Residual Error Rate Research Articles

Controle de Erros em Redes ATM sem Fio

ATM networks have been designed considering the use of optical links in the physical layer, which present low bit error rate. The main problem in implementing wireless ATM networks is the high and variable bit error rate in the radio link. To overcome this problem, it is necessary to use an additional error control mechanism in the wireless link. The traditional techniques for error control are ARQ (Automatic Repeat Request) and FEC (Forward Error Correction). Using FEC or ARQ techniques in the wireless link decreases the residual bit error rate, increases the delay in transmitting a packet and decreases the throughput, due to overhead of the error control mechanisms. This paper presents a comparison of the performances of ARQ and FEC techniques in wireless ATM networks considering adaptive and non-adaptive systems and real-time and nonreal time applications. The criteria to compare the performances are: the delay to transmit a PDU (Protocol Data Unit), for real-time applications, and, for non-realtime applications, the throughput and the average and maximum cell transference delays.

On the importance of error resilience in visual communications over noisy channels

This paper presents the importance of error resilience tools in visual communications. Error resilience tools provide a mechanism enabling transmission of visual information over channels with residual random bit errors in the received bit stream. The benefits of using error resilience tools are proven by devising the analytic relationship between the time delay in a transparent channel using automatic repeat request (ARQ) and the equivalent residual bit error rate in a nontransparent channel. The error resilience tools make it possible to achieve an acceptable visual quality even in the presence of these residual errors. Our work is related and compared to the standardization work of the next-generation still image compression system JPEG2000. The results show that partial and complete substitution of the quantization and symbol encoding in visual compression systems by robust error resilience tools provides a significant increase in robustness. Three error resilience tools are discussed: (1) substitution of the quantization and symbol encoding by a fixed length coding scheme, (2) substitution by a mixed fixed length coding and variable length coding scheme, and (3) substitution of the variable length coding by reversible variable length coding.

Some results on error control for burst-error channels under delay constraints

This paper considers the problem of designing an error control scheme under delay constraints and presents some new results. In particular, the performance of some error-correction block codes and of the Go-Back-N retransmission scheme is investigated, when a packetized stream of bits is to be transmitted across a burst-error channel. The presence of a delay constraint causes degraded the error-correction performance (due to nonideal interleaving) and block dropping in Go-Back-N (due to retransmission delay). An approximate characterization of the residual bit error rate at the output of the error-control scheme is presented, and the effect of the channel burstiness, type of codes used, and channel data rate on the tradeoffs between the residual bit error rate and delay, and between the delay and achievable information rate is examined.

Typical error pattern recovery of the Hopfield memory under error-tolerant conditions

We lower-bound the error-correcting capabilities of the Hopfield (1982) network under error-tolerant conditions, given some distorted version of a fundamental memory with a random (typical) error pattern. Our main result is that for any sufficiently small /spl alpha/, and for any /spl rho/<1/2, a Hopfield memory with n neurons can store /spl alpha/n fundamental memories, such that the following is satisfied in probability: a distorted fundamental memory with /spl rho/n errors, located at random positions may be corrected up to a residual error rate of exp{-1/2/spl alpha/}.

Determination of best shortened linear codes

The quality of a block code is determined by its capability to protect data against undetectable errors and by the number of check bits that are required for that purpose. For a given number of check bits there are codes with optimum bit error detecting capability in shortened block lengths. These codes are determined and tabulated. The residual error characteristics of some of the tabulated codes are compared with those specified in ISO/CCITT or IEC standard data transmission protocols. For block lengths and bit error rates that are typical in process control applications, the residual error rate of the determined codes is more than six orders of magnitude smaller than that of codes specified by widely used standard transmission protocols.

Class of DC-freeerror correcting codesbased on convolutional codes

A new class of DC-free error correcting codes based on convolutional codes is proposed and its performance analysed. The proposed codes can be encoded and decoded using conventional convolutional encoders and decoders with slight modifications. The residual bit error rate and power spectral density of the proposed code are obtained and presented.

