Unhee Park

A novel QO-STBC scheme with linear decoding for three and four transmit antennas

In this letter, we propose a quasi-orthogonal spacetime block coding (QO-STBC) scheme with maximum likelihood (ML) decoding via simple linear detection. A conventional QOSTBC scheme can achieve the full rate, but at the cost of decoding complexity and diversity gain. These disadvantages of the conventional QO-STBC scheme are mainly a result of interference terms in the detection matrix. In this letter, we propose a new QO-STBC scheme which eliminates interference terms. The proposed method achieves improved diversity gain with respect to the conventional QO-STBC scheme, as well as a great reduction in decoding complexity.

A new result on turbo coded QO-STBC schemes

In this letter, we present a new result on turbo coded quasi orthogonal space time block coding (QO-STBC) schemes. Proper utilization of soft decision information is one of the important factors affecting the performance of turbo codes. If a space time block coding (STBC) scheme is used with turbo codes, the output of the STBC decoder must be fed into a turbo code decoder as soft decision information. Therefore, the performance of turbo codes depends on how the STBC scheme generates soft decision information from its detection process. In this letter, we investigate the performance of turbo coded QO-STBC schemes, and present the optimum soft decision metrics.

Performance of turbo-coded QO-STBC schemes

This paper analyzes the relationship between soft decision detected values and the performance of turbo codes. Proper utilization of channel quality information is one of the important factors affects on the performance of turbo codes. If a space time block coding (STBC) scheme is used with turbo codes, the output of the STBC decoder should be fed into a decoder of turbo codes in the form of soft decision information. In this case, the channel quality information is contained in this soft decision information. Therefore, the performance of turbo codes is subject to how the STBC scheme generates soft decision information from its detection process. In this paper, we investigate a number of STBC schemes, and present suitable soft decision information for turbo codes. Simulation results show that a conventional QO-STBC scheme can highly degrade the performance of the turbo codes unless its soft detection information is carefully modified.

Evaluation of QO-STBC Schemes for Four Transmit Antennas

In this paper, we evaluate a few quasi-orthogonal space-time block coding (QO-STBC) schemes for four transmit antennas. Recently, QO-STBC with minimum decoding complexity (MDC-QO-STBC) was proposed. We provide a new analysis result on MDC-QO-STBC. We show that the encoding matrix of the MDC-QO-STBC is equivalent to the conventional QO-STBC. We also prove that this scheme can be linearly decoded at the receiver. This is achieved by modification of the encoding matrix via rotation of the channel correlation matrix.