Asynchronous Media Streaming Over Wireless Broadcast Channels

IEEE Network, 2006

We discuss wireless broadcasting of multimedia streams within a framework which allows asynchronous media access. Receivers subscribe at any time to the ongoing broadcast session, but are still able to display the media stream from the beginning. A fully scalable broadcasting scheme is presented where the media stream is appropriately segmented and segments are protected by fountain codes. Erasure based decoding as well as soft-decoding is discussed. Asynchronous data reception and full reliability are achieved at the same time. Depending on its receiving conditions the receiver adapts its initial playout delay to guarantee high reliability of successful playout.

inf.uni-konstanz.de

2007 IEEE International Symposium on Circuits and Systems, 2007

Digital fountain codes are becoming increasingly important for multimedia communications over networks subject to packet erasures. These codes have significantly lower complexity than Reed-Solomon ones, exhibit high erasure correction performance, and are very well suited to generating multiple equally important descriptions of a source. In this paper we propose an innovative scheme for streaming multimedia contents by using digital fountain codes applied over sliding windows, along with a suitably modified belief-propagation decoder. The use of overlapped windows allows one to have a virtually extended block, which yields superior performance in terms of packet recovery. Simulation results using LT codes show that the proposed algorithm has better performance in terms of efficiency, reliability and memory with respect to fixed-window encoding.

Wireless Communications and Mobile Computing, 2012

This paper addresses the problem of streaming packetized media data in a combined wireline/802.11 network. Since the wireless channel is normally the bottleneck for media streaming in such a network, we propose that wireless fountain coding (WFC) be used over the wireless downlink in order to efficiently utilize the wireless bandwidth and exploit the broadcast nature of the channel. Forward error correction (FEC) is also used to combat errors at the application-layer. We analytically obtain the moment generating function (MGF) for the wireless link-layer delay incurred by WFC. With the MGF, the expected value of this wireless link-layer delay is found and used by the access point (AP), who has no knowledge of the buffer contents of wireless receivers, to make a coding-based decision. We then derive the end-to-end packet loss/late probability based on the MGF. We develop an integrated ns-3/EvalVid simulator to evaluate our proposed system and compare it with the traditional 802.11e scheme which is without WFC capability but equipped with application-and linklayer retransmission mechanisms. Through extensive simulations of video streaming, we show that streaming with WFC is able to support more concurrent video flows compared to the traditional scheme. When the deadlines imposed on video packets are relatively stringent, streaming with WFC also shows superior performance in terms of packet loss/late probability, video distortion, and video frame delay, over the traditional scheme.

2008 Third International Conference on Pervasive Computing and Applications, 2008

Video streaming is sensitive to packet loss, which can severely damage the quality of the received video. Video communication systems that rely on application-layer forward error correction (FEC) to combat packet loss are particularly suitable for pervasive computing because they can be used on top of any existing network architecture. However, since in heterogeneous environments network conditions are unpredictable, determining the right amount of redundancy introduced by the channel encoder is not obvious. This paper presents a practical implementation of a unicast video streaming system that solves this problem by using a rateless code and receiver feedback. In real simulations over the Internet our solution outperformed a standard approach based on fixed-rate forward error correction. For an Internet connection Konstanz-Beijing-Konstanz and the standard Foreman sequence compressed with the H.264 video coder, the gain in average peak signal to noise ratio exceeded 3.5 decibels at 90 kilobits per second.

The proliferation of applications that must reliably distribute large, rich content to a vast number of autonomous receivers motivates the design of new multicast and broadcast protocols. We describe an ideal, fully scalable protocol for these applications that we call a digital fountain. A digital fountain allows any number of heterogeneous receivers to acquire content with optimal efficiency at times of their choosing. Moreover, no feedback channels are needed to ensure reliable delivery, even in the face of high loss rates.

2006

In this work we address reliable file delivery over mobile broadcast networks, concentrating on the Raptor codes as specified for Multimedia Broadcast/Multicast Services (MBMS) within 3GPP. We start by describing Luby-Transform (LT) codes, which are the first practical fountain codes. Then, using a natural and easy to understand linear algebra notation, we describe Raptor codes as a powerful extension of LT codes. We provide some insight into the Raptor code structure and some guidelines for implementation of encoders and decoders. Finally, some selected simulations verify the good performance of file distribution with Raptor codes as specified in 3GPP. References to a complete set of simulation results are also provided.

IEEE Journal on Selected Areas in Communications, 2002

The proliferation of applications that must reliably distribute large, rich content to a vast number of autonomous receivers motivates the design of new multicast and broadcast protocols. We describe an ideal, fully scalable protocol for these applications that we call a digital fountain. A digital fountain allows any number of heterogeneous receivers to acquire content with optimal efficiency at times of their choosing. Moreover, no feedback channels are needed to ensure reliable delivery, even in the face of high loss rates.

2016

— Video streaming over the Internet and packet-based wireless networks is sensitive to packet loss, which can severely damage the quality of the received video. To protect the transmitted video data against packet loss, application-layer forward error correction (FEC) is commonly used. Typically, for a given source block, the channel code rate is fixed in advance according to an estimation of the packet loss rate. However, since network conditions are difficult to predict, determining the right amount of redundancy introduced by the channel encoder is not obvious. To address this problem, we consider a general framework where the sender applies rateless erasure coding to every source block and keeps on transmitting the encoded symbols until it receives an acknowledgment from the receiver indicating that the block was decoded successfully. Within this framework, we design transmission strategies that aim at minimizing the expected bandwidth usage while ensuring successful decoding su...

2014 IEEE Symposium on Computers and Communications (ISCC), 2014

The diffusion of mobile devices, that are capable to play videos, opened new challenges for video streaming applications. Since wireless communications are prone to erasures, an important goal is to research possible ways to reliably provide video content. Fountain codes are an efficient way to protect video streaming against erasures: in particular, burst erasures are the ones that can significantly reduce the quality of the transmitted video. In this work, Luby codes for burst erasure channels are investigated. Our main focus is on the design of Luby codes to make the receiver able to recover all the lost information without any retransmission. Furthermore, we analytically demonstrate that lower energy consumption is achievable by using LT codes instead of a general retransmission scheme.