Article

# Design and Performance Analysis of Quasi-Orthogonal Space-Time Block Codes for Four Antennae

01/2005; DOI: 10.1093/ietfec/e88-a.11.3244

Source: OAI

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**ABSTRACT:**We consider cooperative networks of one source, four relays, and one destination. Each of them has a single antenna. The four relays use a proposed full rate distributed quasi orthogonal space time block code (DQOSTBC) scheme. If the channel state between the source and a relay is above a threshold, we select the elements of the DQOSTBC matrix to be the decode-and-forward (DAF) type; if it is below the threshold, the corresponding elements are the amplify-and-forward (AAF) type. Thus the proposed scheme is a DQOSTBC matrix with embedded adaptive DAF/AAF elements. The bit error rate (BER) simulation results show that the proposed DQOSTBC is approximately 7 dB better than the traditional DQOSTBC (all matrix elements are fixed as DAF type) at a BER of $10^{-3}$ because traditional DQOSTBC loses full diversity due to errors in the information received. The proposed DQOSTBC is about 3 dB better than the rate 1/2 DOSTBC also proposed with adaptive DAF/AAF matrix elements at a BER of $10^{-3}$ at the same spectral efficiency of 2 bits/s/Hz.Wireless Personal Communications 03/2014; 75(2). · 0.43 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**By studying the super-orthogonal space-time coding designs for 2 transmit antennas and superquasi orthogonal space-time coding designs for 4 transmit antennas, a novel super-orthogonal space-time coding design for 4 transmit antennas is proposed. By exploiting the inherent structure association between OSTBC and QOSTBC, the proposed schemes can obtain the full-rate and good performance while keeping the coding complexity as super-orthogonal space-time coding schemes for 2 transmit antennas. Simulation results demonstrate that the proposed schemes outperforms the existing super-quasi orthogonal space-time coding schemes by almost 2 dB.Sciece China. Information Sciences 01/2011; 54:1481-1490. · 0.71 Impact Factor - [Show abstract] [Hide abstract]

**ABSTRACT:**During the last few years, a number of Quasi-Orthogonal Space-Time Block Codes (QOSTBC) have been proposed for using in multiple transmit antennas systems. In this letter, based on circulant matrix, we propose a novel method of extending any QOSTBC constructed for 4 transmit antennas to a closed-loop scheme. We show that with the aid of multiplying the entries of QOSTBC code words by the appropriate phase factors which depend on the channel information, the proposed scheme can improve its transmit diversity with one bit feedback. The performances of the proposed scenario extended from Jafarkhani's QOSTBC as well as its optimal constellation rotated scheme are analyzed. The simulation results suggest that there is a significant Eb/No advantage in the proposed scheme which is able to be designed easily.IEEE Transactions on Wireless Communications 01/2009; 8:3386-3389. · 2.42 Impact Factor

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