Adaptive Error Control Scheme Research Articles

InTraSim: Incremental Transient Simulation of Power Grids

Effective transient power grid simulators are needed during design processes because a designed power grid needs to be numerously analyzed. This paper builds an efficient and reliable incremental power grid transient simulator, which we name it InTraSim, by integrating macro modeling techniques, sparse recovery mechanisms, an innovated pseudo-node value estimation method, and an initiated adaptive error control scheme. InTraSim is able to deal with not only element-value alterations of designs but also topology modifications of designs.

Adaptive Multibit Crosstalk-Aware Error Control Coding Scheme for On-Chip Communication

The presence of different noise sources and continuous increase in crosstalk in the deep submicrometer technology raised concerns for on-chip communication reliability, leading to the incorporation of crosstalk avoidance techniques in error control coding schemes. This brief proposes joint crosstalk avoidance with adaptive error control scheme to reduce the power consumption by providing appropriate communication resiliency based on runtime noise level. By switching between shielding and duplication as the crosstalk avoidance technique and between hybrid automatic repeat request and forward error correction as the error control policies, three modes of error resiliencies are provided. The results show that, in reduced mode, the scheme achieves up to 25.3% power savings at 3-mm wire length as compared to the original nonadaptive scheme at the cost of only 3.4% power overhead in high protection mode.

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.

An Adaptive Error Control Scheme in Wireless Sensor Networks Based on LQI

Aiming at the character of high bit error rate and energy constraints on WSN, this paper proposed an adaptive error control scheme based on link quality indicator(LQI). The PHY specification of IEEE802.15.4 provided accurate measurement of channel quality for WSN, according to the quantitative relationship between LQI and bit error rate, this paper divided the channel quality into eight levels non-uniformly, furthermore, eight different BCH code were chosen correspondingly. The motes choose optimal BCH code as its error correction scheme in real time. Experimental results show the scheme is high in energy efficiency, meanwhile, drops the error probability effectively.

Dual-Layer Adaptive Error Control for Network-on-Chip Links

In this work, we present a new error control method to improve the energy efficiency and reliability of network-on-chip (NoC) links. The proposed method combines the error control coding (ECC) capabilities of the NoC's datalink and network layers to dynamically adjust the error control strength in variable noise conditions. Network-layer ECC is used in low noise conditions and error control strength is enhanced by adding datalink-layer ECC in high noise regions. To switch between the two ECC modes at runtime without interrupting normal operation, we propose a dual-layer cooperative error control protocol and its hardware-efficient implementation using the concept of product codes. Theoretical analyses of residual error rate and performance show the proposed method outperforms previous single-layer fixed and adaptive error control schemes. Compared to previous solutions, the proposed method reduces residual packet error rate by up to four orders of magnitude, achieves up to 72% energy reduction and improves average latency by up to 64%. The energy and latency reduction benefits are maintained as the routing path length and packet size increase, at the cost of a moderate increase in area overhead.

Adaptive hybrid ARQ for mode switching receiver in wireless cellular networks

In this paper, an adaptive error control (AEC) scheme is developed for a switched–and–stay combiner (SSC) of a dual–branch selection diversity receiver. It relies on a type–I hybrid combination of selective repeat SR–ARQ and BCH coding at the data link layer. The model is then called adaptive error control based switched–and–stay combiner (AEC–SSC) in mobile cellular networks. The aim is to provide maximal achievable throughput when AEC–SSC is employed in Rayleigh flat–fading channel. The results show that significant redundancy coding has a reasonable effect on the overall throughput performance. In contrary, the adaptive channel coding influences significantly on the lower range of operating channel SNR in hybrid ARQ compared to non–adaptive ARQ scheme.

Low-complexity adaptive error-control schemes for real-time scalable video transmission over WLANs

In this paper, an adaptive video packet transmission mechanism under WLAN is proposed. In terms of the following characteristics: optimal packet length, layering and scalability of MPEG-4 FGS and Unequal Error Protection (UEP), the low calculation complication is applicable to real-time environments. The findings show that the optimal packet length can be obtained through mathematical analysis according to the current wireless network transmission status and the header overhead. Compared to several distinct scalable video transmission schemes, the simulation results reveal that our transmission scheme is capable of reacting to the varying channel condition with less and smoother quality degradation.

