A Digital Fountain Approach to Asynchronous

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.

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.

ACM SIGCOMM Computer Communication Review, 1998

The proliferation of applications that must reliably distribute bulk data to a large number of autonomous clients 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 clients to acquire bulk data 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.

2005 IEEE International Conference on Multimedia and Expo, 2005

We consider wireless broadcasting of multimedia content to allow 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. The decoding behavior of rateless codes on wireless as well as on erasure channels is considered within the framework of information collection. Asynchronous data access and full reliability at the same time are achieved. Depending on its receiving conditions the receiver adapts its initial playout delay for high probability of successful playout. Analytical expressions for the failure probability of successful media playout are derived depending on the initial delay and the channel conditions at the receiver.

the spectral efficiency. The OFDM system is implemented in practice using the discrete fourier transform (DFT). Recall from signals and systems theory that the sinusoids of the DFT forms an orthogonal basis set and a signal in the vector space of the

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.

Anais de XXIX Simpósio Brasileiro de Telecomunicações, 2011

The real-time transport of multi-media over IP faces issues, such as packet drops and jitter, that might generate severe impairments in the content being decoded at the reception. Channel coding is the most effective measure for overcoming these issues, since the latency imposed by retransmission protocols is not desirable. There are channel coding schemes specified in recommendations and standards, widely adopted by equipment vendors today. Among these, Fountain Codes present attractive characteristics for such applications. This article proposes an unequal protection scheme for Transport Streams over RTP/UDP/IP employing Fountain codes and presents comparative results of simulations performed with these and other channel coding schemes commonly adopted today.

IEEE Transactions on Information Theory, 2016

We study a content delivery problem in a K-user erasure broadcast channel such that a content providing server wishes to deliver requested files to users, each equipped with a cache of a finite memory. Assuming that the transmitter has state feedback and user caches can be filled during off-peak hours reliably by the decentralized content placement, we characterize the achievable rate region as a function of the memory sizes and the erasure probabilities. The proposed delivery scheme, based on the broadcasting scheme by Wang and Gatzianas et al., exploits the receiver side information established during the placement phase. Our results can be extended to centralized content placement as well as multi-antenna broadcast channels with state feedback.

inf.uni-konstanz.de

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.