Jianwei Huang

Zhu Li

Qian Zhang

Collaboration and Optimization for Multimedia Communications

We present a stream tapping protocol that involves clients in the video distribution process.  As in conventional stream tapping, our protocol allows new clients to tap the most recent broadcast of the video they are watching. While conventional stream tapping required the server to send to these clients the part of the video they missed, our protocol delegates this task to the clients that are already watching the video, thus greatly reducing the workload of the server.  Unlike previous solutions involving clients in the video distribution process, our protocol works with clients that can only upload video data at a fraction of the video consumption rate and includes a mechanism to control its network bandwidth consumption.

Santosh Kulkarni

Jehan-Fran&#xE7;ois P&#xE2;ris

Purvi Shah

A Stream Tapping Protocol Involving Clients in the Distribution of Videos on Demand

Although cross-layer has been thought as one of the most effective and efficient ways for multimedia communications over wireless networks and a plethora of research has been done in this area, there is still lacking of a rigorous mathematical model to gain in-depth understanding of cross-layer design tradeoffs, spanning from application layer to physical layer. As a result, many existing cross-layer designs enhance the performance of certain layers at the price of either introducing side effects to the overall system performance or violating the syntax and semantics of the layered network architecture. Therefore, lacking of a rigorous theoretical study makes existing cross-layer designs rely on heuristic approaches which are unable to guarantee sound results efficiently and consistently. In this paper, we attempt to fill this gap and develop a new methodological foundation for cross-layer design in wireless multimedia communications. We first introduce a delay-distortion-driven cross-layer optimization framework which can be solved as a large-scale dynamic programming problem. Then, we present new approximate dynamic programming based on significance measure and sensitivity analysis for high-dimensional nonlinear cross-layer optimization in support of real-time multimedia applications. The major contribution of this paper is to present the first rigorous theoretical modeling for integrated cross-layer control and optimization in wireless multimedia communications, providing design insights into multimedia communications over current wireless networks and throwing light on design optimization of the next-generation wireless multimedia systems and networks.

Song Ci

Haohong Wang

Dalei Wu

A Theoretical Framework for Quality-Aware Cross-Layer Optimized Wireless Multimedia Communications

Aggregates of real-time traffic may experience changes in their statistical characteristics often manifesting non stationary behavior. In multi protocol label switching (MPLS) networks this type of the traffic is assigned constant amount of resources. This may result in ineffective usage of resources when the load is below than expected or inappropriate performance when the load is higher. In this paper we propose new algorithm for dynamic resource adaptation to temporarily changing traffic conditions. Assuming that network nodes may reallocate resources on-demand using automatic bandwidth adjustment capability of MPLS framework, the proposed algorithm, implemented at ingress MPLS nodes, dynamically decides which amount of resources is currently sufficient to handle arriving traffic with given performance metrics. This decision is then communicated to interior MPLS nodes along the label switched path. As a basic tool of the algorithm we use change-point statistical test that signals time instants at which statistical characteristics of traffic aggregates change. The major advantage of the proposed approach is that it is fully autonomous, that is, network nodes do not need any support from hosts in terms of resource reservation requests. The proposed algorithm is well suited for traffic patterns experiencing high variability, especially, 
for non stationary type of the traffic.

D. Moltchanov

Automatic Bandwidth Adjustment for Content Distribution in MPLS Networks

A collaborative access scheme that exploits the broadcast
nature of the wireless communication in order to achieve multicast
content delivery is presented in this paper. The key idea is that individual
clients requesting for the same content can collaborate and share the same
data channel. As opposed to broadcasting, this method enables the clients
to determine online the delivered content, and thus supports on-demand
services. On the other hand, a multicast content delivery is much more
efficient than a unicast content distribution, which must use a dedicated
data channel per each and every client. This method is particularly
suitable for sessions having a long-time duration, for applications in which
clients can subscribe to ahead of time, and for applications in which the
clients receive the same information simultaneously. A multicast content
distribution increases the network service throughput in terms of the
expected number of clients served simultaneously, and therefore it offers
a reduced waiting time for content delivery at highly loaded time periods.
It is shown that the problem of maximizing the efficiency of distributing
a content in a wireless network is NP-hard. An approximation algorithm
is therefore used, that for any <svg style="vertical-align:-0.30096pt;width:62.099998px;" id="M1" height="11.0625" version="1.1" viewBox="0 0 62.099998 11.0625" width="62.099998"  xmlns="http://www.w3.org/2000/svg">
	<g transform="matrix(1.25,0,0,-1.25,0,11.0625)">
		<g transform="translate(72,-63.15)">
			<text transform="matrix(1,0,0,-1,-71.95,63.5)">
				<tspan style="font-size: 12.50px; " x="0" y="0">0</tspan>
				<tspan style="font-size: 12.50px; " x="9.7148314" y="0">&lt;</tspan>
				<tspan style="font-size: 12.50px; " x="21.75522" y="0">𝜀</tspan>
				<tspan style="font-size: 12.50px; " x="31.282507" y="0">&lt;</tspan>
				<tspan style="font-size: 12.50px; " x="43.322895" y="0">1</tspan>
			</text>

		</g>
	</g>
</svg>  finds an approximation solution
with a relative accuracy <svg style="vertical-align:-0.13794pt;width:7.6875px;" id="M2" height="7.1875" version="1.1" viewBox="0 0 7.6875 7.1875" width="7.6875"  xmlns="http://www.w3.org/2000/svg">
	<g transform="matrix(1.25,0,0,-1.25,0,7.1875)">
		<g transform="translate(72,-66.25)">
			<text transform="matrix(1,0,0,-1,-71.95,66.44)">
				<tspan style="font-size: 12.50px; " x="0" y="0">𝜀</tspan>
			</text>

		</g>
	</g>
</svg>. The proposed method does not require any hardware modification on the network equipment. Thus, it can be easily
implemented.

Zohar Naor

A Collaborative Wireless Access to On-Demand Services

We consider rate-distortion optimized strategies for dropping frames from multiple conversational and streaming videos sharing limited network node resources. The dropping strategies are based on side information that is extracted during encoding and is sent along the regular bitstream. The additional transmission overhead and the computational complexity of the proposed frame dropping schemes are analyzed. Our experimental results show that a significant improvement in end-to-end performance is achieved compared to priority-based random early dropping.

Wei Tu

Jacob Chakareski

Eckehard Steinbach

Rate-Distortion Optimized Frame Dropping for Multiuser Streaming and Conversational Videos

Scalable video coding (SVC) is a new video coding format which provides scalability in three-dimensional (spatio-temporal-SNR) space. In this paper, we focus on the adaptation in SNR dimension. Usually, an SVC bitstream may contain multiple spatial layers, and each spatial layer may be enhanced by several FGS layers. To meet a bitrate constraint, the fine-grained scalability (FGS) data of different spatial layers can be truncated in various manners. However, the contributions of FGS layers to the overall/collective video quality are different. In this work, we propose an optimized framework to control the SNR scalability across multiple spatial layers. Our proposed framework has the flexibility in allocating the resource (i.e., bitrate) among spatial layers, where the overall quality is defined as a function of all spatial layers' qualities and can be modified on the fly.

Truong Cong Thang

Jung Won Kang

Jeong-Ju Yoo

Yong Man Ro

Optimal Multilayer Adaptation of SVC Video over Heterogeneous Environments

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<p><em>Advances in Multimedia</em> publishes research on the technologies associated with multimedia systems, including computer-media integration for digital information processing, storage, transmission, and representation.</p>


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Advances in Multimedia

Collaboration and Optimization for Multimedia Communications

Collaboration and Optimization for Multimedia Communications

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