Error Control Scheme Research Articles

Fountain code-based error control scheme for dimmable visible light communication systems

In this paper, a novel error control scheme using Fountain codes is proposed in on–off keying (OOK) based visible light communications (VLC) systems.By using Fountain codes, feedback information is needed to be sent back to the transmitter only when transmitted messages are successfully recovered. Therefore improved transmission efficiency, reduced protocol complexity and relative little wireless link-layer delay are gained. By employing scrambling techniques and complementing symbols, the least complemented symbols are needed to support arbitrary dimming target values, and the value of entropy of encoded message are increased.

Efficient Performance and Lower Complexity of Error Control Schemes for WPAN Bluetooth Networks

This paper presents a new technique of reduction retransmission time by decreasing the discarded packets and combating the complexity through error control techniques. The work is based on Bluetooth, one of the most common Wireless Personal Area Network. Its early versions employ an expurgated Hamming code for error correction. In this paper, a new packet format using different error correction coding scheme and new formats for the EDR Bluetooth packets are presented. A study for the Packet Error Probability of classic and Enhanced Data Rate (EDR) packets is also presented to indicate the performance. The simulation experiments are performed over Additive White Gaussian Noise (AWGN) and Rayleigh flat-fading channels. The experimental results reveal that the proposed coding scheme for EDR packets enhances the power efficiency of the Bluetooth system and reduce the losses of EDR packets.

Video Quality Analysis of Distributed Video Coding in Wireless Multimedia Sensor Networks

Multimedia communications in wireless sensor networks is a very challenging task. Video coding with high computational complexity and great contribution to the energy consumption of nodes and video transmission over erroneous wireless channel are the main reasons of these challenges. Distributed Video Coding has high potential for being deployed in these networks due to its unique features like as independent frame coding and low complexity encoding operations. The purpose of this study is to understand and evaluate the distributed video coding performance facing the transmission characteristics in wireless multimedia sensor networks. To this end, the comparative analysis of the coding in respect of main factors of video transmission (i.e., bit rate and error resiliency) in the Wireless Multimedia Sensor Networks (WMSN) has been done. We have used both the objective and subjective criteria for checking the video quality and applied the Gilbert-Elliot channel model for capturing the bit-level error in WMSN. Therefore, unlike previous works, our results are more realistic. In addition, based on this model we have investigated the impact of protection of frames by Reed-Solomon error control scheme. The results show that paying attention to coding parameters and protecting key frames, have a great impact on increasing the quality of the receiving video and will reduce the energy consumption and delays due to low number of requests from the feedback channel.

Error Control Based Energy Minimization for Cooperative Communication in WSN

As small-sized nodes are deployed in Wireless Sensor Networks (WSNs), efficient energy utilization becomes a fundamental challenge. Poor channel conditions lead to retransmissions resulting in unnecessary energy usage. To optimize energy consumption and improve network lifetime, error-control strategies are commonly required to manage channel impairments such as noise and fading. Cooperative commu nication is also considered a candidate solution to address the effects of channel fading. Therefore, the energy efficiency of cooperative schemes when applied with Automatic Repeat Request (ARQ), Hybrid-ARQ (HARQ), and Forward Error Correction (FEC) is investigated in this work. Moreover, expressions for energy efficiency of Direct Transmission, Single Relay Cooperation, and Multi Relay Cooperation are derived. Our work focuses on achieving energy-optimal communication in WSNs. Through simulations, it is observed that error-control strategies with a cooperative scheme can significantly enhance system performance in terms of energy optimization.

Diagnosis of singular points of structured DAEs using automatic differentiation

At a singular point of a DAE, the IVP fails to have a unique solution. Hence, numerical integration methods cannot provide reasonable results. Unfortunately, common error control strategies do not always detect these circumstances and arbitrary solutions may be given to the user without warnings of any kind. Automatic (or Algorithmic) Differentiation (AD) opens new possibilities to realize an analysis of DAEs and to monitor assumptions required for the existence and uniqueness of IVPs. We show how the diagnosis of singular points can be performed for structured quasi-linear DAEs up to index 2. Our approach uses the projector based analysis for DAEs employing AD. The resulting method is illustrated by several examples, with particular emphasis on simple electrical circuits containing controlled sources.

