Performance Of Forward Error Correction Research Articles

A comparison analysis on forward error correction technology: a future perspective for GNSS

PurposeThe main aim of this study is to elaborately examine the error correction technology for global navigation satellite system (GNSS) navigation messages and to draw a conceptual decision support framework related to the modernization of the GNSS and other systems.Design/methodology/approachThe extensive simulation model developed in Matrix Laboratory (MATLAB) is used to evaluate the performance of forward error correction (FEC) codes such as Hamming, Bose–Chaudhuri–Hocquenghem, convolutional, turbo, low-density parity check (LDPC) and polar codes under different levels of noise.FindingsThe performance and robustness of the aforementioned algorithms are compared based on the bit length, complexity and execution time of the GNSS navigation message. In terms of bit error rate, LDPC coding exhibits more ability in the robustness of the navigation message, while polar code gives better results according to the execution time.Practical implicationsIn view of future new GNSS signals and message design, the findings of this paper may provide significant insight into navigation message modernization and design as an important part of GNSS modernization.Originality/valueTo the best of the authors’ knowledge, this is the first study that conducts a direct comparison of various FEC algorithms on GNSS navigation message performance against noise, taking into consideration turbo and newly developed polar codes.

Enhancing BER Performance Limit of BCH and RS Codes Using Multipath Diversity

Modern wireless communication systems suffer from phase shifting and, more importantly, from interference caused by multipath propagation. Multipath propagation results in an antenna receiving two or more copies of the signal sequence sent from the same source but that has been delivered via different paths. Multipath components are treated as redundant copies of the original data sequence and are used to improve the performance of forward error correction (FEC) codes without extra redundancy, in order to improve data transmission reliability and increase the bit rate over the wireless communication channel. For a proof of concept Bose, Ray-Chaudhuri, and Hocquenghem (BCH) and Reed-Solomon (RS) codes have been used for FEC to compare their bit error rate (BER) performances. The results showed that the wireless multipath components significantly improve the performance of FEC. Furthermore, FEC codes with low error correction capability and employing the multipath phenomenon are enhanced to perform better than FEC codes which have a bit higher error correction capability and did not utilise the multipath. Consequently, the bit rate is increased, and communication reliability is improved without extra redundancy.

BCH Codes for Coherent Star DQAM Systems with Laser Phase Noise

AbstractCoherent optical systems have relatively high laser phase noise, which affects the performance of forward error correction (FEC) codes. In this paper, we propose a method for selecting Bose–Chaudhuri–Hocquenghem (BCH) codes for coherent systems with star-shaped constellations and

Low-complexity BCH codes with optimized interleavers for DQPSK systems with laser phase noise

The presence of high phase noise in addition to additive white Gaussian noise in coherent optical systems affects the performance of forward error correction (FEC) schemes. In this paper, we propose a simple scheme for such systems, using block interleavers and binary Bose---Chaudhuri---Hocquenghem (BCH) codes. The block interleavers are specifically optimized for differential quadrature phase shift keying modulation. We propose a method for selecting BCH codes that, together with the interleavers, achieve a target post-FEC bit error rate (BER). This combination of interleavers and BCH codes has very low implementation complexity. In addition, our approach is straightforward, requiring only short pre-FEC simulations to parameterize a model, based on which we select codes analytically. We aim to correct a pre-FEC BER of around $$10^{-3}$$10-3. We evaluate the accuracy of our approach using numerical simulations. For a target post-FEC BER of $$10^{-6}$$10-6, codes selected using our method result in BERs around 3$$\times $$× target and achieve the target with around 0.2 dB extra signal-to-noise ratio.

A two-level Markov model for packet loss in UDP/IP-based real-time video applications targeting residential users

The packet loss characteristics of Internet paths that include residential broadband links are not well understood, and there are no good models for their behaviour. This complicates the design of real-time video applications targeting home users, since it is difficult to choose appropriate error correction and concealment algorithms without a good model for the types of loss observed. Using measurements of residential broadband networks in the UK and Finland, we show that existing models for packet loss, such as the Gilbert model and simple hidden Markov models, do not effectively model the loss patterns seen in this environment. We present a new two-level Markov model for packet loss that can more accurately describe the characteristics of these links, and quantify the effectiveness of this model. We demonstrate that our new packet loss model allows for improved application design, by using it to model the performance of forward error correction on such links.

