The Effects of Wireless Channel Errors on the Quality of Real Time Ultrasound Video Transmission

2006 ◽  
Author(s):  
Carolina Hernandez ◽  
Alvaro Alesanco ◽  
Violeta Abadia ◽  
Jose Garcia
Keyword(s):  
Real Time ◽  
Video Transmission ◽  
Wireless Channel ◽  
Channel Errors

scholarly journals Cross-Layer Framework for Multiuser Real Time H.264/AVC Video Encoding and Transmission over Block Fading MIMO Channels Using Outage Probability

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Slavche Pejoski ◽  
Venceslav Kafedziski
Keyword(s):  
Real Time ◽  
Fading Channels ◽  
Video Transmission ◽  
Single Layer ◽  
Rate Distortion ◽  
Wireless Channel ◽  
Video Encoding ◽  
Cross Layer ◽  
Mimo Channels ◽  
Channel Errors

We present a framework for cross-layer optimized real time multiuser encoding of video using a single layer H.264/AVC and transmission over MIMO wireless channels. In the proposed cross-layer adaptation, the channel of every user is characterized by the probability density function of its channel mutual information and the performance of the H.264/AVC encoder is modeled by a rate distortion model that takes into account the channel errors. These models are used during the resource allocation of the available slots in a TDMA MIMO communication system with capacity achieving channel codes. This framework allows for adaptation to the statistics of the wireless channel and to the available resources in the system and utilization of the multiuser diversity of the transmitted video sequences. We show the effectiveness of the proposed framework for video transmission over Rayleigh MIMO block fading channels, when channel distribution information is available at the transmitter.

An Improved Error Concealment Based on Redundant Motion Vector Information

2012 ◽  
Vol 532-533 ◽  
pp. 1219-1224
Author(s):  
Hong Tao Deng
Keyword(s):  
Video Transmission ◽  
Error Concealment ◽  
Video Quality ◽  
Motion Vector ◽  
Compressed Video ◽  
Vector Information ◽  
Vector Estimation ◽  
Channel Errors ◽  
Bit Stream

During video transmission over error prone network, compressed video bit-stream is sensitive to channel errors that may degrade the decoded pictures severely. In order to solve this problem, error concealment technique is a useful post-processing tool for recovering the lost information. In these methods, how to estimate the lost motion vector correctly is important for the quality of decoded picture. In order to recover the lost motion vector, an Decoder Motion Vector Estimation (DMVE) criterion was proposed and have well effect for recover the lost blocks. In this paper, we propose an improved error concealment method based on DMVE, which exploits the accurate motion vector by using redundant motion vector information. The experimental results with an H.264 codec show that our method improves both subjective and objective decoder reconstructed video quality, especially for sequences of drastic motion.

QoS Support Mechanisms in WiMAX

2010 ◽  
pp. 330-346
Author(s):  
Maode Ma ◽  
Jinchang Lu
Keyword(s):  
Real Time ◽  
Packet Scheduling ◽  
Wireless Channel ◽  
Wireless Access Networks ◽  
Broadband Wireless ◽  
Wimax Networks ◽  
Real Time Traffic ◽  
Support Mechanisms ◽  
Time Varying Channel

Quality of service (QoS) provisioning is an important issue in the deployment of broadband wireless access networks e.g. WiMAX (IEEE Std 802.16-2004, 2004) networks with real-time and non-real-time traffic integrated. To design a QoS support framework tailored for WiMAX networks is more challenge as wireless channel has unique characteristics such as time-varying channel and limited channel capacity. This chapter presents various QoS support mechanisms in WiMAX networks. Existing proposals with the state-of-the-art technology have been classified into three main categories: QoS support architecture, bandwidth management mechanism, and packet scheduling schemes. Representative schemes from each of the categories have been evaluated with respect to major distinguishing characteristics of the WiMAX MAC layer and PHY layer as specified in the IEEE 802.16d standard. Suggestions and research trends on QoS support in WiMAX networks are highlighted.

