Throughput of ADSL modems

IEEE Communications Magazine, 2004

IEEE Transactions on Communications, 2000

Absrracr-In this paper we investigate the bit error rate (BER) performance of a passband single-carrier QAM transceiver for Asymmetric Digital Subscriber Lines (ADSL), with additive white Gaussian noise (AWGN) and sell far-end crosstalk (FEXT) as the main disturbances. The major difference with previous contributions on ADSL performance Is that we present a simple approximate analytical expression for the signal-to-noise ratio (SNK) margin, which clearly shows the effect of various cable and system parameters (such as loop length, transmit power, QAM constellation size, bit rate, ...) on ADSL performance. From this expression, we determine the optimum constellation size and the maximum achievable bit rate as a function of the loop length.

This paper proposes an approach that utilizes a new forward error correction mechanism for reconstructing lost or corrupted packets sent over a Network. Instead of retransmissions of lost or corrupted packets, the new approach depends on sending extra packets with each group of packets in order to reconstruct lost or corrupted packets. This approach is based on applying a high-performance irregular array code called REA for tolerating up to two lost packets. If the numbers of losses is more than 2, Go-Back-N automatic repeat request (ARQ) mechanism is used. This approach is useful for improving the performance of TCP over less reliable communication links like wireless networks. The paper employs a hybrid approach that takes advantage of and efficient erasure code at the link layer for error correction together with packet recovery through retransmission to enhance the system performance. The paper presents simulation results that evaluate the effectiveness of the proposed approach.

2009 3rd International Conference on New Technologies, Mobility and Security, 2009

In this paper a new approach is proposed to increase the performance of the operation of error control on data transmission. Specifically, a hardware structure for parallel Cyclic Redundancy Check (CRC) calculation is developed to speed up the error control operation of data transmission. Based on a study of the properties of both CRC and Check Sum (CS) a new error detecting scheme is developed which combines CRC and CS. Also it is shown that the proposed error detecting scheme ensures high reliability and performance of the error control operation on data transmission in comparison to CRC alone.

IEEE Communications Magazine, 2000

In any system that handles large amounts of data, uncorrected and undetected errors can degrade performance, response time, and possibly increase the need for intervention by human operators Aprll 4987-Vol. 25, No. 4 IEEE Communlcatlonr Magazine E rror Control is an area of increasing importance in communications. This is partly because the issue of data integrity is becoming increasingly important. There is downward pressure on the allowable error rates for communications and mass storage systems as bandwidths and volumes of data increase. Certain data cannot be wrong; for example, no one can be complacent about the effect of an undetected data error on a weapons control system. More generally, in any system which handles large amounts of data, uncorrected and undetected errors can degrade performance, response time, and possibly increase the need for intervention by human operators.

A popular approach to designing high-speed modems for use on voice-grade telephone channels is to use a high order modulation scheme combined with a digital architecture. This paper describes the development of a modem structure which uses the DSP56001 signal processor to implement 49 quadrature partial response signalling (49 QPRS). The choice of 49 QPRS is justified by its high spectral efficiency and reasonable error rate performance. This system is being developed for two applications, which are described in the paper.

International Journal of Power Electronics and Drive System (IJPEDS), 2018

A concept of data transmission within downhole telemetry systems in oilfield industry through power lines is presented. Based on this concept, MATLAB/Simulink models simulating communication lines in downhole telemetry systems are built, which can be used as prototypes for development of real systems. The most appropriate signal modulation methods for data transmission in downhole telemetry systems are suggested and discussed. The influence of high-voltage interference on signal transmission through power line from downhole unit to ground based unit is simulated. Usage of error-correcting coding methods for data transmission such as Hamming code, Reed-Solomon code, BCH code is suggested, and its efficiency is demonstrated

… Engineering & Systems …

IEEE Transactions on Communications, 1993

The performance of the SNR protocol of A. N. Netravali et al. (1990) is studied when it is implemented for end-to-end flow and error control. Using a combination of analysis and simulation, the efficiency with which this protocol uses the network bandwidth and its achievable throughput is evaluated as a function of certain network and protocol parameters. The protocol is enhanced by introducing two windows to decouple the two functions of receiver flow control and network congestion control. This enhancement and the original protocol are compared with go-back-N (GBN) and one-at-a-time-selective-repeat (OSR) retransmission procedures, are shown to have significantly higher throughput for a wide range of network conditions. As an example, for a virtual circuit with 60-ms roundtrip delay and 10-8 bit error rate, in order to deliver 500 Mb/s throughput, both the GBN and OSR require a raw transmission bandwidth of approximately 800 Mb/s, whereas SNR with two windows needs slightly higher than 500 Mb/s raw bandwidth. Periodic exchange of state can also provide a variety of measures for congestion control in a timely and accurate fashion

ijmra.us

During digital data transmission in digital communication system, noise is added and physical defects in the communication medium can cause random errors during data transmission. Error coding is a method of detecting and correcting these errors to ensure information is transferred intact from its source to destination. Error coding is used for fault tolerant computing in computer memory, magnetic and optical data storage media, satellite and deep space communications, network communications, cellular telephone networks, and almost any other form of digital data communication. Error coding uses mathematical formulas to encode data bits at the source into longer bit words for is transmission. Decoding of the code word is possible at side of receiver. The extra bits in the code word provide redundant bit, according to the coding scheme used, will allow the destination to use the decoding process to determine if the communication medium's expected error rate, signal to noise ratio and whether or not data retransmission is possible. Faster processors and better communications technology make more complex coding schemes, with better error detecting and correcting capabilities, possible for smaller embedded systems, allowing for more robust communications. The proposed title discloses a novel approach for detection and correction of binary stream transmission errors such as random errors and bursts errors in digital communication systems. The fault detection and correction will be accomplished by Linear Block Code, Convolution Code or concatenated Code Error-Control Coding techniques.