Forward Error Correction Mechanism Research Articles

Mobile 4K / 2K / HD video streaming supported by real-time FEC raptorQ codes

With the growth of packet-switch networks in the mobile consumer electronics market, fountain codes are coming to play an increasingly important role as they allow high packet loss rates while still supporting high QoS. This is particularly critical for video streaming in multimedia delivery on moving handheld mobile consumer devices. A powerful forward error-correction mechanism is the fountain coding scheme implemented by RaptorQ codes, defined over GF(256), whose decoding algorithms are very complex from a computational perspective, but highly suitable for parallelization. With multimedia delivery for handheld consumer electronics in mind, this paper proposes several decoding schemes for embedded mobile SoCs, exploiting both the parallel potential of the GPU and CPU, sharing a common memory space. The OpenCL and OpenMP frameworks are used to exploit both accelerators for the roles of matrix multiplication and inversion that comprise the bulk of computation in RaptorQ decoding. Reported results indicate low-power requirements within the range of typical handheld consumer devices (1.5~2.4W) for data processing rates of dozens of Mbit/s that are fully within the real-time requirements of HD, 2K and 4K coded video streaming resolutions and beyond.

Efficient AL-FEC Mechanism Aided by Navigation Systems for SOTM Systems

Satellite communications on the move (SOTM) systems are useful for many commercial and military applications, because they support network connectivity and mobility in very large geographical areas. However, SOTM systems suffer from channel blockage because of pointing errors of the antenna and shadowing by obstructions. This channel blockage reduces the network throughput. In this paper, we address a fully reliable application layer forward error correction (AL-FEC) mechanism for SOTM systems to enhance the network throughput. In particular, we propose an acknowledgement exchange protocol to ensure the reliability of the end-to-end data transfer as well as a transmission control scheme aided by navigation systems to enhance the resource efficiency in the AL-FEC mechanism. The proposed AL-FEC mechanism can predict channel blockage by utilizing navigation systems. The proposed mechanism then makes it possible to suspend the data transmission for the duration of the channel blockage. We also theoretically derive the file transfer time, the goodput, and the resource efficiency to justify the effectiveness of the proposed AL-FEC mechanism. The performance results show that the proposed AL-FEC mechanism can significantly enhance the goodput as compared with that of transmission control protocol. Furthermore, the resource efficiency is improved with the aid of the navigation systems.

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.

Joint Network Channel Fountain Schemes for Machine-Type Communications Over LTE-Advanced

Machine-type communications (MTC) also known as machine-to-machine (M2M) communications over long-term evolution-advanced (LTE-A) networks with ubiquitous coverage and global Internet working is expected to constitute a significant part of the Internet of Things (IoT) paradigm. However, there are paramount challenges and active research activities to accommodate M2M communications over LTE-A network without sacrificing the quality of human-based services. Among them the performance of M2M communications in LTE advanced relay network has not been fully investigated yet. In particular, LTE/LTE-A uses turbo codes as the forward error correction (FEC) mechanism in the physical layer. Since turbo codes are fixed rate codes, an automatic repeat request (ARQ) is sent to the sender when the receiver fails to recover complete packet that results in packet failure and waste of radio resources. In this paper, to combat the detrimental effects of wireless fading channel, we propose a set of joint network and fountain coding (JNFC) schemes for reliable uplink transmission between M2M devices and evolved NodeB (eNB). Specially, we consider clustered heterogeneous M2M networks, where cluster heads (CHs) transmit to eNB directly or by the help of relays. Numerical results are presented to demonstrate the performance of the proposed schemes over type I and type II relay-enhanced LTE-A networks. It shows that in type I relay enhanced networks, JNFC with space time block codes (JNFC-STBC) outperforms the direct transmission with relays (DTRs) and in type II enhanced networks, JNFC with robust soliton distribution (JNFC-RSD) outperforms JNFC with random linear network coding (JNFC-RLNC) in a variety of metrics.

