A New Full-Rate Orthogonal Space-Time Block Coding Scheme Based on Quaternion
This paper introduces a full rate, full diversity orthogonal space-time block code for 4 transmit antennas. The4times4 codeword matrix consists of four 2times2 Alamouti blocks, and these blocks can be viewed as quaternions which in turn represent rotations in R3. The Alamouti blocks that appear in a codeword are drawn from the icosahedral group. The code is no constellation expansion unlike some full-rate full-diversity codes in the literature. By utilizing the quaternionic form, we can find the decoding algorithm to reduce the complexity of maximum likelihood (ML) coherent decoding.