A Prototype Modelling of Ebers for Video Transmission in Wireless Adhoc Network

Provisioning of video streaming over ad hoc wireless networks exhibits challenges associated with high packet loss rates and are delay sensitive Excessive packet loss can cause significant degradation in quality of video perceived by users of real-time video applications The recent studies suggest that Forward Error Correction FEC is a good technique for decreasing the negative impact of packet loss on video quality in error control scheme This paper introduces an Estimation based Error Reduction Scheme EBERS to support video communication in ad hoc wireless networks The EBERS considers a frame estimation parameter to support varied bandwidths and attain the delay requirements to support video communication It is also responsible for improvising the QoS offered The EBERS considers layered and embodies distortion limiting features owing to which reduced forward error correction is achieved thus obtaining reduced frame errors transmission errors and retransmission of frames Thereby obtaining high degree of quality of service QoS The comparative study conducted proves the efficiency of the EBERS scheme over the existing mechanism

Adaptive protection scheme for MVC-encoded stereoscopic video streaming in IP-based networks

We present an adaptive unequal error protection (UEP) strategy built on the 1-D interleaved parity Application Layer Forward Error Correction (AL-FEC) code for protecting the transmission of stereoscopic 3D video content encoded with Multiview Video Coding (MVC) through IP-based networks. Our scheme targets the minimization of quality degradation produced by packet losses during video transmission in time-sensitive application scenarios. To that end, based on a novel packet-level distortion model, it selects in real time the most suitable packets within each Group of Pictures (GOP) to be protected and the most convenient FEC technique parameters, i.e., the size of the FEC generator matrix. In order to make these decisions, it considers the relevance of the packet, the behavior of the channel, and the available bitrate for protection purposes. Simulation results validate both the distortion model introduced to estimate the importance of packets and the optimization of the FEC technique parameter values

A Proactive Forward Error Control Scheme for Mobile WiMAX Communication

The IEEE 802.16 standard, also known as WiMAX, has yet to prove its effectiveness when the end terminals are not static and free to move at vehicular speeds. High bit error rate caused by multipath fading at high vehicular speeds, is the key reason for low throughput at high speeds. Standard error control mechanisms like transmission control protocol (TCP) and forward error correction (FEC) have limited impact on the overall throughput at vehicular speeds. In this paper, we propose a proactive FEC scheme that adjusts the FEC code size based on the estimated bit error rate at various vehicular speeds. We show a mathematical model to estimate the bit error rate in WiMAX communication. We then propose a FEC scheme to proactively compute the FEC code size. We simulated the proposed scheme for a centralized video surveillance system in a public train where the train is the mobile node and sends real-time video data to the base stations. The results show that the proposed scheme achieves significantly higher throughput and lower jitter compared to existing schemes

An Adaptive Fuzzy based FEC Algorithm for Robust Video Transmission over Wireless Networks

Forward Error Correction (FEC) is a commonly adopted mechanism to mitigate packet loss/bit error during real-time communication. An adaptive, Fuzzy based FEC algorithm to provide a robust video quality metric for multimedia transmission over wireless networks has been proposed to optimize the redundancy of the generated code words from a Reed-Solomon encoder and to save the bandwidth of the network channel. The scheme is based on probability estimations derived from the data loss rates related to the recovery mechanism at the client end. By applying the adaptive FEC, the server uses the reports to predict the next network loss rate using a curve-fitting technique to generate the optimized number of redundant packets to meet specific residual error rates at the client end. Simulation results in the cellular system show that the video quality is massively adapted to the optimized FEC codes based on the probability of packet loss and packet correlation in a wireless environment