Network lifetime optimization for wireless video sensor networks with network coding/ARQ hybrid adaptive error-control scheme

This paper addresses the performance optimization of network lifetime and resource allocation for wireless video sensor networks. Network flow control and video encoding bit rate are jointly optimized, aiming to maximize the network lifetime at a given power budget and video quality requirement. We develop a generalized power consumption model for video sensors, in which video encoding, data communication and error-control behavior are completely considered. To combat packet loss over wireless channels, a hybrid error-control scheme integrating network coding and ARQ protocol is introduced. It adaptively adjusts the number of redundant coded packets according to ARQ feedbacks with a fixed code structure and decoding algorithm. Through the Lagrange dual and subgradient approach, a fully decentralized algorithm is proposed to solve the target convex problem. Finally, simulation results validate the convergence and performance of the proposed algorithm in a large-scale random topology as well as in a small static network.

An energy efficiency model for adaptive and custom error control schemes in Bluetooth sensor networks

This paper analyzes the effect of custom error control schemes on the energy efficiency in Bluetooth sensor networks. An analytical model is presented to evaluate the energy efficiency metric, which considers in just one parameter the energy and reliability constraints of wireless sensor networks. New packet types are introduced using some error control strategies in the AUX1 packet, where custom coding can be implemented. Two adaptive techniques are proposed that change the error control strategy based on the number of hops traversed by a packet through the network. A packet selection strategy based on channel state is proposed for sensor networks with different channel conditions. Performance results are obtained through analysis and simulation in Nakagami- m fading channels for networks with different number of hops and channel conditions.

Robust video streaming over wireless LANs using multiple description transcoding and prioritized retransmission

Video transport over wireless Local Area Networks (LANs) usually suffers from signal fading, noise interference, and network congestion, leading to time-varying packet loss rate and fluctuating effective bandwidth. We propose in this paper an adaptive error control scheme to adaptively insert error-resilience features into a compressed video in the media gateway which serves roaming clients. Our scheme divides the error control operation into the single description (SD) and multiple-description (MD) modes according to channel condition estimation. In the SD mode, a content-based prioritized retransmission method is proposed to mitigate the error propagation due to packet loss in video transport over wireless LANs. The proposed prioritized retransmission scheme determines the retransmission schedule of a lost packet according to the packet’s loss impact that is obtained in a front-end encoding process. In the MD mode, we propose a channel-aware MD transcoding method to take advantage of MD coding and path diversity so as to further mitigate the error propagation due to packet loss caused by transient channel switching while roaming in wireless LANs. Experimental results show that the proposed scheme effectively mitigates the error propagation due to packet loss, while maintaining low extra computational complexity and low overhead cost. The proposed method is suitable for realtime streaming of prestored videos.

Adaptive Low-Complexity Erasure-Correcting Code-Based Protocols for QoS-Driven Mobile Multicast Services Over Wireless Networks

We propose an adaptive hybrid automatic repeat request-forward error correction (ARQ-FEC) erasure-correcting scheme for quality of service (QoS)-driven mobile multicast services over wireless networks. The main features of our proposed scheme include (i) the low complexity achieved by the graph code; (ii) dynamic adaptation to the variations of packet-loss level and QoS requirements. To increase error-control efficiency and support diverse QoS requirements, we develop a two-dimensional (2-D) adaptive error-control scheme that dynamically adjusts not only the error-control redundancy, but also the code mapping structures. By deriving and identifying the closed-form nonlinear analytical expression between the optimal check-node degree and the packet-loss level, we propose the nonuniformed adaptive coding structures to achieve high error-control efficiency. Applying the Markov chain model, we obtain closed-form expressions that derive the error-control redundancy as a function of packet-loss level and the optimal check-node degree in each adaptation step. The convergency of error-control redundancy adaptation is dynamically controlled by different QoS requirements such that a high error-control efficiency can be achieved. Using the proposed 2-D adaptive error control, we design an efficient hybrid ARQ-FEC protocol for mobile multicast services with diverse reliability QoS requirements. The proposed scheme keeps the feedback overhead low by consolidating only the numbers rather than the sequence numbers of the lost packets, which are fed back by multicast receivers. Also conducted is a set of numerical and simulation evaluations that analyze and compare our proposed adaptive scheme with those using nonadaptive graph codes, Reed-Solomon erasure codes (RSE), and the pure ARQ-based approach. The simulation results show that our proposed scheme can efficiently support QoS-driven mobile multicast services and achieve high error-control efficiency while imposing low error-control complexity and overhead for mobile multicast networks

