Hierarchical Multimedia Transmission Using Multilayered Space-time Trellis Codes

摘要

Hierarchical multimedia transmission in multiple-input and multiple-output (MIMO) system is researched. In MIMO system, the structure of multilayered Space-time Trellis codes (ML-STTC) has been proposed by combining array processing with Space-time Trellis code (STTC), the complexity of which is dramatically reduced by partitioning the transmit antennas into several layers. In this paper, a system architecture based on ML-STTC is constructed for image transmission, which performs as a compromise between data rate and reliability. In this architecture, the progressive data stream coded by set partitioning in hierarchical trees (SPIHT) is divided into several sub-streams according to their importance. Then a novel unequal error protection (UEP) scheme integrated with ML-STTC is proposed by optimizing the sub-stream allocation. Further more, the UEP scheme is strengthened by the ordered array processing at the receiver. In this way, the peak signal-to-noise ratio (PSNR) performance can be significantly enhanced in an environment with a moderate range of signal-to-noise ratio (SNR). In addition, the proposed transmission architecture and hierarchical transmission schemes can easily be extended to video communication systems with MPEG-4 or H.264 etc.