Distributed rate-distortion optimization for rateless coded scalable video

ABSTRACT Recent advances in forward error correction and scalable video coding enable new approaches for robust, distributed streaming in Mobile Ad Hoc Networks (MANETs). This work presents an approach for distribution of real time video by different uncoordinated peerto-peer relay or source nodes in an overlay network on top of a MANET. The approach proposed here allows for distributed, ratedistortion optimized transmission-rate allocation for competing scalable video streams at relay nodes in the overlay network. Furthermore the approach has the desirable feature of path/source diversity for enhancing reliability in connectivity to serving nodes. Signaling overhead within the overlay network is kept at a minimum, since optimizations are done at relay nodes and clients rather than at servers

Reliable Transmission of MPEG-2 VBR Video Streams over New Network Adaptation and ATM Adaptation Layers

This paper adresses the transmission of VBR MPEG-2 video streams on top of both Network Adaptation (NAL) and ATM Adaptation Layers (AAL) for real-time multimedia applications. The NAL, specific to MPEG-2, provides a selective data protection mechanism based on syntactic criteria. The AAL provides a reliable transmission by applying per-cell sequence numbering combined with a selective Forward Error Correction (FEC) mechanism based on Burst Erasure codes. Studies carried out with Constant Bit Rate (CBR) video streams showed improvements in terms of network performance evaluated by the cell loss ratio (CLR) as well as in terms of user perceived quality compared to the performance obtained with AAL5 under the same network conditions. This paper proposes improvements at the NAL and presents the results obtained for the transmission of Variable Bit Rate (VBR) video streams. To evalute the impact of cell losses at the application level, we apply a perceptual quality measure to the decoded MPEG-2 sequences which allows us to evaluate performance at the user level

Real-time compressed video transmission across the common data link

The advances in high speed computer networks and digital communication techniques have enabled the rapid and extensive dissemination of information throughout the modern defense infrastructure. One of the challenges in networking today is real-time dissemination of information. This thesis proposes a solution for a specific aspect of this challenge, namely, the transmission of real-time compressed video data across the Common Data Link (CDL), a high-speed military data link designed to operate in high error environments. Current research is primarily focused on the transmission of real- time data across low-error links. This thesis proposes, simulates, and analyzes a mechanism which guarantees that (1) delay bounds are met for real-time flows despite network overload and (2) a minimum acceptable image quality is maintained despite the presence of highly correlated errors. These highly correlated errors are characteristic of the type of electromagnetic jamming likely to be encountered by the CDL. This mechanism consists of four fundamental requirements: (1) a hierarchical image compression scheme, (2) rate control at the source, (3) bandwidth allocation within all encountered network nodes, and (4) dynamic forward error correction. The proposed solution is modeled in the OPNET simulation environment, and the validity and feasibility of the mechanism are verified. In addition, the simulation is interfaced with a compression/decompression algorithm running in MATLAB to enable the subjective analysis of actual images before and after transmission in various jamming scenarios. The results demonstrate the effectiveness of the proposed solution in meeting delay guarantees and maintaining image quality.http://archive.org/details/realtimecompress109457522U.S. Navy (U.S.N.) author

Error Resilient Multipath Video Delivery on Wireless Overlay Networks

Real time applications delivering multimedia data over wireless networks still pose many challenges due to high throughput and stringent delay requirements. Overlay networks with multipath transmission is the promising solution to address the above problems. But in wireless networks the maintenance of overlay networks induce additional overheads affecting the bulky and delay sensitive delivery of multimedia data. To minimize the overheads, this work introduces the Error Compensated Data Distribution Model (ECDD) that aids in reducing end to end delays and overheads arising from packet retransmissions. The ECDD adopts mTreebone algorithm to identify the unstable wireless nodes and construct overlay tree. The overlay tree is further split to support multipath transmissions. A sub packetization mechanism is adopted for multipath video data delivery in the ECDD. A forward error correction mechanism and sub-packet retransmission techniques adopted in ECDD enables to reduce the overhead and end to end delay. The simulation results presented in this paper prove that the ECDD model proposed achieves lower end to end delay and outperforms the existing models in place. Retransmission requests are minimized by about 52.27% and bit errors are reduced by about 23.93% than Sub-Packet based Multipath Load Distribution