A Real Time Video Transmission Routing Protocol in Multi-Interface Multi-Channel Ad Hoc Based on Queue Length and Delay Contraint

2012 ◽  
Vol 241-244 ◽  
pp. 2354-2361
Author(s):  
Ling Song ◽  
Tao Shen Li ◽  
Yan Chen
Keyword(s):  
Real Time ◽  
Routing Protocol ◽  
Video Transmission ◽  
Ad Hoc ◽  
Signal To Noise Ratio ◽  
Link Quality ◽  
Channel Switching ◽  
Quality Metric ◽  
Switching Algorithm

Real-time video transmission demands tremendous bandwidth, throughput and strict delay. For transmitting real-time video in the multi-interface multi-channel Ad hoc, firstly, we applied multi-interface multi-channel extension methods to the AOMDV (Ad-hoc On-demand Multipath Distance Vector) routing protocol, and improved extant channel switching algorithm, called MIMC-AOMDV (Multi-Interface Multi-Channel AOMDV) routing protocol. Secondly, we proposed video streaming delay QoS(Quality of Service) constraint and link-quality metrics, which used the multi interface queue’s total used length to get QMMIMC-AOMDV (Quality metric MIMC -AOMDV) routing protocol. The simulations show that the proposed QMMIMC-AOMDV can reduce the frame delay effectively and raise frame decodable rate and peak signal to noise ratio (PSNR), it is more suitable for real-time video streams.

Toward Distributed QoS Driven Wireless Messaging Infrastructure

2012 ◽  
pp. 377-391
Author(s):  
Souheil Khaddaj ◽  
Bippin Makoond
Keyword(s):  
Quality Of Service ◽  
Real Time ◽  
Video Transmission ◽  
Voice Over Ip ◽  
The Internet ◽  
Banking Services ◽  
Quality Aspects ◽  
Mobile Accessibility ◽  
Mobile Market

The Telecoms market is demanding more services which involve an increased mobile accessibility to the Internet, real time video transmission, real time games, Voice over IP (VOIP), and business critical transactions such as billing transactions and banking services. Meeting these challenges requires the mobile operators to change the way they design their telephony and messaging systems. As the mobile market moves to become more service centric, rather than technology centric, Quality of Service (QoS) has grown to become imperative, since in the Telecoms innovative services are very often short lived, where the quality aspects of a system and the provided services contribute as key differentiators. Thus, the main focus of this chapter is based around the QoS issues which have led to the consideration of a distributed messaging model to address the challenges faced in the Telecoms industry.

scholarly journals Dynamic and adaptive multi-path routing algorithm based on software-defined network

2018 ◽  
Vol 14 (10) ◽  
pp. 155014771880568 ◽  
Author(s):  
Wu Jiawei ◽  
Qiao Xiuquan ◽  
Nan Guoshun
Keyword(s):  
Quality Of Service ◽  
Real Time ◽  
Video Transmission ◽  
Service Providers ◽  
Routing Algorithm ◽  
Global Network ◽  
Software Defined Network ◽  
Network State ◽  
Computational Overhead

Recently, there has been a surge of the video services over the Internet. However, service providers still have difficulties in providing high-quality video streaming due to the problem of scheduling efficiency and the wide fluctuations of end-to-end delays in the existing multi-path algorithms. To solve these two problems affecting video transmission quality, networks are expected to have the capability of dynamically managing the network nodes for satisfying quality-of-service requirements, which is a challenging issue for media streaming applications. Against this changing network landscape, this article proposes a dynamic and adaptive multi-path routing algorithm under three constraints (packet loss, time delay, and bandwidth) that are based on software-defined network for centralized routing computations and real-time network state updating in multimedia applications. Compared with related multi-path routing proposals, dynamic and adaptive multi-path routing makes efficient use of the latest global network state information achieved by the OpenFlow controller and calculates the optimal routes dynamically according to the real-time status information of the link. Moreover, our proposed algorithm can significantly reduce the computational overhead of the controller while completing a fine-grained flow balance. Experimental results show that dynamic and adaptive multi-path routing significantly outperforms other existing scheduling approaches in achieving a 35%–70% improvement in quality-of-service.

scholarly journals ARQ-Aware Scheduling and Link Adaptation for Video Transmission over Mobile Broadband Networks

