Error detection and optimum decoding for line codes in digital transmission systems

It is important for the communication link to detect random errors caused by noise, interference and crosstalk or caused by other impairments, so that the fault can be rectified. For this reason, error detection is a vital part of a transmission link. When errors have been detected, it is important for the decoder to minimize their effect or to ensure that they do not cause further errors. This paper introduces various methods to evaluate the performance of a digital transmission system at the receiving terminal. Optimization techniques to construct the decoding maps for line codes are also investigated. They help the designers to predict the error rate in the decoded data assuming the transmission error rate is given. The predicted error rate is based on the error extension factor for the line code. Thus, the paper presents the methodology technique to obtain this factor for most line codes. It depends on the statistics of the transmitted data and the decoding map for the code.