Multi-Priority Video Transmission for Third Generation Wireless Communication Systems
Hamid Gharavi, S M. Alamouti
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 bitrate 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 amongst 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 QCIF spatial resolution (or less), the partitioning overhead can be embedded in the 5-bit codeword 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 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, is 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 will show that this strategy results in a significantly higher quality of the reconstructed video data when it is transmitted over time-varying multipath fading channels.
Mobile Multimedia Applications
106 No. 2
multimedia communications, video compression and error resilience c, wireless