Multipriority video transmission for third-generation wireless communication systems

This paper presents a robust dual-priority video partitioning method suitable for twin-class unequal protected video transmission over wireless channels. The partitioning is based on a separation of the variable-length (VL) coded discrete cosine transform (DCT) coefficients within each block. The scheme is suitable for constant bit-rate transmission (CBR), where the fraction of bits assigned to each of the two partitions can be adjusted according to the requirements of the unequal error-protection scheme employed. The distribution of the VL-coded (VLC) information between the two partitions is performed adaptively. Subsequently, the partitioning method was applied to the ITU-T H.263 coding standard. It was shown that, for the input video with quarter common intermediate format (QCIF) spatial resolution (or less), the partitioning overhead can be embedded in the B-bit code word representing the group number (GN), thus avoiding transmission of additional bits. As a transport vehicle, we have considered one of the leading third generation cellular radio standards known as wide-band code division multiple access (W-CDMA). A dual-priority transmission system is then invoked on the W-CDMA system where the video data, after being broken into two streams, are unequally protected. We use a very simple error-correction coding scheme for illustration and then propose more sophisticated forms of unequal protection of the digitized video signals. We show that this strategy results in a significantly higher quality of the reconstructed video data when they are transmitted over time-varying multipath fading channels.