Electrical & Computer Engineering, Department of


Date of this Version



Published in Vehicular Technology Conference, 2004. VTC 2004-Spring. 2004 IEEE 59th Volume 3, 17-19 May 2004 Page(s):1490 - 1493 Vol.3 Digital Object Identifier 10.1109/VETECS.2004.1390501 Copyright 2004 IEEE. Used by permission.


The paper deals with the novel technique of designing complex spreading sequences with only four phases (0.25π, 0.75π, 1.25π, 1.75π). The interesting feature of those new sequences is the fact that not only the complex sequences are orthogonal but the real parts and imaginary parts are independently orthogonal. This can be utilized for spreading of complex constellation signals where the independent spreading using bipolar sequences (real part for in-phase component and imaginary part for quadrature component) can be applied. The paper introduces the theoretical background, and some example constructions of the amicable Hadamard matrices and the corresponding complex spreading sequences. The sequences are later modified using a diagonal method to achieve better correlation properties.