Streaming over Wireless Mesh Networks
Introduction:
Multi-hop wireless mesh networks (WMNs) are emerging as a promising technology that has applications in metro-area Internet access, public safety, and transient networks. There are two types of wireless mesh networks: client-mesh networks and Infrastructure-mesh networks (infrastructure WMNs). Client-mesh networks or ad hoc networks are formed by client devices with no infrastructure required, wherein each node plays the same role and participates in packet forwarding. In contrast, infrastructure WMNs consists of mesh access points (MAPs)/routers and client devices. The MAPs are interconnected via wireless links to form a multi-hop backhaul infrastructure. One or more MAPs connect to the wired network and are referred to as the gateways. Generally a MAP has two or more radio interfaces. One radio interface is an access interface, which is for network access of clients. A second radio interface is a relay interface, which is for routing and data forwarding. Client devices (e.g., laptops, dual-mode smart phones, personal digital assistants (PDAs) etc.) associate themselves with a nearby MAP to access the wireless mesh network. Client devices do not participate in packet relay or the routing process. A client device sends (or receives) packets to (or from) it’s associated MAP. Packet delivery in the WMN is handled by the MAP through a backhaul routing protocol. In this work, we primarily focus on the infrastructure WMNs.
In multi-hop 802.11 wireless networks, the path capacity will decrease rapidly while the hop count increases, so the traditional single server-client model is obviously not suitable for video streaming applications not only because of the single point of failure and scalability concerns, but also that the end to end bandwidth is a key factor in wireless networks. To reduce the impact of the hop count on path capacity and to balance the network capacity usage, shortening the distance from the server to receiver or enabling peers to transmit data is being considered.
Streaming over wireless mesh network is a hot research area and using P2P technology in wireless mesh network is a challenge. So far, using P2P in wireless network is mainly focused on file sharing, and video streaming is becoming more and more important. We are trying to design network architecture that can support good quality streaming with the help from peer contribution and servers. That can help to balance the load of network and enhance the scalability and reliability. Unlike the P2P application in wired network, peer selecting in WMNs should consider the routing layer information.
This work is in collaboration with and supported by Thomson Inc.
Project Summary:
The system works like a bit-torrent-like P2P system with server help. There are several mesh routers in the mesh networks. Besides participating in routing and data forwarding, the mesh router will serve as a gateway to provide a connection for the mesh clients to the Internet. The video servers in this system form a content distribution network. There is a main video server which may reside outside the mesh network, the clients in the mesh network can access the main server through the mesh routers. Other surrogate video servers will be placed in different location throughout the mesh network, and they could either be outside the mesh or within the mesh like just attached to a mesh router or being a mesh client. The video servers may be placed according to the policy that each mesh client could access at least one video server within a couple of hops. Peer selection and server selection is addressed by taking into account many factors including the routing layer information.
Papers:
1. Zhu, Yingnan; Liu, Hang; Wu, Mingquan; Li, Dekai; Mathur, Saurabh, “Implementation Experience of a Prototype for Video Streaming over Wireless Mesh Networks”, CCNC, 2007
2. Yingnan Zhu, Wenjun Zeng, Hang Liu, Yang Guo; Mathur, Saurabh, "Supporting Video Streaming Services in Infrastructure Wireless Mesh Networks: Architecture and Protocols", ICC2008 (submitted)
Last Updated :
10/31/2007 14:39:16