Backward Error Detection
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View all reference sources FREE REFERENCE ENTRIES A B C D E F G H I J K L M N O P Q R S T U V W X Y Z error detection and correction # Home Dictionaries, Thesauruses, Pictures, and Press Releases A Dictionary of Computing January error detection and correction in computer networks 2004 backward error correction Print this article Cite this article Tools A Dictionary of Computing | 2004 | 700+
Error Detection And Correction Using Hamming Code Example
words © A Dictionary of Computing 2004, originally published by Oxford University Press 2004. backward error correction (backward correction) Error correction that occurs in a channel through the detection of errors by the
Crc Error Detection
receiver: the receiver responds to any errors in a block by requesting the transmitter to retransmit the affected block. Backward correction requires a return channel, by contrast with forward error correction.There are two ways in which the return channel can be used to indicate errors: positive acknowledgment and negative acknowledgment. With positive acknowledgment, the receiver returns confirmation of each block received correctly, and the transmitter is error detection and correction in data link layer prepared to retransmit a block that is not acknowledged within an appropriate time. With negative acknowledgment, the receiver returns a request to retransmit any block received erroneously, and the transmitter is prepared to retransmit such a block (implying that the transmitter retains a copy of every block sent, indefinitely).Since the return channel itself may be prone to errors, and to limit the amount of storage necessary at the transmitter, the positive acknowledgment and retransmission (PAR) technique is generally preferred. See also error-detecting code. Cite this article Pick a style below, and copy the text for your bibliography. MLA Chicago APA JOHN DAINTITH. "backward error correction." A Dictionary of Computing. 2004. Encyclopedia.com. 1 Oct. 2016
control. There are different communications media with different quality of service (QOS). Consequently, there are several error detection and control schemes for different signal conditions. Some fundamental methods have existed for decades. In addition, there are also new methods that can take
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advantage of the nature of the signal type. These methods can be used to ensure error correction reliable or adequate communications and faster data transfer rates which are used in today's innovative applications. 1. Error sources No errors can occur error detection and correction pdf in the ideal transmission medium. However, none of the transmission media is ideal. The signal representing the data is always subject to various error sources. As the signal propagates along the transmission media its amplitude decreases. This http://www.encyclopedia.com/doc/1O11-backwarderrorcorrection.html phenomenon is called as the signal attenuation. The signal cannot be detected if it is too weak. In addition, as the length of the medium increases the waveform also changes during the transmission. This phenomenon is called as the delay distortion. The signal cannot be recognized if it is too distorted. Furthermore, the transmission media can also be a subject to interference resulting from other cables or signals caused by electromagnetic radiation. The medium itself may http://www.tml.tkk.fi/Studies/Tik-110.300/1998/Essays/error_detection.html also cause constant white noise. All transmission errors increase as the length of the transmission medium inreases. [6] 2 Error bursts In practice, data communications systems are designed so that the transmission errors are within acceptable rate. Under normal circumstanced there are only few errors. However, it is possible that the signal conditions can be sometimes so weak that sometimes the signal cannot be received at all. It is also possible that sometimes the interference signal is stronger than the signal to be transmitted. Consequently, the data sent during the break is lost. The contiguous blocks of data corrupted by the error signal are called error bursts. The length and frequency of the error bursts depend on the quality of the data link which in turn depends on the transmission medium and the signal conditions. Therefore, the error detection and control should be able to handle as many errors that possible. However, the applications limit which error detection and control schemes are suitable. All applications benefit from the effeciency of the sheme to be used. In addition, some applications may require short codeword length or low latency whereas some other applications might prefer extremere low error rate, for example. 3 Error detection Error detection is a method that allows some sommunications erros to be detected. The data is encoded so that the encoded dat
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