ABSTRACT

The transmission of information over a communication system always results in some degradation in the quality of the information. In digital links, degradation of the information content of a signal is measured in terms of the bit error rate. A fundamental difference between analog and digital signals is that we can increase the bit error rate of a digital signal by the use of error correction techniques. No such techniques is available for analog signals since once the information is contaminated by noise, it is extremely difficult to remove the noise, as we cannot in general distinguish between the signal and the noise electronically. In a digital system, we can add extra redundancy bits to our data St earn, which can tell us when an error occurs in the data and can also point to lie particular bit or bits that have been corrupted. Coding theory refers to error-detection or correction. This implies that additional (redundant) bits are added to the data stream to form error-detecting or error correcting codes. Finally, the decoder (receiver) works with various decoding techniques using Abstract Algebra to be able to detect and correct errors in a given data stream. These techniques are software implemented and are basically algorithms.