Presented by:
DEEPTHI.K

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A System for Peer-to-Peer Video Streaming in Resource Constrained Mobile Environments
Introduction
 Peer-to-Peer based near-live video streaming is becoming popular with users of fixed-line broadband.
 Unavailable to mobile users because they cannot meet the bitrates requirements.
 P2P-TV system enables users in a physical proximity to retrieve video chunks in a cooperative way.
 The coordinated and efficient usage of all wireless resources available to a group of mobile hosts is the key to enable P2P-TV in mobile environments.
What is Video streaming?
 2 ways to view media on the internet Downloading and streaming.
 Downloading-
The entire file is saved on your computer which you then open and view. Disadvantage of having to wait for the whole file to download before any of it can be viewed.
 Streaming-
The end user can start watching the file almost as soon as it begins downloading. The file is sent to the user in a constant stream, and the user watches it as it arrives. It is being able to broadcast live events
Internet Protocol television (IPTV)
 Internet Protocol television (IPTV) is a system through which Internet television services are delivered using the architecture and networking methods of the Internet over a packet-switched network infrastructure.
 IPTV services may be classified into three main groups:
1. live television, with or without interactivity related to the
current TV show;
2.time-shifted programming: replays a TV show that was
broadcast hours or days ago
3.video on demand : browse a catalog of videos, not related
to TV programming.
 Mobile IPTV is a technology that enables users to transmit and receive multimedia traffic including television signal, video, audio, text and graphic services through IP-based the wired and wireless networks with support for Quality of Service, security, mobility, and interactive functions. Through Mobile IPTV, users can enjoy IPTV services anywhere and even while on the move.
Peer To Peer Vs Client-Server
 2 common types of networking Architecture's, Peer to Peer and Client-Server.
 Client-Server-
Each computer or process on the network is either a client or a server. Servers are powerful computers or processes dedicated to managing disk drives , printers , or network servers . Clients are PCs or workstations on which users run applications.
 Peer to Peer-
Each node has equivalent responsibilities. No centralized data source
Literature Survey
 1st Generation Clients-
Napster was the original P2P application. Uses the central server model .
 2nd Generation Clients-
Gnutella create a de-centralized network . By connecting users to other users directly.
 3rd Generation Clients-
Fasttrack is the most famous of this generation of networks, Kazaa, Grokster and Morpheus are the names of the different clients that connect to the Fasttrack . Users of any of those clients had access to the exact same files.
Client-Server Limitations
 Scalability is hard to achieve
 Presents a single point of failure
 Requires administration
 Unused resources at the network edge
 P2P system try to address these limitations.
-efficient use of resources.
-Scalability.
-Ease of administration
System Principles
 For mobile devices users basically have the choice between high speed and good coverage area. But they cannot have both at the same time.
 Networks usually cannot deliver bitrates suitable for video streaming to every single user.
 In our new system –
-Use several wireless Internet access links at the same time and distribute the load among them.
-They do not have to use the same technology.
- Reduces the risk of fate sharing.
-A group of users in physical proximity to jointly access a video stream, by efficiently using the Internet access resources each user contributes to the group
• Cooperative P2p Streaming
 Internet access in high-speed trains
• In short stops at train stations and while running in low speeds train passengers are able to access the Internet. But travelling with higher speeds the achievable data rates drop far below their optimum .The much slower GPRS is the only available network.
System Architecture
 every mobile device have at least two wireless interfaces
• access-link & sharing-link.
 Access-link
• -Offers access to the Internet.
• -Identify by ‘l’ .
• -no of access links is higher than the no of nodes
• -nominal bitrates ‘Bl ̕ may be lower than the video stream's
• bit rate Bv .
• -actually achievable page link bit rate changes over time.0 ≤ Bl(t)≤ Bl
 Sharing-link
• -Used to communicate with other nodes.
• -bit rate is higher than video bit rate and does not have to provide
• direct internet access.
 Instantaneous combined download capacity of the system is
• B(t)=
Coordination Of Chunk Retrieval
 Centralized Control
-there is a central controller. Its task is to collect statistics
about the achieved bit rate Bl(t)
-each peer broadcast a “hello” message on the sharing page link
which contains peer ID and claims that it is the controller. If a
peer does not receive any message for a long period then it can
assume itself as controller.
-collect buffer maps from the peers outside the group and
responsible for scheduling chunk retrival.
- aware about missing data
 Decentralized Control
Chunk Schedulers
 Theoretical Scheduler
The controller is able to look into the future and determine which links will be up or down and how long each phase will last. This knowledge allows the controller to obtain the best possible set of links to transfer all chunks with the cumulative bit rate.
 Round-Robin Scheduler
controller simply picks the next available page link that is not busy with another chunk and the page link is considered being up, for scheduling the chunk retrieval without any consideration of the past activity of the link.
 Average Scheduler
It keeps a pre page link history to obtain a achievable bit rate and uptime probability availability.
 It keeps deadline for receiving the next required chunk Ck. The time when the chunk is required to played out is tdl(k)=ChunkRate *( Ck - Cplayed) with
Ck > Cplayed.
 Ck is dropped if no links is found to transmit it.
 If the measured bitrate is larger than the required video bitrate. It uses the condition B(t) ≥ 1.2 * Bv to decide whether to start using multi-load.
PERFORMANCE EVALUATION
 Uplink part models the behavior of the upload of chunks and sending of requests from the local peer to remote peers
 The down page link part models the behavior of the local peers and is set in such a way that there are two classes of links,
(i) there are UMTS links that have a nominal page link speed of 350 Kbit/s and
(ii) there are GPRS links with a nominal page link speed of 50 Kbit/s.
 From Chunk buffer model the player obtains the available chunks and checks whether the required chunk is available on-time .
Simulation Results
 Simulator is implemented in C++.
 Bit rate Bv of 600kbits/s and chunk size of 12.5 Kbytes and total 40,000 chunks.
 If we use 8 links then maximum bitrates Bl/Bv=2.67 and if we use 24 links Bl/Bv=8.0
 In fig(a) For the presented page link set the video player was able to retrieve a required chunk from the chunk buffer at the playout time. The chunk retrieval quality P as function of the number of links for each scheduler.
CONCLUSION
• Using this approach, a group of mobile nodes, which are located in physical proximity can jointly access a live video stream, whose bitrate requirements exceeds the access bitrate each individual node is equipped with.
• An initial simulation based study demonstrates the feasibility of our approach to enable delivery of near-live TV to mobile users.
• This approach is not only applicable in mobile scenarios, but also for fixed line scenarios.