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40
Improving qos in high-speed mobility using bandwidth maps
- IEEE Transactions on Mobile Computing
, 2011
"... Abstract—It is widely evidenced that location has a significant influence on the actual bandwidth that can be expected from Wireless Wide Area Networks (WWANs), e.g., 3G. Because a fast-moving vehicle continuously changes its location, vehicular mobile computing is confronted with the possibility of ..."
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Abstract—It is widely evidenced that location has a significant influence on the actual bandwidth that can be expected from Wireless Wide Area Networks (WWANs), e.g., 3G. Because a fast-moving vehicle continuously changes its location, vehicular mobile computing is confronted with the possibility of significant variations in available network bandwidth. While it is difficult for providers to eliminate bandwidth disparity over a large service area, it may be possible to map network bandwidth to the road network through repeated measurements. In this paper, we report results of an extensive measurement campaign to demonstrate the viability of such bandwidth maps. We show how bandwidth maps can be interfaced with adaptive multimedia servers and the emerging vehicular communication systems that use on-board mobile routers to deliver Internet services to the passengers. Using simulation experiments driven by our measurement data, we quantify the improvement in Quality of Service (QoS) that can be achieved by taking advantage of the geographical knowledge of bandwidth provided by the bandwidth maps. We find that our approach reduces the frequency of disruptions in perceived QoS for both audio and video applications in high-speed vehicular mobility by several orders of magnitude. Index Terms—Location-dependent and sensitive, mobile computing, mobile environments, mobile communication systems. Ç 1
A Distortion-minimizing Rate Controller for Wireless Multimedia Sensor Networks
- Computer Communications (Elsevier
, 2010
"... Abstract—The availability of inexpensive CMOS cameras and microphones that can ubiquitously capture multimedia content from the environment is fostering the development of Wireless Multimedia Sensor Networks (WMSNs), i.e., distributed systems of wirelessly networked devices that can retrieve video a ..."
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Abstract—The availability of inexpensive CMOS cameras and microphones that can ubiquitously capture multimedia content from the environment is fostering the development of Wireless Multimedia Sensor Networks (WMSNs), i.e., distributed systems of wirelessly networked devices that can retrieve video and audio streams, still images, and scalar sensor data. WMSNs require the sensor network paradigm to be re-thought in view of the need for mechanisms to deliver multimedia content with a pre-defined level of quality of service (QoS). A new rate control scheme for WMSNs is introduced in this paper with a two-fold objective: i) maximize the video quality of each individual video stream; ii) maintain fairness in video quality between different video streams. The rate control scheme is based on both analytical and empirical models and consists of a new cross-layer control algorithm that jointly regulates the end-to-end data rate, the video quality, and the strength of the channel coding at the physical layer. The end-to-end data rate is regulated to avoid congestion while maintaining fairness in the domain of video quality rather than data rate. Once the endto-end data rate has been determined, the sender adjusts the video encoder rate and the channel encoder rate based on the overall rate and the current channel quality, with the objective of minimizing the distortion of the received video. Simulations show that the proposed algorithm considerably improves the received video quality without sacrificing fairness. I.
Empirical evaluation of HTTP adaptive streaming under vehicular mobility
- In Proc. of the International Conference on Networking - Volume Part I (IFIP NETWORKING
, 2011
"... Abstract. Adaptive streaming is a promising technique for delivering a high-quality video streaming experience. In this technique, the streaming bit-rate is constantly adjusted in accordance to the variations in the un-derlying network bandwidth conditions. A popular instantiation of this approach i ..."
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Abstract. Adaptive streaming is a promising technique for delivering a high-quality video streaming experience. In this technique, the streaming bit-rate is constantly adjusted in accordance to the variations in the un-derlying network bandwidth conditions. A popular instantiation of this approach is to extend traditional HTTP-based streaming. While several such implementations are widely available, it is unclear how they perform under a typical high-speed vehicular environment, wherein the wireless bandwidth varies significantly and rapidly. In this paper, we seek to pro-vide some insights on this issue through empirical experiments driven by real-world wireless bandwidth traces collected from moving vehicles. Our results suggest that, with appropriate parameter configurations, HTTP adaptive streaming is an effective solution for delivering a high-quality smooth streaming experience even under high-speed vehicular mobility.
