Multiple Description Video Multicast in Wireless Ad Hoc Networks

1. Multiple Description Video Multicast in Wireless Ad Hoc Networks Shiwen Mao,Xiaolin Cheng ,Y. Thomas Hou,Hanif D. Sherali Presenter: Monika Srivastava (CSUID 2438527) Computer & Information Science Dept.

2. Multiple Description Video Multicastin Wireless Ad Hoc Networks • Multiple Descriptions: Multiple Equally important streams of video • Multicast : Sending video streams to more than one receiver • Wireless Ad Hoc Networks : set of hosts over a wireless channel Objective: To optimize the application layer performance metric, that is, Video Distortion Technique: • One Sender, Multiple Receivers • One Video Session, Multiple Descriptions • One Description, Multiple Layers • Multicast Trees One Tree  One Video Description

3. Base Layer Receivers Desc1 Desc 2 Enhancement Layer Description 1 MulticastTrees Sender Description 2

4. Multiple Description Video Multicastin Wireless Ad Hoc Networks Effectively Deals with • Link Failure • Diverse Bandwidth of Receivers Problem: How to find multiple trees such that the overall video quality is optimized? Solution: Application Centric , Cross Layer Approach Input: A wireless Ad Hoc Network, A sender, Multicast session with M receivers Output: a pair of multicast trees

5. Multiple Description Video Multicastin Wireless Ad Hoc Networks Genetic Algorithm Based Solution Procedure • Initial Population • Genetic Operation 1.Fitness : inverse of distortion 2.Selection : potential individuals 3.Crossover 4.Mutation • Output : optimum solution, with higher generations Individual with Highest Fitness is taken as solution

6. Multiple Description Video Multicastin Wireless Ad Hoc Networks • Performance Evaluation Network Centric Algorithms • Bounded Shortest Multicast Algortihm (BSMA) One tree with optimal loss One tree with largest bandwidth • Independent Tree Ad Hoc Multicast Routing(ITAMAR) Trees for use Trees for backup

7. Multiple Description Video Multicastin Wireless Ad Hoc Networks • Performance Comparison Source node s, receivers r Link failure probability [0,1] Available link bandwidth [100kbps,800kbps] Average Distortion was calculated Participants: BSMA,ITAMAR and GA

8. Multiple Description Video Multicastin Wireless Ad Hoc Networks Result: And the winner is … Genetic Algorithm based Approach (lowest distortion) Reasons for better performance of GA • BSMA and ITAMAR only optimize the network layer performance metrics whereas GA uses an application layer centric approach • GA optimizes video distortion

9. Multiple Description Video Multicastin Wireless Ad Hoc Networks Applications: Used In networks to prevent webservers from being overwhelmed by a large flash crowd Can be used in cases where video transmission is required and receivers have diverse bandwidths

10. Conclusion Algortihms for Multiple Description Video Multicast routing problem BSMA and ITAMAR Algorithm Strong Point: Lower Computational complexity Weak Point : Video distortion is high Genetic Algorithm Approach: • Well suited for parallel computation • Set of “good trees” in very small delay • Though somewhat complex but worth using

11. Thank You !