The complexity robustness, image and speech quality as well as packet multiplexing issues of a re-configurable multi-media mobile communicator are addressed. The proposed moderate complexity motion-compensated discrete cosine transform (DCT) based image communicator provides an image peak signal-to-noise ratio (PSNR) of 38 dB at an average bit rate of about 25 kbits/s. The speech codec used is a low-complexity 32 kbit/s CCITT G721 standard scheme. Bandwidth efficient 16 or 64-level quadrature amplitude modulation (QAM) combined with embedded low-complexity binary Bose-Chaudhuri-Hocquenghem (BCH) forward error correction (FEC) coding is deployed. The 2O-slot packet reservation multiple access (PRMA) scheme used supports an extra 2.4 kbit/s low-rate data channel for each speech user, in addition to providing 5-6 videophone channels. The ADPCM/DCT/BCH/16-QAM and ADPCM/DCT/BCH/64-QAM schemes provide nearly unimpaired speech and image quality for channel SNRs in excess of 30 dB and 38 dB, respectively. >
['Lajos Hanzo', 'R. Stedman', 'R. Steele', 'J.C.S. Cheung']
A mobile speech, video and data transceiver scheme