이동 컴퓨팅 환경에서 멀티미디어 서비스 지원을 위한 적응적 에러 제어 기법

Mobile computing has such characteristics as portability, wireless network, mobility, etc. These characteristics cause various problems to mobile terminals like frequent disconnection, high error rate, and varying network status. These problems motivate us to develop an adaptive error control mechanism for supporting multimedia service in mobile computing environment. In this paper, we propose the Adaptive Error Control(AEC) scheme using client`s buffer size and current error rate. After categorizing the status into four groups according to client`s buffer size and current error rate, this scheme applies an appropriate error control scheme to each status. In this scheme, thresholds of buffer size and error rate are determined by the data transmission time, play rate and average VOP size, and by the probability of error for a sequence of packets. The performance of proposed scheme is evaluated by flaying MPEG-4 files on an experimental client/server environment, respectively. The results show that error correcting rate is similar to other schemes while the time for correcting error reduce a little. In addition, the size of data for correcting error is decreased by 23% compared with FEC and Hybrid FEC, respectively. Theses results demonstrate that the proposed scheme is more suitable in mobile computing environment with small bandwidth and varying environment than existing schemes.

QoS‐based adaptive error control for wireless networks

AbstractWireless channels are highly affected by unpredictable factors such as cochannel interference, adjacent channel interference, propagation path loss, shadowing, and multipath fading. The unreliability of media seriously degrades the transmission quality. Automatic Repeat reQuest (ARQ) and Forward Error Correction (FEC) schemes are frequently used in wireless environments to reduce the high bit error rate of the channel. In this paper, we propose an adaptive error‐control scheme for wireless networks on the basis of dynamic variation of error‐control strategy as a function of the channel bit error rate, desired QoS, and number of receivers. Reed–Solomon codes are used throughout this study because of their appropriate characteristics in terms of powerful coding and implementation simplicity. Simulation results show that our adaptive error‐control protocol decreases the waste of bandwidth due to retransmissions or extra coding overheads while satisfying the QoS requirements of the receivers. Copyright © 2002 John Wiley & Sons, Ltd.

A class of adaptive hybrid ARQ schemes for wireless links

Wireless links are known to suffer location-dependent, time-varying, and bursty errors. This paper considers a class of adaptive error-control schemes in the data link layer for reliable communication over wireless links in which the error-control code and the frame length are chosen adaptively, based on the estimated channel state/condition. Three error-control schemes are considered according to: (1) the number of Reed Solomon code segments a packet is divided into and (2) the way a lost packet is retransmitted. Through throughput performance and computation complexity analyses, these three schemes are compared, and then one of them is claimed to be the most attractive in terms of computation complexity and practicality even though its throughput performance is not the best. The simulation results also verify that this scheme works well over a time-varying fading channel. Error control for the medium access control (MAC) header and its effect on the performance of each error-control scheme are also considered since, without proper error protection for the header, it would be futile to exercise error control on the user data.

Group 3 error-free facsimile terminal for analog cellular networks

A Group 3 error-free facsimile terminal for use in an analog cellular network has been developed. This facsimile terminal is provided with the International Telecommunication Union (ITU-T, formerly CCITT) T.30 recommendation protocol and an adaptive error control scheme (AECS) for Group 3 communication and error-free communication. The AECS monitors the channel conditions and selects the optimum error correction code. The ITU-T V.27ter is used as the modulation method and the transmission rate is 4800 bps. This system is compatible with the modified Huffman (MH), modified READ (MR), and modified modified READ (MMR) image data compression codes. The average communication time of this facsimile terminal is 40 s per page while moving through the analog cellular network.

