Bit Error Rates

Abstract

A practical consideration that has so far received little attention is the correcting power of the coding required to do the job. In other words, if we need a certain improvement in channel performance, how many bits must we be able to correct? This aspect of the subject gets quite mathematical, so I shall give only a simplified view of the problem in keeping with my overall aim of minimizing the maths. The quality of a channel is often defined in terms of its bit error rate, or BER. This is a measure of how likely a bit is to be in error. A digital mobile telephone inside a building will experience a raw BER of about 10⁻². This simply means that on average, one bit in 100 will be in error, or the probability that any bit will be incorrect is 0.01. Given a system requirement for a certain BER, we can see how much work the error coding needs to do.