The effects of rotated constellation techniques in DVB systems

Rotated constellation techniques are usually employed for digital video broadcasting (DVB) to provide modulation diversity for M-PSK and M-QAM modulations over fading channels. Constellation rotation is usually coupled with interleaving the real and imaginary components of transmitted symbols either in time or frequency domain. If one of these components is subjected to fading or interference, it may still be possible to recover the symbol at the receiver by using the information provided by the other component. This technique is shown to offer much improved performance when used together with RS and convolutional coding used in terrestrial DVB systems.