G.-M.; “Performance Evaluation of Multimedia Content Distribution Over Multi-Homed Wireless Networks
- IEEE Transactions on Broadcasting Issue
, 2011
"... Abstract—The growing availability of IP based heterogeneous wireless access technologies coupled with the increasing capabil-ities of mobile devices is creating opportunities for multimedia dis-tribution. Through its multi-homing feature, the ability to sup-port multiple network connections in a sin ..."
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Cited by 7 (3 self)
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Abstract—The growing availability of IP based heterogeneous wireless access technologies coupled with the increasing capabil-ities of mobile devices is creating opportunities for multimedia dis-tribution. Through its multi-homing feature, the ability to sup-port multiple network connections in a single end to end associ-ation, the transport layer Stream Control Transmission Protocol (SCTP) can enable seamless and transparent communication ses-sions over multiple heterogeneous networks. This paper analyzes the performance of multimedia distribution when making use of two multi-homing SCTP-based approaches: Single Path Transfer and Concurrent Multi-path Transfer, in which a single or all paths within an association are used simultaneously for data transmis-sion. In this investigation various retransmission policies and dif-ferent parameter sets are used in turn and recommendations are made for achieving best results during video delivery. In order to perform this study a novel realistic evaluation tool-set was pro-posed and is described, which can simulate video delivery over SCTP. Our simulation results and analysis show how to optimize the transmission of multimedia content over SCTP associations in both single and multipath scenarios. Index Terms—Concurrent multi-path transfer, multi-homing, multimedia distribution, SCTP, single path transfer. I.
Quality Improvement of Mobile Video Using Geointelligent Rate Adaptation
- In Proc. of IEEE WCNC
, 2010
"... Abstract—Adaptive video is a popular technique to continu-ously deliver a video stream to a user in the best quality possible when the underlying network bandwidth cannot be guaranteed. As such, quality of adaptive video depends critically on the agility of the rate adaptation algorithms in tracking ..."
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Abstract—Adaptive video is a popular technique to continu-ously deliver a video stream to a user in the best quality possible when the underlying network bandwidth cannot be guaranteed. As such, quality of adaptive video depends critically on the agility of the rate adaptation algorithms in tracking the varying bandwidth. In this paper, we investigate the performance of a popular rate adaptation algorithm, namely, TCP-friendly rate control (TFRC), in vehicular environments. Our results show that TFRC cannot cope well with the pattern of bandwidth changes faced by a user travelling in a fast moving vehicle, resulting in poor viewing experience. Motivated by the observation that bandwidth changes in vehicular environment is significantly influenced by the rapid change of user’s geographic location, we propose Geo-TFRC, which empowers TFRC with a novel street-level bandwidth map that holds summary of past band-width observations for each segment of the street. We conduct simulation experiments which are driven by the real High-Speed Downlink Packet Access (HSDPA) bandwidth traces collected from a vehicle traveling along a route in Sydney. Our results reveal that Geo-TFRC can track the bandwidth changes much more effectively, which in turn improves the quality of the mobile video. We find our proactive approach can significantly reduce the time that a user suffers from pixelated viewing experience by up to five folds as compared to TFRC. I.
PSNR Evaluation of Media Traffic over TFRC
"... Abstract—Due to the remarkable increase in media traffic over the existing best-effort IP Internet, the Internet congestion state is expected to worsen. TCP-friendly rate control protocol TFRC is one of the most promising congestion control techniques developed so far. Those techniques have been tho ..."
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Abstract—Due to the remarkable increase in media traffic over the existing best-effort IP Internet, the Internet congestion state is expected to worsen. TCP-friendly rate control protocol TFRC is one of the most promising congestion control techniques developed so far. Those techniques have been thoroughly tested in terms of being TCP-friendly and fair. Yet, their impact on the visual quality of the media traffic traversing Internet is still questionable. This paper investigates, in a simulated environment, the effect of incorporating TFRC on the peak signal-to-noise ratio PSNR of the transmitted video over Internet. A number of arbitrary raw videos are encoded, converted into trace files via a known tool-set, and then pushed into a simulated network environment to run over TFRC protocol with coexisting TCP flows. This scenario was run for a variety of videos having different content types, frame lengths, and motion complexity scale. The output video files of the simulations are then examined in terms of PSNR. TFRC was shown to produce visually meaningful and acceptable output video files. Some variations in the PSNR values were recorded among the simulated videos. TFRC performance on slow motion videos was slightly better than on medium-motion that was better than that on high-motion videos.