New very high rate punctured convolutional codes

New very high rate punctured convolutional codes suitable for Viterbi decoding are presented. These codes extend recent results on high rate convolutional codes by employing an efficient computer search technique and are optimum in that they minimise the residual bit error rate over all puncturing patterns given a particular basis code. Tables of new codes of rate (n–1)/n are given for n = 9, 10, 11 and 12.

INTEGRATING GEOGRAPHIC INFORMATION SYSTEMS AND MODFLOW FOR GROUND WATER RESOURCE ASSESSMENTS1

ABSTRACT: The Floridan Aquifer is the primary source of water in the coastal area of Santa Rosa County, Florida. In order to optimize well field design and analyze aquifer stress problems, the USGS MODFLOW code (McDonald and Harbaugh, 1988) is applied to develop a numerical computer model of the aquifer. The Geographical Information System (GIS) is the primary tool used in the development of the model grid, performance of the modeling procedure, and model analysis. The GIS is used in generating multiple grids in which to simulate both regional scale and local scale flow. The grid topology is recorded in geographic coordinates which facilitates geo‐referencing and orientation of the grid to base maps and data coyerages. The GIS allows data transfer from various coverages to the nodes of the block centered grid where hydrogeologic information is stored as attributes to the grid coverage. From this grid coverage, pertinent information is queried within the GIS environment and used to generate the input files for the MODFLOW simulation. After MODFLOW execution, simulated heads and drawdown are imported into the grid coverage where residual error and recharge rates can be calculated. Contoured surfaces are then created for selected data sets including simulated heads, drawdown, residual error, and recharge rates. Model calibration is conducted utilizing the GIS to generate and process data sets associated with model simulations.

An ARQ/FEC coding scheme for land mobile communication

AbstractThis paper describes the development of a laboratory test unit that implements a new Type I/II ARQ scheme for use on a land mobile forward satellite link. Investigation of channel characteristics showed that it was possible to use convolutional coding to combat random errors, but it was also necessary to employ an ARQ scheme in order to overcome fades due to signal blockage.The hardware development used commercial 68000‐based VME cards as well as special‐purpose cards to perform the functions of Viterbi decoding and packet synchronization.Results are presented for the hardware operating with Gaussian noise as time limitations excluded the use of satellite fading simulation. In order to ensure a high degree of data integrity error detection was applied to the data packets such that a residual error rate of less than 10−11 should result. This was not able to be verified due to the limited time. However, long term tests did indicate that an error rate less than 10−8 was achieved.

Practical error probability estimation for digital radio systems in the presence of interference and noise of finite crest factor, and prediction of residual error rate

Practical error probability estimation for digital radio systems in the presence of interference and noise of finite crest factor, and prediction of residual error rate

Utilization of error correcting codes for data transmission simulations

We present a software program simulating data transmission through a noisy channel. This program makes it possible to simulate simplex or full duplex transmissions of digitalized data, of any type. Through a modelization of the error rate and of the kinds of errors we can simulate transmissions, from submarine ones (error rate about 10 -2) to transmissions via satellites (error rate about 10 -5 to 10 -8). This software operates from one initial file to be transmitted, and from user-entered parameters of simulation. The final results are of two kinds: two files, and several numerical results. The two files are: The initial one transmitted without data protection, and the initial one transmitted with data protection by error correcting codes. The numerical results are: The binary experimental error rate, the binary residual error rate, and the transmission efficiency.

8 GHz, 10 W solid-state power amplifier for microwave digital radio

An 8 GHz, 10 W GaAs FET prototype power amplifier has been developed to replace the TWT in the Northern Telecom&apos;s digital microwave radio system. For a single bit stream of 91.04 Mbit/s, the residual bit error rate at 40 dBm output level was 1.0×10−32 compared with 1.0×10−23 for TWT; the AM/AM conversion ratio was 0.375 dB/dB and AM/PM was 0.84°/dB. The total mean time between failure of the amplifier was 350 000 h.

Important Performance Criteria for Distribution Line Carrier System

Published performance of distribution line carrier communications confuse or mislead through their lack of standard performance metrics. This paper presents metrics of communication system performance which can be used to evaluate distribution line carrier systems when used over power distribution lines for automatic distribution functions such as load control, feeder automation, meter reading, and load survey. The emphasis in this paper is on fundamental quantities like throughput and residual error rate which are often used to measure the effectiveness of other data transmission systems and networks. A sample, calculation of system requirements is included.