Cross-layer analysis via Markov models of incremental redundancy hybrid ARQ over underwater acoustic channels

Underwater acoustic networks make it possible to wirelessly convey information, e.g., coming from measurements and sensing applications from under water to the surface. However, underwater communications are characterized by long delays, small available bandwidths and high error rates. These aspects may significantly affect the design of a reliable data-link layer for such systems. In this paper, we assess the performance of hybrid automatic repeat request error control schemes and we evaluate their application to improve the reliability of time-varying underwater acoustic links. We employ a parametric Markov model, which has been trained over channel traces collected during at-sea experiments. The results, based on both experimental data and analysis, suggest that parametric probabilistic representations, such as the considered Markov model, are good candidates for describing the correlated underwater acoustic channel dynamics, and may be employed to achieve a realistic evaluation of the data-link layer performance for underwater acoustic scenarios. Analytical and simulation results confirm that incremental redundancy improves the throughput of underwater acoustic links, even when real channel conditions, such as those encountered in the considered experiments, have wide dynamics over time. Finally, this kind of evaluations, beyond the data-link design, can also be employed at the network level for routing and network deployment considerations.

Predictable and reliable ECG monitoring over IEEE 802.11 WLANs within a hospital.

Telecardiology provides mobility for patients who require constant electrocardiogram (ECG) monitoring. However, its safety is dependent on the predictability and robustness of data delivery, which must overcome errors in the wireless channel through which the ECG data are transmitted. We report here a framework that can be used to gauge the applicability of IEEE 802.11 wireless local area network (WLAN) technology to ECG monitoring systems in terms of delay constraints and transmission reliability. For this purpose, a medical-grade WLAN architecture achieved predictable delay through the combination of a medium access control mechanism based on the point coordination function provided by IEEE 802.11 and an error control scheme based on Reed-Solomon coding and block interleaving. The size of the jitter buffer needed was determined by this architecture to avoid service dropout caused by buffer underrun, through analysis of variations in transmission delay. Finally, we assessed this architecture in terms of service latency and reliability by modeling the transmission of uncompressed two-lead electrocardiogram data from the MIT-BIH Arrhythmia Database and highlight the applicability of this wireless technology to telecardiology.

Evaluation of the Resequencing Delay for Selective Repeat ARQ in TDD-Based Wireless Communication Systems

This paper deals with the modeling and analysis of the resequencing delay in time-division duplexing communication systems that adopt the Selective Repeat Automatic Repeat-reQuest error control strategy. Under the assumption that packet misordering at the receiving end is induced by channel errors, this paper proposes an analytical approach based on the absorbing Markov chain theory to accurately predict the impact of the resequencing delay on the quality of the provided services. Numerical results, which are derived by means of computer simulations, are also given to validate the proposed analytical model.

Modified Function Projective Synchronization Using Feedback Error Control

Some new simple control methods of modified function projective synchronization in two chaotic systems are investigated in this paper. Based on Lyapunov method, a general feedback error control law is proposed, which contains only feedback error term and easy to implement in practice. Moreover, an adaptive feedback error control scheme is proposed, in which the feedback gain can be automatically adapted to suitable constant. Numerical example is provided to show the effectiveness of proposed method.

Energy Efficient and High Speed Error Control Scheme for Real Time Wireless Sensor Networks

Reliability and energy consumption are two of the main constraints in wireless sensor networks (WSNs). In this paper, a novel energy efficient and high speed error control scheme is introduced that is based on the Redundant Residue Number System (RRNS) allowing real-time application of WSNs. The proposed approach employs a new 3-moduli set [Formula: see text] and an efficient reverse converter which relies on the Mixed Radix Conversion (MRC) algorithm and achieves significant improvements both in terms of conversion delay and hardware design. In order to obtain error controllability, two-redundant-moduli set [Formula: see text] is also added to the main 3-moduli set. The theoretical results backed by simulation tests confirm that the solution put forward in this paper outperforms popular error control methods for WSNs in terms of error controllability, energy efficiency, and reduction of end-to-end delay.