Performance Analysis of IEEE 802.16d using Forward Error Correction

Problem statement: Worldwide Interoperability for Microwave Access is the broadband wireless technology for terrestrial broadcast services in Metropolitan Area Networks. This BWA technology is based on Orthogonal Frequency Division Multiplex (OFDM) technology and considers the radio frequency range up to 2-11 GHz and 10-66 GHz. The objective of this research work is the performance analysis of AWGN, SUI-1 and SUI-2 fading channels in IEEE802.16d using FEC to improving BER at different SNR under QPSK digital modulation technique. Approach: Channel coding part is composed of three steps randomization, Forward Error Correction (FEC) and interleaving. FEC is done in two phases through the outer Reed Solomon (RS) and inner Convolutional Code (CC). The implementation and analysis will be made on using MATLAB simulation. Results: In this analysis the Bit Error Rate under QPSK modulation technique over AWGN, SUI-1 and SUI-2 fading channel with encoder for a SNR value of 5dB but in the case of without encoder is found SNR value of 9dB,10dB and 8dB respectively. Conclusion: It was concluded that all the three fading channel had same SNR with FEC .The optional Block Turbo Coding (BTC) can be implemented to enhance the performance of FEC.

FEC recovery performance for video streaming services over wired-wireless networks

This paper considers the packet recovery performance of forward error correction (FEC) for video streaming services over wired-wireless networks. Focusing on a wireless base station, we model it as a single-server queueing system with a Markovian service process in which the state of the server alternates between Good and Bad states. The system has two independent input processes: one is a general renewal input process and the other is a Poisson arrival process. We analyze the packet- and block-level loss probabilities to investigate the recovery performance of FEC at block level. The analysis is validated with simulation experiments driven by real traffic traces. Numerical examples show that the block-loss probability is greatly affected by the system capacity and the mean Bad-state period, and that the recovery performance of FEC deteriorates according to the fluctuation in the packet transmission rate at a wireless base station.

On Channel Capacity Estimation and Prediction for Rate-Adaptive Wireless Video

Packet drops caused by residue errors (MAC-layer errors) can severely deteriorate the wireless video quality. Prior studies have shown that this loss of quality can be circumvented by using forward error correction (FEC) to recover information from the corrupted packets. The performance of FEC encoded video streaming is critically dependent upon the choice of source and channel coding rates. In practice, the wireless channel conditions can vary significantly, thus altering the optimal rate choices. Thus, it is essential to develop an architecture which can estimate the channel capacity and utilize this estimate for rate allocation. In this paper we develop such a framework. Our contributions consist of two parts. In the first part we develop a prediction framework that leverages the received packets' signal to silence ratio (SSR) indications and MAC-layer checksum as side information to predict the operational channel capacity. In the second part, we use this prediction framework for rate allocation. The optimal rate allocation is dependent upon the channel capacity, the distribution of the (capacity) prediction error and the rate-distortion (RD) characteristics of the video source. Consequently, we propose a framework that utilizes the aforementioned statistics for RD optimal rate adaptation. We exhibit the efficacy of the proposed scheme by simulations using actual 802.11b wireless traces, an RD model for the video source and an ideal FEC model. Simulations using source RD models derived from five different popular video codecs (including H.264), show that the proposed framework provides up-to 5-dB improvements in peak signal-to-noise ratio (PSNR) when compared with conventional rate-adaptive schemes.

IEEE 802.11 MAC-Level FEC scheme with retransmission combining

In this paper, we evaluate and enhance the performance of a Forward Error Correction (FEC) scheme for IEEE 802.11 Medium Access Control (MAC). A novel retransmission combining technique is proposed to enhance the performance of the MAC-level FEC scheme.,We also identify the problem with the IEEE 802.11a physical (PHY) layer when it is used with the MAC-level FEC. A new PHY frame format, backward compatible with the original format, is proposed to resolve the problem. Finally, we analytically evaluate the error performance of the MAC-level FEC, and its enhanced performance via retransmission combining and new 802.11a PHY frame format in AWGN environment. Additionally, we present and discuss the results from simulations using TCP/UDP traffic in more realistic channel environments.

