, temperature moving objects like people, cars ->signals tend to propagate like water ripples 5

6. Adhoc Network 6

7. Software Benchmarking For multi-media applications -Environmental effects should be considered Wireless environment -Higher error rates for data transmission => average performance at the users end. Software emulates constant streaming of multimedia data between two hosts. 7

8. Observations Conventionally, bandwidth of the ad-hoc networks is usually large when distance between the laptops is less. But that is not the case always. - Indoor: Worst performance within 5meters. UDP outperformed TCP up to 38.5% in achieved bandwidth.

9. Observations-contd - Outdoor: TCP favors short distance (5meters) or long distance (25meters) UDP was best at 10meters - Wall penetration: Routing nodes within 5meters. else overall bandwidth reduces significantly.

10. Proposed Algorithm  Proposed MaxThroughput algorithm to find paths with sufficient bandwidth guarantee  Result - better path - bandwidth about 30% higher than conventional methods even though, node number is small and path selection is limited 10

11. System Study of the Wireless Multimedia Ad- hoc Network based on IEEE 802.11g 1) Introduction 2) Related work 3) Experiments 3-1) Indoor without obstructions 3-2) Outdoor without obstructions 3-3) Penetrating wall 4) Results and Analysis 4-1) Indoor without obstructions 4-2) Outdoor without obstructions 4-3) Penetrating wall 5) Proposed Schemes and Protocols 6) Large scale simulations 7) Conclusions 11

12. Related Work Finding optimal solution satisfying multiple QoS is NP- complete. Distance factor was not considered in any of the previous studies. 12

13. System Study of the Wireless Multimedia Ad- hoc Network based on IEEE 802.11g 1) Introduction 2) Related work 3) Experiments 3-1) Indoor without obstructions 3-2) Outdoor without obstructions 3-3) Penetrating wall 4) Results and Analysis 4-1) Indoor without obstructions 4-2) Outdoor without obstructions 4-3) Penetrating wall 5) Proposed Schemes and Protocols 6) Large scale simulations 7) Conclusions 13

14. 3. Experiments Hardware required: - Laptop computers with Pentium IV processor, 512 M memory, 40G hard disk - Two identical wireless adapters - Linksys 802.11g wireless cards use 2.4-GHz frequency (bandwidth up to 54Mbps), mode set to ad-hoc mode and number of channel is set to six - Subnet mask = 255.255.255.0, gateway function disabled Software required: - Windows XP operating system - Benchmarking software on top of the TCP/UDP/IP protocols  Benchmarking software discards top 2.5% and bottom 2.5% of the measured results => only 95% interval of the average performance is represented 14

15. Indoor without obstructions 15 Location : Computer and Information Science Engineering basement building in order to minimize interference of access point of the infrastructure wireless connections Experiment at three different distances -TCP, UDP – 5meter - TCP, UDP – between 5 and 10 meters - TCP, UDP – between 10 and 20 meters

16. Outdoor without obstructions Location : Parking lot at VA hospital Less cars parked far away, in order to minimize interference of cars Experiment done at similar distances as that of Indoor 5meters, 5 and 10meters, 10 and 20meters 16

17. Penetrating wall 17 Location : New Physics building basement in order to minimize interference Laptop inside the building is fixed and the one which is outside the building is moved to maintain distance between them Experiment at three different distances -TCP, UDP – 5meter - TCP, UDP – between 5 and 10 meters - TCP, UDP – between 10 and 20 meters

18. System Study of the Wireless Multimedia Ad- hoc Network based on IEEE 802.11g 1) Introduction 2) Related work 3) Experiments 3-1) Indoor without obstructions 3-2) Outdoor without obstructions 3-3) Penetrating wall 4) Results and Analysis 4-1) Indoor without obstructions 4-2) Outdoor without obstructions 4-3) Penetrating wall 5) Proposed Schemes and Protocols 6) Large scale simulations 7) Conclusions 18

19. 4. Results and Analysis 19 Increase in the size of messages resulted in increased throughput Indoor TCP Throughput Results-Indoor conditions

20. Ad-hoc mode performs worst with the distance < 5meters Increasing distance improves throughput Reason? - Multi-path propagation of radio frequency 20

21. Results-Indoor conditions 21 Increase in unit size => throughput for UDP increased UDP protocol stack reduces headers and overhead => throughput performance increases significantly Peak average throughput = 18Mbps 38.5 % improvement Unit Size influence, UDP

22. UDP 22 Indoor UDP Throughput Results-Indoor conditions

23. Results-Outdoor without Obstructions 23 Outdoor TCP Throughput

24. Results-Outdoor without Obstructions As the experiment was performed on-campus, some factors were eliminated Multi-path interference has less effect TCP protocol best – 5 or 25 meters worst – 20 meters 24

25. 25 Output UDP Throughput Results-Outdoor without Obstructions

26. Performance improved to 19.1 Mbps, message size = 2Mbyte Best performance @ 10 meters If message size > 256 Kbytes, distance has limited impact on achieved bandwidth 26

27. 27 TCP Penetrating Walls Results-Penetrating Walls

28. 28 Results-Penetrating Walls UDP

29. System Study of the Wireless Multimedia Ad- hoc Network based on IEEE 802.11g 1) Introduction 2) Related work 3) Experiments 3-1) Indoor without obstructions 3-2) Outdoor without obstructions 3-3) Penetrating wall 4) Results and Analysis 4-1) Indoor without obstructions 4-2) Outdoor without obstructions 4-3) Penetrating wall 5) Proposed Schemes and Protocols 6) Large scale simulations 7) Conclusions 29

30. Proposed Schemes and Protocols Algorithm RandomTopology(n) Algorithm MinHop(u) Algorithm MaxThroughput(u)

31. Notation: - bw(i,j): link bandwidth as a function of physical distance - H(v): current hop count from the source node u to destination v - B(v): current path bandwidth from the source node u to destination v - N: the set contains all nodes in a topology - N’: a subset of N 31

32. Algorithm RandomTopology(n) 32

33. Algorithm MinHop(u) 33

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35. System Study of the Wireless Multimedia Ad- hoc Network based on IEEE 802.11g 1) Introduction 2) Related work 3) Experiments 3-1) Indoor without obstructions 3-2) Outdoor without obstructions 3-3) Penetrating wall 4) Results and Analysis 4-1) Indoor without obstructions 4-2) Outdoor without obstructions 4-3) Penetrating wall 5) Proposed Schemes and Protocols 6) Large scale simulations 7) Conclusions 35

36. Large Scale Simulations Experiments designed to handle 300meters x 300 meters area MinHop routing MaxThroughput UDP 36

37. Large Scale Simulations 37

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40. System Study of the Wireless Multimedia Ad- hoc Network based on IEEE 802.11g 1) Introduction 2) Related work 3) Experiments 3-1) Indoor without obstructions 3-2) Outdoor without obstructions 3-3) Penetrating wall 4) Results and Analysis 4-1) Indoor without obstructions 4-2) Outdoor without obstructions 4-3) Penetrating wall 5) Proposed Schemes and Protocols 6) Large scale simulations 7) Conclusions 40

41. Conclusion Distinct performance differences between indoor/outdoor environment and penetrating walls Improved end-to-end bandwidth significantly Carefully choose node-to-node routing distances Still in process To optimize the performance improvement – placement flexibility Challenge: Support concurrent connections simultaneously Achieving global optimization (Bandwidth, Fairness and QoS) 41

42. Observations Outdoor experiments – conducted when there are less vehicles and neglected many environmental obstacles 42

43. Questions??? 43