Cyclic Delay Diversity is a diversity scheme

Diversity scheme

In telecommunications, a diversity scheme refers to a method for improving the reliability of a message signal by using two or more communication channels with different characteristics. Diversity plays an important role in combatting fading and co-channel interference and avoiding error bursts...

 used in OFDM-based telecommunication systems, transforming spatial diversity into frequency diversity avoiding intersymbol interference

Intersymbol interference

In telecommunication, intersymbol interference is a form of distortion of a signal in which one symbol interferes with subsequent symbols. This is an unwanted phenomenon as the previous symbols have similar effect as noise, thus making the communication less reliable...

.

CDD was introduced in 2001 and can gain frequency diversity at the receiver without changing the SISO receiver structure.

The idea of CDD for OFDM had previously also been submitted as a patent application in September 2000.