Joint routing and rate allocation for multiple video streams

Abstract: The support for multiple video streams in an ad hoc wireless network requires appropriate routing and rate allocation measures, which ascertain the set of links for transmitting each stream and the encoding rate of the video to be delivered over

Zhu et al. / J Zhejiang Univ SCIENCE B 2006 7():

Journal of Zhejiang University SCIENCE B

ISSN 1673-1581

http://doc.guandang.net/jzus E-mail: jzus@http://doc.guandang.net

1

Joint Routing and Rate Allocation for Multiple Video Streams

in Ad-hoc Wireless Networks

Xiaoqing Zhu , Jatinder Pal Singh*, and Bernd Girod

(Information System Laboratory, Stanford University, California, USA)

E-mail: {zhuxq, girod}@stanford.edu

*(Deutsche Telekom Laboratories, Ernst-Reuter-Platz 7, 10587 Berlin, Germany)

E-mail: jatinder.singh@telekom.de

Received Dec. 19, 2006; revision accepted Feb. 19, 2006

Abstract: The support for multiple video streams in an ad hoc wireless network requires appropriate routing and rate allocation measures, which ascertain the set of links for transmitting each stream and the encoding rate of the video to be delivered over the chosen links. The routing and rate allocation procedures impact the sustained quality of each video stream measured as the mean squared error (MSE) distortion at the receiver, and the overall network congestion in terms of queuing delay per link. We study the trade-off between these two competing objectives in a convex optimization formulation, and discuss both centralized and dis-tributed solutions for joint routing and rate allocation for multiple streams. For each stream, the optimal allocated rate strikes a balance between the selfish motive of minimizing video distortion and the global good of minimizing network congestions, while the routes are chosen over the least-congested links in the network. In addition to detailed analysis, network simulation results using ns-2 are presented to study the optimal choice of parameters and to confirm the effectiveness of the proposed measures.

Key words: Ad-hoc wireless networks, video streaming, rate allocation, multi-path routing

doi:10.1631/jzus.2006.B0001 Document code: A CLC number: R979.1

1. Introduction

Ad hoc networks are attractive owing to their self-organizing nature and absence of a fixed infra-structure. They are particularly suited for communi-cation in disaster-affected areas, coordinating military operations, and sensing environmental conditions. With the growing availability of supporting hardware and decreasing equipment cost, ad-hoc networking based applications are proliferating. Meshes of wire-less nodes are being deployed in cities and housing communities to support Internet access and peer-to-peer communication (Cass 2005; Bicket et al., 2005). Streaming of multimedia content over such kind of networks is compelling for many application scenarios, including vehicular platoons, community meshes, and home entertainment networks.

The nodes in an ad hoc network communicate in a peer-to-peer fashion and help in relaying data from a

source to the destination. Routing is a challenging task owing to the dynamic network topology and variations in wireless channel conditions. Over the years several distributed protocols have been pro-posed and analyzed for ad-hoc routing. Many of them employ simple metrics such as hop count or end-to-end delay while selecting a route between a given source and a destination. Routing mechanisms that make use of the existence of multiple paths be-tween a source-destination pair have also been pro-posed, and are shown to result in enhanced perform-ance over single-path routing methods (Lee and Gerla, 2000; Marina and Das, 2001).

Video streaming applications additionally impose high rate requirement and stringent latency con-straints on resource-limited ad hoc networks. It is observed that quality of the received video stream is affected not only by encoder quantization, but also by self-inflicted network congestion that lead to packet

Abstract: The support for multiple video streams in an ad hoc wireless network requires appropriate routing and rate allocation measures, which ascertain the set of links for transmitting each stream and the encoding rate of the video to be delivered over

2 Onji et al. / J Zhejiang Univ SCIENCE B 2006 7():

drops due to late arrivals (Zhu et al., 2005). An at-tempt to enhance the system performance should therefore account for both metrics in a conges-tion-distortion optimized fashion. When multiple streams are present in an ad hoc network, the chosen rate and routes for each stream would also affect the performance of others. Both rate allocation and (DSR) (Johnson and Maltz, 1996) and Ad-hoc On-demand Distance Vector (AODV) routing (Per-kins et al., 2003). The former involve the evaluation and storage of the routing tables pertaining to the topology at each node. The routing tables are peri-odically updated to counter the topological changes associated with node mobility and wireless channel routing need to be optimized for all streams in the network, preferably in a decentralized manner.

In this paper, we study a convex formulation of the joint routing and rate allocation problem for mul-tiple streams. A centralized solution based on optimal flow assignment is derived as an upper bound of performance. A distributed scheme is also proposed, where the allocated rate at each stream depends on both the distortion-rate (DR) characteristic of the video and the network congestion increment, which in turn is obtained from a distributed routing procedure (Zhu and Girod, 2005a). We show that the optimal global trade-off between total video distortion of all streams versus overall network congestion can be translated into the l …… 此处隐藏：36953字，全部文档内容请下载后查看。喜欢就下载吧 ……