EDUCING TO F AULT E RRORS IN C OMMUNICATION C HANNELS S YSTEMS 1 Shiv

In this paper we introduce error-control techniques for improving the error-rate performance that is delivered to an application in situations where the inherent error rate of a digital transmission system is unacceptable. The acceptability of a given level of bit error rate depends on the particular application. For examples, certain types of digital speech transmission are tolerant to fairly high bit error rates. Other types of applications such as electronic funds transfer require essentially error-free transmission. For example, FEC is used in the satellite and deep-space communications. A recent application is in audio CD recordings where FEC is used to provide tremendous robustness to errors so that clear sound reproduction is possible even in the presence of smudges and scratches on the disk surface.