Centralised Enhanced forward Error Correction Mechanism on the Contention Window to Improve the Transmission Quality in Vehicular AD Hoc Networks

Background: Vanet the recent emerging technology in the recent industry has grabbed the attention with advanced techniques and extricate framework of sophisticated equipments. Initially absence of an infrastructure in this network has communication constraints for the nodes involved therein. Adding to this the dynamic topology makes the network more vulnerable for potential targets of security and reliability of data diffusion within these nodes. The communication standard i.e. 802.11p have some optional channel rejection in the Orthogonal Frequency Division Multiplexing in the Physical layer which motivated to work on the reliability methods of data dissemination. Methods: To start with the hidden terminal issues of these networks have to be addressed which can be resolved by frame capture. This frame capture quality in turn is determined by the Contention window of the Physical layer. Hence an adaptive mechanism that involves forward Error correction (AFEC) which helps to overcome packet losses in an efficient way in midst of channel fluctuation, burst packet loss. The results are simulated in NS2 (2.34) with static packet size of 512 bytes. Findings: The experimental results demonstrated that the FEC mechanism is more adaptive in adjusting and controlling the data redundancy across the network for static and dynamic channel fluctuations. The redundancy rate was further reduced with an adaptive technique on the Contention Window size, which had considerable effects of every transmission on the delay, through put and jitter. The centralized FEC algorithm is set on an adaptive platform where each vehicle updates its back off window size at the end of each Observation Time depending on the priority of the message received. The feasible part of this algorithm is that it can be implemented on the MAC layer, which has a Reception Module. Consequently, the proposed mechanism under various network conditions performs well in terms of QoS for emergency messages than the conventional methods for a less volume of data. Application/Improvements: The algorithm can be analyzed from a traffic scenario of two-way highway and rural areas. The progress of the work can also be carried out for multimedia messages.

English

Video transmission over the wireless network faces many challenges. The most critical challenge is related to packet loss. To overcome the problem of packet loss, Forward Error Correction is used by adding extra packets known as redundant packet or parity packet. Currently, FEC mechanisms have been adopted together with Automatic Repeat request (ARQ) mechanism to overcome packet losses and avoid network congestion in various wireless network conditions. In the current Adaptive FEC mechanism, the FEC packets are decided by the average queue length and average packet retransmission times. The Adaptive FEC mechanisms have been proposed to suit the network condition by generating FEC packets adaptively in the wireless network. However, the current Adaptive FEC mechanism has some major drawbacks such as the reduction of recovery performance which injects too many excessive FEC packets into the network. This is not flexible enough to adapt with varying wireless network condition. Therefore, the enhancement of Adaptive FEC mechanism (AFEC) known as Enhanced Adaptive FEC (Enface) has been proposed. The aim is to improve recovery performance on the current Adaptive FEC mechanism by injecting FEC packets dynamically based on varying wireless network conditions. Based on the findings, the optimal amount of FEC generated by Enface mechanism can recover high packet loss and produce good video quality An Enhanced Random Early Detection Forward Error Correction (ERED-FEC) mechanism is implemented to improve the quality of video transmissions over Wireless Local Area Networks (WLANs).

Pattern Matching Techniques for Replacing Missing Sections of Audio Streamed across Wireless Networks

Streaming media on the Internet can be unreliable. Services such as audio-on-demand drastically increase the loads on networks; therefore, new, robust, and highly efficient coding algorithms are necessary. One method overlooked to date, which can work alongside existing audio compression schemes, is that which takes into account the semantics and natural repetition of music. Similarity detection within polyphonic audio has presented problematic challenges within the field of music information retrieval. One approach to deal with bursty errors is to use self-similarity to replace missing segments. Many existing systems exist based on packet loss and replacement on a network level, but none attempt repairs of large dropouts of 5 seconds or more. Music exhibits standard structures that can be used as a forward error correction (FEC) mechanism. FEC is an area that addresses the issue of packet loss with the onus of repair placed as much as possible on the listener's device. We have developed a server--client-based framework (SoFI) for automatic detection and replacement of large packet losses on wireless networks when receiving time-dependent streamed audio. Whenever dropouts occur, SoFI swaps audio presented to the listener between a live stream and previous sections of the audio stored locally. Objective and subjective evaluations of SoFI where subjects were presented with other simulated approaches to audio repair together with simulations of replacements including varying lengths of time in the repair give positive results.

