Interference Cancellation and Space-Time Block Codes in Frequency Selective Multiple-Access Channels

Space-time block codes (STBC) make use of a rich algebraic structure to provide diversity gains with small decoding complexity. In this paper, different reduced complexity sub-optimum equalizers have been designed utilizing the rich signal structure of space time block codes (STBC) and their performance has been studied. A frequency selective multiple access environment has been used for all the analysis. We exploit the structure of time reversed STBC (TR-STBC) and design different equalizers in the time domain. Then, we shift our attention to the frequency domain where equalizer computation becomes less complex due to the use of the fast Fourier transform (FFT) algorithm and the special algebraic signal structure of STBC. In both domains, performance of such equalizers was studied first in the single user case, and then was extended to multiuser cases.