3G 네트워크에서 MPEG-4 스케일러블 비디오의 실시간 방송을 위한 실행시간 예측 기반 MAC계층 오류제어

본 논문에서는 CDMA2000 1xEV-DO의 매체 접근 제어 계층에서 현재 순방향 오류 정정 방법으로 사용되고 있는 리드-솔로몬 복호화 과정의 수행 시간을 다양한 채널 조건에서 분석하였다. 그 결과, 트래픽 채널의 패킷 손실률이 특정 수준 이상으로 높을 경우 리드-솔로몬 복호기의 수행 시간이 길어져 MPEG-4 비디오의 시간 제약을 보장할 수없음을 확인하였다. 이러한 문제를해결하기 위해서본 연구에서는3가지의 기법을제시하였다. 첫째, 정적기법은 패킷 손실률이 특정 임계값 이상일 경우 리드-솔로몬 복호를 생략함으로써 MPEG-4의 시간 제약을 맞춘다. 두 번째 동적 기법은 패킷 손실률이 높더라도 모든 리드-솔로몬 복호를 생략하지는 않고MPEG-4의 시간 제약을 맞출 수 있는 범위 안에서 최대한으로 복구를 수행한다. 마지막 기법인 비디오 인지 동적 기법은 동적 기법과 비슷하지만 비디오 복호에 대한 기여도에 따른 우선 순위 기반으로 복구를 함으로써 비디오의 품질을 더욱 향상시키는 것이다. 우리는 본 논문에서 제안한 기법들을 활용하는 것이 실시간 비디오방송의 서비스 품질을 크게 향상시킬 수 있음을 다양한 실험을 통해 입증하였다. We analyze the execution time of Reed-Solomon coding, which is the MAC-layer forward error correction scheme used in CDMA2000 1xEV-DO broadcast services, under different air channel conditions. The results show that the time constraints of MPEG-4 cannot be guaranteed by Reed-Solomon decoding when the packet loss rate (PLR) is high, due to its long computation time on current hardware. To alleviate this problem, we propose three error control schemes. Our static scheme bypasses Reed-Solomon decoding at the mobile node to satisfy the MPEG-4 time constraint when the PLR exceeds a given boundary. Second, dynamic scheme corrects errors in a best-effort manner within the time constraint, instead of giving up altogether when the PLR is high; this achieves a further quality improvement. The third, video-aware dynamic scheme fixes errors in a similar way to the dynamic scheme, but in a priority-driven manner which makes the video appear smoother. Extensive simulation results show the effectiveness of our schemes compared to the original FEC scheme.

Low-weight error-prevention codes for electromagnetic nanonetworks in the Terahertz Band

In this paper, a novel error control strategy for electromagnetic nanonetworks, based on the utilization of low-weight channel codes and aimed at the prevention of channel errors, is proposed. In particular, it is first analytically shown that both the molecular absorption noise and the multi-user interference in nanonetworks can be mitigated by reducing the channel code weight, which results into a lower channel error probability. Then, the relation between the channel code weight and the code word length is analyzed for the case of utilizing constant weight codes. Finally, the performance of the proposed strategy is analytically and numerically investigated in terms of the achievable information rate after coding and the Codeword Error Rate (CER). Two different receiver architectures are considered, namely, an ideal soft-receiver and a hard receiver. An accurate Terahertz Band channel model and novel stochastic models for the molecular absorption noise and the multi-user interference, validated with COMSOL, are utilized. The results show that low-weight channel codes can be used to reduce the CER without compromising the achievable information rate or even increasing it, especially for the hard-receiver architecture. Moreover, it is shown that there is an optimal code weight, for which the information rate is maximized.

Performance of multi-hop CDMA wireless sensor networks with correlated interferers using different retransmission strategies and error control schemes

Energy efficient reliable communication is a major challenge for resource constrained wireless sensor networks (WSNs). This paper evaluates the end-to-end performance of a CDMA-based static multi-hop WSN with layered architecture in shadowed environment. Two popular information delivery mechanisms with error control are considered. End-to-end error correction and control using HARQ-type I with Bose Chaudhuri Hocquenghem (BCH) coding is considered, where BCH decoding is used only at the sink which has enough power to run the complex decoding algorithm. Performance of the network system using hop by hop ARQ mechanism at every intermediate node is also compared with that of end-to-end error control scheme. An interference model for multi-hop is presented considering correlation amongst shadow faded interferers. Energy requirement, and delay for successful delivery of a data packet from a source to sink is evaluated for each packet transmission scheme considering a suitable energy model and compared under several conditions of node density, packet length, number of hops between source and sink. Further energy efficiency for each scheme is evaluated and compared. Analytical results are supported by simulation.

Multiplexing and Error Control Scheme for Body Area Network Employing IEEE 802.15.6

This paper proposes and investigates a multiplexing and error control scheme for Body Area Network (BAN). In February 2012, an international standard of WBAN, IEEE802.15.6, was published and it supports error control schemes. This standard also defines seven different QoS modes however, how to utilize them is not clearly specified. In this paper, an optimization method of the QoS is proposed. In order to utilize the QoS parameters, a multiplexing scheme is introduced. Then, the Hybrid ARQ in IEEE 802.15.6 is modified to employ decomposable codes and Weldon's ARQ protocol for more associations with channel conditions and required QoS. The proposed scheme has higher flexibility for optimizing the QoS parameters according to the required QoS.