Bandwidth efficient adaptive forward error correction mechanism with feedback channel

Multimedia content is very sensitive to packet loss and therefore multimedia streams are typically protected against packet loss, either by supporting retransmission requests or by adding redundant forward error correction (FEC) data. However, the redundant FEC information introduces significant additional bandwidth requirements, as compared to the bitrate of the original video stream. Especially on wireless and mobile networks, bandwidth availability is limited and variable. In this article, an adaptive FEC (A-FEC) system is presented whereby the redundancy rate is dynamically adjusted to the packet loss, based on feedback messages from the client. We present a statistical model of our A-FEC system and validate the proposed system under different packet loss conditions and loss probabilities. The experimental results show that 57-95% bandwidth gain can be achieved compared with a static FEC approach.

Hybrid FLUTE/DASH video delivery over mobile wireless networks

ABSTRACTThis paper describes how File Delivery over Unidirectional Transport (FLUTE) and Dynamic Adaptive Streaming over Hypertext Transfer Protocol (DASH) can be used to provide mobile video streaming services over broadcast wireless networks. FLUTE is a multicast protocol for multimedia file download. In this proposal, the protocol is adapted to provide video streaming services in crowded environments. Thus, video is delivered over a single connection to all viewers, reducing the traffic in the network. FLUTE incorporates an application‐layer forward error correction (AL‐FEC) mechanism in order to improve the reliability of the broadcast communication channel. For streaming applications, AL‐FEC improves the relationship between the peak signal‐to‐noise ratio (PSNR) of the received video and the bandwidth allocated to the broadcast connection. The AL‐FEC hereby presented applies simple unequal error protection schemes to favour the download of key frames. Furthermore, the proposal is based on the same video segmentation mechanism as DASH, and therefore, clients can connect to a DASH repository to repair errors in the segments. This paper shows that FLUTE and DASH can be seamlessly integrated into a hybrid broadcast/unicast streaming technology, providing flexibility to trade off PSNR and bandwidth depending on the conditions of the mobile network. Copyright © 2014 John Wiley & Sons, Ltd.

A Cross-Layer QoE-Based Approach for Event-Based Multi-Tier Wireless Multimedia Sensor Networks

Wireless Multimedia Sensor Networks (WMSNs) are attracting attention from both academic and industrial environments due to the rapid development of low-cost multimedia sensors. With the enhancement of the multimedia content captured by multimedia devices, WMSNs play an important role in pervasive and ubiquitous systems. The multimedia content in these networks has the potential to enhance the level of collected information, by enlarging the range of coverage, and enabling multi-view support. In the case of WMSN applications, the multi-tier network architecture has proved to be more beneficial than single-tier architecture in terms of energy-efficiency, scalability, functionality and reliability. In this context, a multimedia event detection application is a promising application for multi-tier WMSNs, where the lower-tier nodes detect an event occurrence by means of scalar measurements, and the higher-tier nodes will be woken up to send real-time video flows from the event area. The transmission of multimedia content requires a certain quality level from the user's perspective, while energy consumption and network overhead should be minimized. Among the existing mechanisms for improving video transmissions, application-level Forward Error Correction (FEC) is regarded as a suitable solution to improve video quality level from the user´s standpoint. In this work, the authors propose an adaptive cross-layer approach, which includes a Quality of Experience (QoE)-aware FEC mechanism for WMSNs by generating redundant packets, based on frame importance from user's experience. Additionally, the aothors introduce a multi-tier routing protocol to select the best route to transmit multimedia data. According to the simulation results, the proposed cross-layer approach achieved high video quality level with reduced transmission of redundant packets, which will bring many benefits to a resource-constrained system.