Important Performance Criteria for Distribution Line Carrier System

Published performance of distribution line carrier communications confuses or misleads through lack of standard performance metrics. This paper presents metrics of communication system performance which can be used to evaluate distribution line carrier systems when used over power distribution lines for automatic distribution functions such as load control, feeder automation, meter reading, and load survey. The emphasis in this paper is on fundamental quantities like throughput and residual error rate which are often used to measure the effectiveness of other data transmission systems and networks. A sample calculation of system requirements is included.

Residual error rate of binary linear block codes (Corresp.)

Transposing a computation of Mac Williams we derive an exact expression for, and a straightforward upper bound on, the residual error rate of a binary block code with a "standard" decoder. We also give series expansions for decoding error probability and residual error rates.

A forward error correction system for heavily disturbed data transmission channels

This paper describes a new forward error correction system suitable for protected data transmission on heavily disturbed transmission channels, such as radio channels or dialled telephone lines. The system consists of two independent coding stages, one designed to combat random errors due to a binomial distribution and the other to correct the remaining bursts. This configuration adapts the system to channels, which contain random errors as well as bursts. In addition, a signal quality detector and a device designed for channel status measurements control the two coding stages in a way to achieve optimum adaption of the decoders to the actual channel disturbances. The channel status measurement makes a better use of the redundancy of the burst error correction stage.Furthermore, the system&apos;s error detection characteristics avoid the delivery of data to the sink, which cannot be corrected with sufficient residual error probability with high security. Assuming a required residual error rate of Prest ̃ 10−8, random errors with error rates up to Pist ̃ 10−3 and bursts with lengths up to about 2900 bits are correctable.

Description of systems used for data transmission

Task Group X3.3.5 1 is working to develop proposals for standards relating to the performance of systems used for digital data transmission. It has published two tutorial papers which were submitted by the U.S.A. to the International Organization for Standardization. In the first paper—ISO/TC97/SC6(USA-7)30, 2 May, 1964—the general area of system performance was discussed. In the second paper, ISO/TC97/SC6 (USA-11)60, 3 March, 1965, discussed in some detail were two characteristics of system performance, namely, Transfer Rate of Information Bits (TRIB) and Residual Error Rate. The present paper, the task group's third tutorial paper, is devoted to “System Description” insofar as that topic relates to system performance. Reported are the results of some 14 discussions that have occurred in about 1 3/4 years (June 1964 through March 1966). Including normal turnover of personnel in the group, some 14 people have been involved in these discussions. At present, the members of the task group are associated with business equipment manufacturers, users groups, and suppliers of communication facilities and services in the proportions 5 to 3 to 1. Other groups have published papers which discuss system description. In April, 1965, a paper from Italy 4 was published in which system description was discussed in relation to line control and communication system techniques. In May, 1965, a paper from France 5 was published in which system description was discussed in relation to system performance. These papers have been an interesting source of information to X3.3.5. While considering system performance, X3.3.5 concluded that system performance standards cannot be developed and used fully without having an organized way of describing the hardware and conditions to which performance applies. While this may not be quite t

Effect of multipath propagation on performance of narrowband frequency-modulation radiotelegraph systems

An explanation is given of the high error rate and poor diversity action experienced with narrowband frequency-modulation radiotelegraph systems with fading multipath signals, even in the absence of noise. The mechanism of occurrence of these residual errors is examined in detail, and they are shown to be due to a combined effect of the frequency modulation and spurious amplitude modulation of the signal, which together cause severe phase aberrations during the signal transitions at troughs in the fading. The spurious amplitude modulation is due to the removal of the higher-order frequency-modulation sidebands by the normal channel filters, and it is shown that a useful reduction in the residual-error rate and improved diversity operation may be achieved if the second-order sidebands reach the output of the channel-receiving filter at their correct level. A method of establishing this condition in a multichannel system with practical filters is described, but it is concluded that some increase in channel spacing in relation to modulation rate would be necessary to restrict interchannel interference.