Performance Evaluation of Distributing Real-time Video over Concurrent Multipath
"... (CMT) and CMT with a Potentially-Failed destination state (CMT-PF) uses the transport layer multi-homing protocol Stream Control Transmission Protocol (SCTP) to increase application throughput by distributing transmitted data across multiple end-to-end paths. This paper investigates and evaluates th ..."
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(CMT) and CMT with a Potentially-Failed destination state (CMT-PF) uses the transport layer multi-homing protocol Stream Control Transmission Protocol (SCTP) to increase application throughput by distributing transmitted data across multiple end-to-end paths. This paper investigates and evaluates the performance of CMT with Partial Reliability (CMT-PR) and CMT-PF with Partial Reliability (CMT-PF-PR), novel extensions of SCTP for real-time video distribution. The Evalvid-CMT platform was implemented in the University of Delaware’s SCTP/CMT ns-2 module to perform emulation experiments in order to compare CMT and CMT-PR, CMT-PF and CMT-PF-PR, respectively. The results presented in the paper show how the CMT-PR and CMT-PF-PR outperform CMT and CMT-PF respectively. Consequently the former are suggested as strategies for real-time video concurrent multipath transmissions.
A Cross-layer Design for Video Transmission with TFRC in MANETs
"... Mobile Ad hoc NETworks (MANETs) are becoming more essential to wireless communications due to growing popularity of mobile devices. However, MANETs do not seem to effectively support multimedia applications and especially video transmission. In this work, we propose a cross-layer design that aims to ..."
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Mobile Ad hoc NETworks (MANETs) are becoming more essential to wireless communications due to growing popularity of mobile devices. However, MANETs do not seem to effectively support multimedia applications and especially video transmission. In this work, we propose a cross-layer design that aims to improve the performance of video transmission using TCP Friendly Rate Control (TFRC). Our design provides priority to video packets and exploits information from the MAC layer in order to improve TFRC’s performance. The proposed cross-layer mechanism utilizes Signal to Noise Ratio (SNR) measurements along the routing path, in order to make the route reconstruction procedure more efficient. Simulation results show that both the use of traffic categorization and the SNR utilization lead to important improvements of video transmission over the mobile Ad hoc network. More specifically, simulations indicate increased average Peak Signal to Noise Ratio (PSNR) for the received video, increased throughput and packet delivery ration, as well as reduced average end-to-end delay. 1
Simulcast Transmission for Video Applications: Performance Evaluation with an Integrated Simulation Environment
"... Abstract — This paper presents the performance evaluation of a multi-rate multicast protocol named Adaptive Smooth Simulcast Protocol (ASSP) for simulcast video transmission. ASSP implements a single rate TCP-friendly protocol as the underlying congestion control mechanism for each simulcast stream. ..."
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Abstract — This paper presents the performance evaluation of a multi-rate multicast protocol named Adaptive Smooth Simulcast Protocol (ASSP) for simulcast video transmission. ASSP implements a single rate TCP-friendly protocol as the underlying congestion control mechanism for each simulcast stream. ASSP is built on top of the RTP/RTCP protocol and exploits the RTCP sender and receiver reports for the dissemination of feedback information. The key attributes of ASSP are: a) TCP-friendly behavior, b) adaptive per-stream transmission rates, c) adaptive scalability to large sets of receivers and finally d) smooth transmission rates that are suitable for multimedia applications. We evaluate the performance of ASSP under an integrated simulation environment, which extends ns-2 and Evalvid-RA into the multicast domain with the use of RTP/RTCP protocols. Simulations conducted under this environment combine the measurements of network metrics along with objective evaluation criteria on the perceived video quality by the end user. Keywords-component; Multicast; congestion control; multimedia transmission; ns2; simulation
