Space-time Block Coding Theory And Application Study In OFDM System

Space-time coding (STC), which jointly consider the design of coding,modulate, transmit and receive diversity technique, is one of the bestsolutions to providing high capacity, high data rare and high reliability.One kind of the codes, space-time block codes (STBC), which is alreadyproposed in the WCDMA system by 3GPP, is just the object discussed inthis dissertation. The basic theory of STBC and application thereof inOFDM mobile communication system are both studied.The decoding algorithm of STBC system has been studied. Accordingto the special orthogonal structure of STBC, a simplified decodingalgorithm of STBC-OFDM system is proposed. In addition, we haveanalyzed the performance of the STBC-OFDM system. It has shown thatthe system is in its ability to exploit all the available diversity resources,and the decoding algorithm of the system has a lower computingcomplexities.A QR factorization based blind estimation algorithm has been studied.In this paper, by combining the QR factorization based algorithm with thespecial structure of space-time block code, a new blind estimationalgorithm in STBC is proposed. Compared with the traditional blindestimation methods, the algorithm has much lower computational costs.And the Monte-Carlo simulations show that when the SNR is slow, thealgorithm is better than typical blind estimation methods.The quasi-orthogonal space-time block codes have been studied toabtain a complex orthogonal space-time block code that provides full diversity and full transmission rate. According to the theory of orthogonalmatrixes designs, this paper proposes a new rate-one space-time blockcode based on quasi-orthogonal design. And we also proposes a verylow-complexity maximum-likelihood (ML) detection algorithm based onQR decomposition. Simulation results show that the scheme has lowerBit Error Rate (BER) compared to the existing typical codes.