TITLE:
A Design Method of Noncoherent Unitary Space-Time Codes
AUTHORS:
Li Peng, Qiuping Peng, Lingling Yang
KEYWORDS:
Noncoherent Uintary Space-Time Codes (N-USTC), Coherent Space-Time Codes (C-STC), Grassmann Manifold, Degree of Freedom, Exponenatial Map, Full Rate and Full Diversity (FRFD)
JOURNAL NAME:
International Journal of Communications, Network and System Sciences,
Vol.4 No.7,
July
11,
2011
ABSTRACT: We generalized an constructing method of noncoherent unitary space time codes (N-USTC) over Rayleigh flat fading channels. A family of N-USTCs with T symbol peroids, M transmit and N receive antennas was constructed by the exponential mapping method based on the tangent subspace of the Grassmann manifold. This exponential mapping method can transform the coherent space time codes (C-STC) into the N-USTC on the Grassmann manifold. We infered an universal framework of constructing a C-STC that is designed by using the algebraic number theory and has full rate and full diversity (FRFD) for t symbol periods and same antennas, where M, N, T, t are general positive integer. We discussed the constraint condition that the exponential mapping has only one solution, from which we presented a approach of searching the optimum adjustive factor αopt that can generate an optimum noncoherent codeword. For different code parameters M, N, T, t and the optimum adjustive factor αopt, we gave the simulation results of the several N-USTCs.