On the effects of the packet size distribution on FEC performance

For multimedia traffic like VBR video, knowledge of the average loss probability is not sufficient to determine the impact of loss on the perceived visual quality and on the possible ways of improving it, for example by forward error correction (FEC) and error concealment. In this paper we investigate how the packet size distribution affects the packet loss process, i.e., the probability of consecutive losses and the distribution of the number of packets lost in a block of packets and the related FEC performance. We present an exact mathematical model for the loss process of an MMPP + MMPP/ E r /1/ K queue and compare the results of the model to simulations performed with various other packet size distributions (PSDs), among others, the measured PSD from an Internet backbone. The results show that analytical models of the PSD matching the first three moments (mean, variance and skewness) of the empirical PSD can be used to evaluate the performance of FEC in real networks. We conclude that the exponential PSD, though it is not a worst case scenario, is a good approximation for the PSD of today’s Internet to evaluate FEC performance. We also conclude that the packet size distribution affects the packet loss process and thus the efficiency of FEC mainly in access networks where a single multimedia stream might affect the multiplexing behavior. We evaluate how the PSD affects the accuracy of the widely used Gilbert model to calculate FEC performance and conclude that the Gilbert model can capture loss correlations better if the CoV of the PSD is high.

Efficiency of Error-Control Schemes for Real-Time Wireless Applications on the Gilbert Channel

The design of a bandwidth-efficient physical layer for wireless access has always been a challenging task, due to the harsh environment, characterized by impairing phenomena such as radio interference, fading, and shadowing. With circuit switching, a bit-error rate suitable for real-time applications such as voice and video is guaranteed by adopting robust forward error correction (FEC) codes and proper power-budget margins to face fading problems. With this approach, automatic repeat request (ARQ) is used only for applications that require a much lower error rate and can tolerate high delays. The introduction of the packet technique allows the use of ARQ even for real-time traffic. We compare the efficiency of three error-recovering techniques in the presence of traffic with delay constraints, when the memory property of the wireless segment is represented by the Gilbert-Elliot channel. The techniques compared are FEC with interleaving, real-time ARQ, and erasure coding (EC). The comparisons are performed by using both analytical and simulation tools. Two new analytical models are introduced to evaluate the performance of FEC and EC. Simulation is used to validate the analytical results and to derive the performance of real-time ARQ. The numerical results show that when the channel memory increases well beyond the packet-transmission time, the performance of FEC impairs due to the limited interleaving depth, while ARQ and EC remain effective.

Performance evaluation of standard FEC in 40 Gbit/s systems with high PMD and prechirped CS-RZ modulation format

The authors present a 40 Gbit/s system model with standard forward error correction (FEC), high polarisation mode dispersion (PMD) and prechirped carrier-suppressed return-to-zero (CS-RZ) format. An approach to evaluation of the system performance is proposed for investigating the coding gain and transmission penalty of standard FEC. The numerical simulation results show that the interaction of the second-order PMD with nonlinearly induced chirp can improve the performance of FEC in some cases.

Performance evaluation of forward error correction in an ATM environment

The loss behavior of a cell multiplexer and the performance of forward error correction (FEC) for two homogeneous and one heterogeneous traffic scenarios are discussed. The loss behavior depends on the statistics of the source and on the traffic scenario. Simulation results indicate that the percentage of cells lost in a block is geometrically distributed. Using these results a mathematical model for the performance of FEC is developed, and the effectiveness of FEC for the three traffic scenarios is computed. It is shown that FEC is not effective for the two homogeneous scenarios. However, FEC reduces the loss rate for the video sources by several orders of magnitude for a heterogeneous scenario consisting of video and burst sources.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Performance evaluation of Forward Error Correction in ATM networks

If the packet loss rate in a network is higher than the loss rate requested by an application, the transport protocol must make up for the difference in loss rate. In high bandwidth delay-product networks the latency introduced by retransmission-based error recovery schemes may be too high for applications with latency constraints. In this case, Forward Error Correction (FEC) can be used. FEC allows recovery from loss without retransmission. The amount of loss recovered strongly depends on the loss behavior of the network. FEC works best if losses are dispersed in time. We use simulation to study the loss behavior of an output buffered multiplexer for three different traffic scenarios. Our results show how the loss behavior of the multiplexer is affected by the traffic mix and the statistics of the sources. The more bursty the sources, the higher the loss rate and the higher the probability that losses will occur in bursts. Based on simulation results, we develop a mathematical model for the performance of FEC and compute the effectiveness of FEC for the three traffic scenarios. FEC is not effective for the two homogeneous traffic scenarios. However, FEC reduces the loss rate for the video sources by several orders of magnitude for a heterogeneous traffic scenario consisting of video and burst sources.