A comparative study of packet combining based error recovery schemes for wireless networks

To provide reliable communications in wireless environments, two fundamental error control mechanisms, automatic repeat request (ARQ) and forward error correction (FEC) are proposed. However, the ARQ mechanism may suffer frequent retransmissions and the FEC mechanism incurs bandwidth overhead. To reduce the number of retransmissions and support efficient correction, previous studies have proposed numerous packet combining based error recovery schemes. This study investigates the recovery performance of three packet combining based error recovery schemes, including the extended ARQ (EARQ), the merge strategy in the simple packet combining (SPaC–M), and the destination packet (DPC) schemes through the mathematical analysis and simulations. Results present that the EARQ outperforms the SPaC–M and the DPC in recovery speed in case of a large packet length and a high bit error rate. However, the EARQ is not suggested if the space overhead is the major consideration.

An enhanced structure of layered forward error correction and interleaving for scalable video coding in wireless video delivery

The forward error correction (FEC) mechanism adds redundancy to the original information and uses this redundancy to recover the errors in, or loss of, the original information. Compared with the automatic retransmission request (ARQ) approach, FEC reduces delay but utilizes more bandwidth resources. To enhance video transmission over wireless networks, another mechanism, enhanced adaptive FEC (EAFEC), has been recently presented. According to the throughput and wireless channel state, EAFEC dynamically determines the length of the redundancy and reduces the transmission of unnecessary redundancy to achieve the efficient utilization of wireless networking resources. To further enhance the efficiency of EAFEC, we propose an enhanced structure, adaptive and interleaving FEC (AIFEC) using the features of FEC. Our proposed AIFEC scheme not only dynamically provides different protection strengths for video information of different priority levels based on the throughput and wireless channel state, but also significantly improves the recovery rate for consecutive packet loss.

An Access Point-Based FEC Mechanism for Video Transmission Over Wireless LANs

Forward Error Correction (FEC) is one of the most common means of performing packet error recovery in data transmissions. FEC schemes typically tune the FEC rate in accordance with feedback information provided by the receiver. However, the feedback and FEC rate calculation processes inevitably have a finite duration, and thus the FEC rate implemented at the sender may not accurately reflect the current state of the network. Thus, this paper proposes an Enhanced Random Early Detection Forward Error Correction (ERED-FEC) mechanism to improve the quality of video transmissions over Wireless Local Area Networks (WLANs). In contrast to most FEC schemes, the FEC redundancy rate is calculated directly at the Access Point (AP). Moreover, the redundancy rate is tuned in accordance with both the wireless channel condition (as indicated by the number of packet retransmissions) and the network traffic load (as indicated by the AP queue length). The experimental results show that the proposed ERED-FEC mechanism achieves a significant improvement in the video quality compared to existing FEC schemes without introducing an excessive number of redundant packets into the network.

Adaptive error control in wireless sensor networks under harsh smart grid environments

PurposeHigh packet error rates and variable link capacity due to harsh electric power system environments make reliable communication a challenging task for WSN in smart grid. Therefore, to increase network reliability and hence, to improve smart grid system performance, there is an urgent need for reliable communication protocols. The purpose of this paper is to propose an Adaptive Forward Error Correction (AFEC) mechanism for different smart grid environments, including 500 kV outdoor substation and underground transformer vaults, to address these challenges.Design/methodology/approachThis paper presents the comparative performance evaluations of proposed AFEC mechanism for different smart grid environments. Simulation experiments have been performed by extending the ns‐2 network simulator. It also introduces existing and potential smart grid applications, research challenges, and opportunities of smart grid.FindingsComparative performance evaluations show that the proposed AFEC mechanism achieves high communications reliability without causing unnecessary network overhead. Also the advantages of existing smart grid applications have been presented.Originality/valueThe paper shows that high communications reliability without causing unnecessary network overhead has been achieved. Also comprehensive reviews of WSN smart grid applications have been presented.

