Coded Modulation
 

• It is a technology of combining bandwidthefficient modulation and coding to achieve coding gain without bandwidth expansion or reducing data rate.

• The basic concept of this technology is to perform coding onto an expanded modulation signal set (relative to that needed for uncoded transmission).

• The redundancy needed for error control comes from signal expansion (or from both signal expansion and coding).

• Coding is used to from structured signal sequences with large minimun Euclidean distance.

• This combination of coding and modulation into an integral part in called coded modulation.

• It finds applications on bandlimited channels such as voiceband telephone, terrestrial microwave, satellite and mobile channels.