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Victoria Sgardoni ◽  
David R. Bull ◽  
Andrew R. Nix
Keyword(s):  
Real Time ◽  
Error Rate ◽  
Video Transmission ◽  
Mobile Station ◽  
Transmission Efficiency ◽  
Packet Error Rate ◽  
Mobile Wimax ◽  
Mobile Broadband ◽  
Channel Errors ◽  
Correlated Channel

This paper studies the effect of ARQ retransmissions on packet error rate, delay, and jitter at the application layer for a real-time video transmission at 1.03 Mbps over a mobile broadband network. The effect of time-correlated channel errors for various Mobile Station (MS) velocities is evaluated. In the context of mobile WiMAX, the role of the ARQ Retry Timeout parameter and the maximum number of ARQ retransmissions is taken into account. ARQ-aware and channel-aware scheduling is assumed in order to allocate adequate resources according to the level of packet error rate and the number of ARQ retransmissions required. A novel metric, namely,goodput per frame, is proposed as a measure of transmission efficiency. Results show that to attain quasi error free transmission and low jitter (for real-time video QoS), only QPSK 1/2 can be used at mean channel SNR values between 12 dB and 16 dB, while 16QAM 1/2 can be used below 20 dB at walking speeds. However, these modes are shown to result in low transmission efficiency, attaining, for example, a total goodput of 3 Mbps at an SNR of 14 dB, for a block lifetime of 90 ms. It is shown that ARQ retransmissions are more effective at higher MS speeds.

scholarly journals An Adaptive Framework for Real-Time ECG Transmission in Mobile Environments

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Kyungtae Kang
Keyword(s):  
Real Time ◽  
Perceived Quality ◽  
Wireless Channel ◽  
Ecg Monitoring ◽  
Mobile Environment ◽  
Reconstructed Signal ◽  
Channel Conditions ◽  
Adaptive Framework ◽  
Ecg Data

Wireless electrocardiogram (ECG) monitoring involves the measurement of ECG signals and their timely transmission over wireless networks to remote healthcare professionals. However, fluctuations in wireless channel conditions pose quality-of-service challenges for real-time ECG monitoring services in a mobile environment. We present an adaptive framework for layered coding and transmission of ECG data that can cope with a time-varying wireless channel. The ECG is segmented into layers with differing importance with respect to the quality of the reconstructed signal. According to this observation, we have devised a simple and efficient real-time scheduling algorithm based on the earliest deadline first (EDF) policy, which decides the order of transmitting or retransmitting packets that contain ECG data at any given time for the delivery of scalable ECG data over a lossy channel. The algorithm takes into account the differing priorities of packets in each layer, which prevents the perceived quality of the reconstructed ECG signal from degrading abruptly as channel conditions worsen, while using the available bandwidth efficiently. Extensive simulations demonstrate this improvement in perceived quality.

An Improved Cross-Layer Architecture for H.264/SVC Transmission over IEEE 802.11e Networks

2013 ◽  
Vol 303-306 ◽  
pp. 1933-1938
Author(s):  
Yun Feng Wang ◽  
Hong Bing Ma
Keyword(s):  
Video Transmission ◽  
Scalable Video Coding ◽  
Video Quality ◽  
Wireless Channel ◽  
Ieee 802.11E ◽  
Cross Layer ◽  
Cross Layer Design ◽  
Application Layer ◽  
Mapping Mechanism

As an extension to H.264, Scalable Video Coding (SVC) provides three types of scalability, which makes it more suitable for the video transmission over wireless networks. IEEE 802.11e introduces EDCA mechanism to support Quality of Service (QoS). In this paper, a scheme, based on cross-layer design between application layer and MAC layer, is proposed to improve SVC transmission over 802.11e networks. With optimized mapping mechanism and queue management, the approach has taken the SVC video priority and network congestion status into consideration. Simulation demonstrates the effectiveness of the algorithm. The experimental results show that our approach can get full use of the limited wireless channel resources, by which SVC packets with high priority can obtain better protection, thus the decoding video quality can be significantly improved.

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