Quaternion Modulation for Dual-Polarized Antennas

This letter presents a new modulation scheme for dual-polarized antennas based on the theory of quaternion. First, we introduce the concept of quaternions to represent states of polarized antennas and data transmission. Second, we describe a detector based on the quaternion expression for polarized wireless systems and its corresponding theoretical performance. Compared with the spatial multiplexing scheme, the proposed scheme is more energy efficiency. On the other hand, the scheme can generate more benefits than the spatial modulation scheme in terms of the spectral efficiency. Therefore, the scheme provides a tradeoff between spectral- and energy-efficiency, making it an excellent candidate for future wireless communications systems.