Multi-user video streaming using unequal error protection network coding in wireless networks

In this paper, we investigate a multi-user video streaming system applying unequal error protection (UEP) network coding (NC) for simultaneous real-time exchange of scalable video streams among multiple users. We focus on a simple wireless scenario where users exchange encoded data packets over a common central network node (e.g., a base station or an access point) that aims to capture the fundamental system behaviour. Our goal is to present analytical tools that provide both the decoding probability analysis and the expected delay guarantees for different importance layers of scalable video streams. Using the proposed tools, we offer a simple framework for design and analysis of UEP NC based multi-user video streaming systems and provide examples of system design for video conferencing scenario in broadband wireless cellular networks

Проблемы передачи потокового видео по симплексному каналу сети с потерями данных

Разработана классификация основных проблем и задач, связанных с потерей части информации при передаче потокового видео по симплексному каналу связи, а также направлений в области их решения. Показано, что метод прямого исправления ошибок (ПИО) является наиболее общим подходом защиты от ошибок в рамках рассматриваемой задачи. Проанализированы работы в данной области и показана необходимость разработки нового метода применения ПИО, не привязанного к способу кодирования видеоизображения, с переменно-дискретным коэффициентом избыточности, обладающего низкой сложностью вычислений и обеспечивающего работу в режиме реального времени на современных компьютерах.Розроблено класифікацію основних проблем і задач, пов’язаних з утратою частини інформації при передачі потокового відео симплексним каналом зв’язку, а також напрямків в області їхнього рішення. Показано, що метод прямого виправлення помилок (ПВП) є найбільш загальним підходом захисту від помилок у рамках розглянутого завдання. Проаналізовано роботи в даній області та показано необхідність розробки нового методу застосування ПВП, що не прив’язаний до способу кодування відеозображення, зі змінно-дискретним коефіцієнтом надлишковості, що має низьку складність обчислень і забезпечує передачу даних у режимі реального часу на сучасних комп’ютерах.Classification of problems and tasks related to loss of a part of data in case of video streaming transmission over simplex channel and directions in domain of their solving are developed. It is shown that forward error correction (FEC) is the most general approach to error protection within the scope of the given task. A number of works in the given field are analyzed and necessity of new FEC method development is shown. The method should be independent of video coding scheme, with varying redundancy ratio for each data element and a speed of calculations sufficient for using in real time on modern computers

Multiple Description Video Coding Using Joint Frame Duplication/Interpolation

Multiple description coding (MDC) is a promising alternative to combatting information loss without any retransmission. In this paper, an effective MD video codec is designed based on temporal pre- and post-processing of video sequences without modifying the actual coding process itself, which makes it compatible with the current standard source or channel codec. For ease of post-processing, motion-compensated interpolation (MCI) based on piecewise uniform motion assumption is adopted to estimate the lost frame in side decoding. Accordingly, to match the post-processing, in the pre-processing joint frame duplication/interpolation is first applied to the original video data before performing odd/even frame splitting, which attempts to make the motion variety in the generated descriptions piecewise uniformly thus achieving better side reconstructed quality based on MCI. The experimental results exhibit better performance of the proposed scheme than some other tested schemes, in both the on-off channel environment and packet loss network

Multicarrier CDMA: A very promissing multiple access scheme for future wideband wireless networks

International audienceIn this paper, multicarrier techniques are studied in the context of the future wideband wireless networks. After a brief presentation of the third generation mobile networks, MC-CDMA systems are considered for the downlink of the future high rate cellular networks. The performance of different mono-user and multi-user detection techniques are compared with the help of Monte Carlo simulations over a frequency selective Rayleigh channel. Thus, the efficiency of MC-CDMA as a very promising multiple access and robust modulation scheme is successfully demonstrated for the downlink of the future wideband mobile networks. Finally, the first results concerning the performance of Multicarrier CDMA technique combined with space-time block coding in order to build a Multiple Input Multiple Output/MC-CDMA system are presented over a Rayleigh channel

Robust live unicast video streaming with rateless codes

"This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.""©2007 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE."We consider live unicast video streaming over a packet erasure channel. To protect the transmitted data, previous solutions use forward error correction (FEC), where the channel code rate is fixed in advance according to an estimation of the packet loss rate. However, these solutions are inefficient under dynamic and unpredictable channel conditions because of the mismatch between the estimated packet loss rate and the actual one.We introduce a new approach based on rateless codes and receiver feedback. For every source block, the sender 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 provide an efficient algorithm to minimize bandwidth usage while ensuring successful decoding subject to an upper bound on the packet loss rate. Experimental results showed that compared to traditional fixed-rate FEC, our scheme provides significant bandwidth savings for the same playback qualityThis work was supported by the DFG Research Training Group GK-1042