Evaluation of the MDC and FEC over the quality of service and quality of experience for video distribution in ad hoc networks

Mobile ad hoc networks (MANETs) offer an excellent scenario for deploying communication applications because of the connectivity and versatility of this kind of networks. In contrast, the topology is usually extremely dynamic causing high rate of packet loss, so that ensuring a specific Quality of Service (QoS) for real-time video services becomes a hard challenge. In this paper, we evaluate the effect of using Multiple Description Coding (MDC) and Forward Error Correction (FEC) techniques for improving video quality in a multimedia content distribution system. A hybrid architecture using fixed and wireless ad hoc networks is proposed, which enables the use of multipoint-to-point transmission. MDC and FEC mechanisms can be combined with multipath transmission to increase the network efficiency and recover lost packets, improving the overall Quality of Experience (QoE) of the receiver. Simulations have been analyzed paying attention to objective parameters (Peak Signal to Noise Ratio, Packet Delivery Ratio, Decodable Frame Rate and interruptions) and subjective parameters. Results show that MDC increases the probability of packet delivery and FEC is able to recover lost frames and reduce video interruptions in moderate mobility scenarios, resulting in the improvement of video quality and the final user experience.

DP-FEC: Dynamic Probing FEC for High-Performance Real-Time Interactive Video Streaming

High-quality and high-performance real-time interactive video streaming requires both keeping the highest data transmission rate and minimizing data packet loss to achieve the best possible streaming quality. TCP-friendly rate control (TFRC) is the most widely recognized mechanism for achieving relatively smooth data transmission while competing fairly with TCP flows. However, because its data transmission rate depends largely on packet loss conditions, high-quality real-time streaming suffers from a significant degradation of streaming quality due to both a reduction in the data transmission rate and data packet losses. This paper proposes the dynamic probing forward error correction (DP-FEC) mechanism that is effective for high-quality real-time streaming to maximize the streaming quality in a situation in which competing TCP flows pose packet losses to the streaming flow. DP-FEC estimates the network condition by dynamically adjusting the degree of FEC redundancy while trying to recover lost data packets. It effectively utilizes network resources and adjusts the degree of FEC redundancy to improve the playback quality at the user side while minimizing the performance impact of competing TCP flows. We describe the DP-FEC algorithm and evaluate its effectiveness using an NS-2 simulator. The results show that by effectively utilizing network resources, DP-FEC enables to retain higher streaming quality while minimizing the adverse condition on TCP performance, thus achieving TCP friendliness.

Forward-Looking Forward Error Correction Mechanism for Video Streaming Over Wireless Networks

Video streaming over wireless network poses a great challenge because the high packet error rate usually decreases the quality of video streaming. Forward error correction (FEC) mechanism is generally used to protect the video quality. However, the recovery performance of the FEC mechanism decreases when burst packet loss is larger than the added FEC redundant packets. In this paper, the forward-looking forward error correction (FL-FEC) mechanism is proposed to recover lost packets for video streaming over wireless networks. The FL-FEC mechanism recovers not only the lost packet from its FEC block but also the previous FEC block from the recovered packet, repeating the recovery procedure until recovering the first FEC block. If the play-out buffer at the receiver is large, the FL-FEC mechanism can execute a chain of recovery procedures to ultimately recover all lost packets without any negative impact on application performance. The FL-FEC mechanism selects non-continuous source packets in previous FEC blocks to generate FEC redundancy with the FEC block. Hence, the FL-FEC mechanism can significantly disperse burst packet loss into different FEC blocks. The FL-FEC mechanism uses an analytical model to decide the number of FEC redundant packets in order to obtain the minimum recovery overhead. The FL-FEC mechanism is tested to show the benefits of high recovery performance and low recovery overhead in improving the peak signal-to-noise ratio and the decodable frame rate of video streaming over wireless networks.

