Stedman, R., Steele, R., Gharavi, H. and Hanzo, L.
A 22KBd Mobile Video Telephone Scheme.
of VTC'92, Denver, Colorado, U.S.A.,
10 - 13 May 1992.
This is the latest version of this item.
The complexity, image quality, bandwidth efficiency and robustness issues of a mobile video telephone scheme for personal communications networks (PCN) are addressed. Our motion-compensated 55 Kbit/s subband codec (SBC) using seven non-uniformly spaced active bands with band specific scanning and runlength coding achieves image peak signal to noise ratios (SNR) of around 38dB associated with good communications quality for monochrome common intermediate format (CIF) images sampled at 10 frames per second. The motion dependent bitrate fluctuations are smoothed out by buffering with adaptive quantiser control feedback. The video bits are then sorted into two sensitivity classes and error protected by a twin-class binary Bose-Chaudhuri-Hocquenghem (BCH) scheme. The separately BCH-encoded more significant bits (MSB) and less significant bits (LSB) are transmitted via separate subchannels of the 16-level quadrature amplitude modulator (16-QAM), having different integrity. The overall signalling rate becomes 22KBd, sufficiently low for typical microcells to fulfil the narrowband channel condition. Clearly, no equaliser has to be used, which considerably reduces the system’s complexity, yet unimpaired image quality is achieved for channel SNRs in excess of 20dB.
Available Versions of this Item
A 22KBd Mobile Video Telephone Scheme. (deposited 16 Jan 2003)
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