H.264 Transmission Scheme Based On Precoding Technique Over Space-time Coding System

With the development of economy, advancement of society and improvement of people's standard of living, new generation wireless communication systems are expected to provide higher transmission rate, offer better quality and support faster moving terminals. The most effect way to meet such requirements is the MIMO technology, which deploys multiple antennas at transmitter and/or receiver. Recent research in information theory has shown that larger gains in the capacity of channels are feasible in MIMO systems. To make full use of the capacity of MIMO channels, space-time coding is a set of practical signal techniques when there is no channel state information (CSI) at the transmitter. As a new generation of video compression coding standard, H.264/AVC has been a hot issue of researchers at home and abroad, because of its excellent coding efficiency and strong ability to adapt a variety of networks. In an addition, H.264 bit stream has strong error resilience, which will adapt to many applications of wireless network. Therefore, the combination of MIMO system and H.264/AVC will greatly enhance the multimedia communication reliability. In order to achieve a QoS guaranteed video transmission over wireless channels, there are many error resilience technologies used in H.264/AVC to improve video stream adaptability to the networks. This dissertation mainly concentrates on the space-time codes and the H.264/AVC transmission, and it includes:(1) The H.264 encoded bit stream is divided into two parts according to its importance. One includes important information, which is PPS SPS and I or IDR frames, and the other includes the remaining data.(2) An improved H.264/AVC transmission scheme based on precoding technique and its implementation are proposed, which can achieve a higher coding gain instead of increasing total power over wireless fading channels over STBC system. H.264 coded information is divided into two parts according to their different importance, each part is transmitted differentially based on precoding technique over STBC system to achieve unequal error protection. Simulation results show that the scheme can obviously improve the bit error resilience compared to traditional two antennas STBC system, especially when the channel is in bad condition. It yields improvements in average PSNR of up to 7 dB compared to the traditional two antennas STBC system.(3) In the fourth chapter, we introduced the group space time coding (GSTBC) system based on space time block codes system. The GSTBC can achieve good tradeoffs between the transmission rate and high diversity. For the GSTBC, it is a good choice for using the Alamouti encoding program in each group, not only guarantees a high rate, but also achieves a high system performance. In addition, the chapter also describes the space time trellis codes (STTC) and full-diversity full-rate (FDFR) space time codes.