ABSTRACT
The performance improvement that occurs when using an error control coding is often measured in terms of coding gain. Suppose an uncoded communications system achieves a given bit error rate (BER) at a signal-to-noise rate (SNR) of 35 dB. Imagine that an error control coding scheme with a coding gain of 3 dB was added to the system. This coded system would be able to achieve the same BER at the even lower SNR of 32 dB. Alternatively, if the system was still operated at an SNR of 35 dB, the BER achieved by the coded system would be the same that the uncoded system achieved at an SNR of 38 dB. The power of the coding gain is that it allows a communications system to either maintain a desired BER at a lower SNR than was possible without coding, or achieve a higher BER than an uncoded system could attain at a given SNR [LIT200101].