A concatenated two-stage adaptive (CTSA) error control scheme for data transmission in time-varying channels

A concatenated two-stage adaptive error control scheme with automatic repeat request (ARQ) has been developed which is especially suitable for severely fading channels and for a very broad range of signal-to-noise ratios. This new scheme uses two stages of adaptive coding: the inner code is a rate compatible binary block code which due to its short blocklength can be maximum likelihood decoded taking into account soft-decisions and channel state information. For retransmissions code combining can be used. The outer code is a Reed-Solomon code which is maximum-distance separable and can correct error bursts as well as erasures indicated by the inner decoder. No interleaving is necessary and no critical optimization of system parameters is required to adapt to different channels and signal-to-noise ratios. In the paper, the scheme is described in detail and its throughput efficiency is analyzed. Also, simulation results for the throughput in the Gaussian and in the Rayleigh channel are presented. It is shown that the proposed error control scheme offers excellent throughput performance. Compared to other schemes, the new scheme maintains its efficiency over a very broad range of signal-to-noise ratios.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Superconvergent boundary stress extraction and some experiments with adaptive pointwise error control

AbstractIn Reference 1, a class of extraction formulations were developed to recover solution quantities with superconvergent accuracy. As a continuation, this paper documents some new developments in the boundary stress extraction method to expand its applications to boundary locations that are not traction‐free. Furthermore, the convergence characteristics of the extracted pointwise stress are investigated in an h‐adaptive process using different adaptive error control schemes. Observations from those numerical experiments provide some initial insight toward the development of an adaptive approach that can obtain prescribed pointwise solution accuracy with optimal computation efficiency.

Protocol configuration and verification of an adaptive error control scheme over analog cellular networks

A high-speed and error-free voiceband data communication method using a hybrid automatic repeat request (ARQ) protocol over an analog cellular system is described. The present method adopts an adaptive error control scheme. This error control scheme automatically selects the optimal error correction code according to circuit bit error rate (BER), so as to match it to the frequently changing mobile radio propagation path conditions. This method adopts multiframe rejection as a retransmission scheme for a high throughput efficiency on the burst error circuit. Actual field evaluation was made by mounting this protocol on a CCITT V.22 bis modem with a data transmission speed of 2400 b/s and a modulation method using 16 carrier states over the Advanced Mobile Phone Service (AMPS) in Atlanta, GA, verifying that data communications can be achieved with an average throughput efficiency of 70% over a radio channel having a BER up to 10/sup -2/.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Simulation of burst error models and an adaptive error control scheme for high speed data transmission over analog cellular systems

To realize high-speed data communication in a cellular system, the characteristics of mobile radio propagation paths (MRPP) and a robust error control scheme for poor circuit quality are studied. MRPP are analyzed by computer simulation, and an analysis method is described that uses a Markov model for burst errors generated by the simulation. By simulating the locus of moving vehicles, the relationship between the carrier-to-noise ratio (CNR), the fading frequency of a moving vehicle, and the three-states Markov model is obtained. An adaptive error control scheme (AECS) is developed as an effective high-speed data communication scheme in an analog cellular system. The effectiveness of the AECS is analyzed by simulating its application in a subcarrier transmission system with a 4800 b/s data transmission rate, using the three-states Markov model. The analysis method is verified and the characteristics of the AECS are evaluated using field data.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Composition of robust error control scheme using adaptive coding and its effect on data communication

AbstractThis paper describes a robust error control scheme used for propagation paths especially involving a long time‐frame burst error as in mobile radio communication and its effect on actual data communication channels. This is an adaptive error control scheme based on forward error correction code and composed adaptively of plural coding modes.Here, the BCH code is used as a block code, the diffused code is used as a convolutional code, and 3–5 majority logic is used as a majority voting code. The optimum coding mode is selected automatically according to the status of data transmission channels composed of a radio transmission span and telephone cable transmission lines. Cyclic code is used as an error detection method to evaluate channel status.Under practical transmission circumstances, extremely high throughput efficiency of more than 70 percent is realized for 4800 bit/s data for transmission over the cellular network in Britain. This scheme has been presented at CCITT SG XVII as a standard scheme candidate.