Space-time coded transmission schemes on wireless channels

Highly reliable and fast wireless communication services demand the communication channel capacity to be fully exploited. Vast amount of research effort have been expanded in the development of advance technologies, such as signal processing, channel coding, modulation/demodulation, diversity techniques, and so on.This thesis focuses on the development of space-time coded transmission schemes. In order to provide high diversity gain with minimum design complexity, we propose a closed-loop beamforming transmission technology combined with existing simple channel coding method. We show that this coded beamforming scheme can achieve full diversity as the space-time coding technique does for a multiple-antenna system, while significantly reducing the design complexity.It is normally impractical to install multiple antennas on a small wireless communication device. We therefore further our research to cooperative communication, in which single-antenna communicators share their antennas with partners in information relay, so that the benefit of multiple-antenna transmission can be achieved for the singleantenna users. We analyze the system performance for the typical decode-and-forward user cooperative system, formulate the code design criteria, and construct optimal codes. To simplify the system design, we introduce estimate-and-forward protocol with differential modulation scheme. In order to ensure the practicality of the system design, we introduce an equivalent link model to replace the source-relay-destination link, taking into account the imperfect detections at the relay. Finally we extend the analysis to a multiple-relay system using selective combiner at the destination