Design of Multiple Turbo-Coded modulation diversity

In this paper, a scheme of modulation diversity with multiple turbo codes is studies. Rotation of the signal constellation together with in-phase and quadrature channel interleaving is known to prove good performance gains over fading channels for multi level modulation methods. Recently it has been shown that multiple turbo codes with very simple sub-codes outperform conventional 2-parallel turbo codes. It is shown that for a multiple turbo-coded Gray mapped MPSK modulation diversity over Rayleigh fading channel, a well selected rotation angle may lead to a significant gain over the conventional un-rotated constellation.