Rate 1 space-time and space-frequency spreading diversity technique

Authors: GÖKÇE HACIOĞLU, ALİ GANGAL

Abstract: In this study, a rate 1 transmitter diversity technique is proposed. The proposed technique uses spreading transform and space-time block coding (STBC) together. Space-time, space-frequency, and frequency diversity applications of the proposed technique are shown. The code matrix of the proposed technique can be designed systematically. The proposed technique needs the channel coefficients to stay constant over transmission of 2 rows of the coding matrix regardless of the size of the coding matrix or the diversity order. However, joint detection of the symbols is required for the proposed technique. We used computer simulations to compare our technique with the quasi-orthogonal space-time block coding (QOSTBC), orthogonal space-time block coding (OSTBC), and spreading transform diversity methods. The results showed that the proposed technique provides higher SNR-BER gain than OSTBC and spreading transform diversity, and can provide a higher gain than QOSTBC for time-varying channels. The proposed technique is less sensitive to the time selectivity of the channel than QOSTBC or OSTBC. The detection complexity of the proposed technique is lower than that of spreading diversity.

Keywords: Diversity, space-time coding, space-frequency coding, carrier spreading, OFDM

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