Cost optimization of MBSFN and PTM transmissions for reliable multicasting in LTE networks

Long Term Evolution (LTE) systems have been specified and designed to accommodate small, high performance, power-efficient, end-user devices. The evolved Multimedia Broadcast/Multicast Service (e-MBMS) feature is introduced by the 3rd Generation Partnership Project (3GPP) as a complement to the existing MBMS service in order to accommodate multicast groups that are interested in receiving the same data. MBMS service is provided by MBMS over a Single Frequency Network (MBSFN) and/or Point-To-Multipoint (PTM) transmission methods. One of the challenges of MBMS is the complete error recovery of the transmitted files, a matter of great importance since the distribution of binary data must result in 100% error-free download. To fulfill this tight requirement, Forward Error Correction (FEC) mechanism has been proposed by 3GPP. In this work, we investigate the reliable multicasting by introducing a transmission method that combines the advantages of MBSFN and PTM transmission methods. We compare several FEC-based file recovery methods and evaluate them against various network parameters in a realistic simulation environment. The comparison is based on a cost-oriented analysis of MBMS service that takes into account the transmission cost over all the interfaces and nodes of the LTE architecture. The simulation results are performed with the aid of a new simulation tool and show that the performance of the file repair schemes depend on the network configuration.

안정적 Wi-Fi 방송 서비스를 위한 무선 랜 전송 특성 분석

무선 랜 기술을 방송 분야에 응용하기 위해서는 IEEE 802.11 방송 패킷에 대한 이해가 필요하다. 현재 IEEE 802.11 방송 패킷 전송 기술은 Unicast 패킷 전송 기술에 비해 컨텐츠 전달의 신뢰성을 보장 할 수 없다는 단점이 있다. 이러한 무선 랜 방송 기술의 손실률 제어를 위한 기법으로 FEC가 주로 사용되고 있다. 무선 랜 방송 기술에 FEC 기법을 활용함에 있어서 핵심은 복구를 위한 여분의 패킷 양을 결정하는 것이다. 이에 본 논문은 먼저 다중 무선 랜 전송률-(1-54Mbps) 이 지원되는 방송 테스트베드를 구성하였다. 그리고 방송 패킷의 길이, 무선랜 전송률, 주변 환경에 따른 손실률을 구하고 손실률을 최소화 할 수 있는 인자들의 값을 도출 하였다. 나아가 구해진 손실률을 이용하여 FEC 여분 패킷 양을 결정하였다. To apply Wi-Fi technique to the Broadcast field, we have to study features of IEEE 802.11 Broadcast packet. IEEE 802.11 Broadcast technique cannot guarantee successful packet delivery than IEEE 802.11 Unicast. A promising solution to this problem is the use of FEC(Forward Error Correction) mechanisms. However, the adjustment of the FEC redundancy rate is not a trivial issue due to the dynamic wireless environment. In order to explore the above issues we conducted an experimental study of the packet loss behavior of the IEEE 802.11g protocol. In order to study, we implemented a broadcast test bed. Based on the experimental results, we provide guidelines on wireless lan parameters(packet size, transmission rate(11g), background traffic). From this experimental study, we provide FEC redundancy rate.

Performance evaluation of AL-FEC LDPC codes for push content applications in wireless unidirectional environments

FEC (Forward Error Correction) mechanisms improve IP content transmission reliability through the recovery of packets lost in transmission. Opposite to ARQ (Automatic Repeat Request), FEC mechanisms are especially suited to unidirectional environments or to multicast environments where multiple receivers perceived different channel losses, thus making difficult the implementation of mechanisms based on feedback information. Among the different types of FEC codes, this paper presents a thorough performance evaluation of LDPC (Low Density Parity Check) codes, based on an implementation developed by the authors, according to the specifications defined by RFC 5170 for the usage of LDPC codes by push content applications based on the FLUTE protocol. LDPC codes provide a good trade-off between performance and complexity, hence, they are appropriate for mobile applications. Contributions of this paper include tests conducted with commercial mobile phones connected to the push content download server over a Wi-Fi network. The evaluation highlights the advantages of using packet level FEC encoding in file transmission over unidirectional networks and provides with a comparison between two kinds of LDPC structures: Staircase and Triangle. This is accomplished by calculating the inefficiency ratio of these LDPC structures in different environments. Results show that the implemented LDPC codes can provide inefficiency ratios close to one when the different coding parameters (as the code rate or the number of blocks) are configured to an optimal value that depends on the packet loss rate.