On modelling network coded ARQ-based channels

Network coding (NC) offers throughput improvements by algebraically combining multiple input packet streams which address one output port at an intermediate node. We present a practical implementation of NC with error control, namely stop-and-wait automatic repeat request (SW ARQ). We apply a modified NC scheme at an intermediate SW ARQ-based link to reduce ARQ control signals and then extend this to NC in a butterfly multicast network which adopts the selective repeat (SR) ARQ protocol as its error control scheme. We validate our throughput analysis using a relatively recent discrete-event simulator, SimEvents®. The results show a throughput advantage of at least 50%, particularly in the presence of high error rates. In the multicast SR ARQ network, NC-SR ARQ effectively doubles the throughput compared with the traditional scheme and increases the protocol’s ability to deal with propagation times that are long in comparison with the packet inter-arrival time.

Performance Evaluation of Some Dynamic ARQ Schemes for Multichannel Communication System

In this paper, we propose two dynamic error control schemes and apply them to the multichannel data communication system. The proposed schemes are based on the basic Stop-and-Wait ARQ and Selective Repeat ARQ protocols, The former and latter are used for the error controls in a round-trip time and among the multiple channels in a slot, respectively. The state of each channel is assumed as Markov chain with two states. The operations of the proposed schemes are described and their performances are evaluated through computer simulation. The numerical results show that the performances of the proposed schemes are improved remarkably comparing with the traditional scheme.

Smart error-control strategy for low-power communication in wireless networked control system

We consider a Wireless Networked Control System (WNCS) in an indoor environment and discuss the impact of wireless channel characteristics on the stability and performance of wireless feedback cont...

Error Correcting Mechanisms during Antisaccades: Contribution of Online Control during Primary Saccades and Offline Control via Secondary Saccades

Errors in eye movements can be corrected during the ongoing saccade through in-flight modifications (i.e., online control), or by programming a secondary eye movement (i.e., offline control). In a reflexive saccade task, the oculomotor system can use extraretinal information (i.e., efference copy) online to correct errors in the primary saccade, and offline retinal information to generate a secondary corrective saccade. The purpose of this study was to examine the error correction mechanisms in the antisaccade task. The roles of extraretinal and retinal feedback in maintaining eye movement accuracy were investigated by presenting visual feedback at the spatial goal of the antisaccade. We found that online control for antisaccade is not affected by the presence of visual feedback; that is whether visual feedback is present or not, the duration of the deceleration interval was extended and significantly correlated with reduced antisaccade endpoint error. We postulate that the extended duration of deceleration is a feature of online control during volitional saccades to improve their endpoint accuracy. We found that secondary saccades were generated more frequently in the antisaccade task compared to the reflexive saccade task. Furthermore, we found evidence for a greater contribution from extraretinal sources of feedback in programming the secondary “corrective” saccades in the antisaccade task. Nonetheless, secondary saccades were more corrective for the remaining antisaccade amplitude error in the presence of visual feedback of the target. Taken together, our results reveal a distinctive online error control strategy through an extension of the deceleration interval in the antisaccade task. Target feedback does not improve online control, rather it improves the accuracy of secondary saccades in the antisaccade task.

Analyzing and improving the energy efficiency of IEEE 802.15.4 wireless sensor networks using retransmissions and custom coding

This paper analyzes the performance of error control strategies in IEEE 802.15.4 wireless sensor networks. ARQ schemes of the IEEE 802.15.4 are used and also we propose custom coding using BCH codes. The performance is analyzed through simulation using the energy efficiency parameter. Performance results are obtained for multi-hop networks with different channel conditions and packet sizes. The results have shown that the ARQ scheme and BCH codes are energy efficient for networks with high number of hops and low values of signal-to-noise ratio.

Design and QoS of a Wireless System for Real-Time Remote Electrocardiography

Quality of service (QoS) and, in particular, reliability and a bounded low latency are essential attributes of safety-critical wireless systems for medical applications. However, wireless links are typically prone to bursts of errors, with characteristics which vary over time.We propose a wireless system suitable for real-time remote patient monitoring in which the necessary reliability and guaranteed latency are both achieved by an efficient error control scheme. We have paired an example remote electrocardiography application to this wireless system. We also developed a tool chain that uses a formal description of the proposed wireless medical system architecture in the architecture analysis and design language to assess various combinations of system parameters: we can determine the QoS in terms of packet-delivery ratio and the service latency, and also the size of jitter buffer required for seamless ECG monitoring. A realistic assessment, based on data from the MIT-BIT arrhythmia database, shows that the proposed wireless system can achieve an appropriate level of QoS for real-time ECG monitoring if link-level error control is correctly implemented. Additionally, we present guidelines for the design of energy-efficient link-level error control, derived from energy data, obtained from simulations.