Diversity techniques are commonly used in wireless communications to combat multipath fading. Recent interests in ultra-wideband technology focus on multi-band OFDM systems that can explore the high diversity due to the independent frequency bands. To achieve full diversity with high data rate, a system, apparatus and method that uses coded modulation with spreading rotation of transmitted signals. A 2×2 integer rotation matrix for QAM signals, 3×3 and 4×4 integer rotation matrices for QAM signals are provided. Compared with the non-regular QAM shape for real rotation matrices, each of these integer rotation matrices makes the regular QAM shape after rotation.