A wireless multimedia system

The complexity, robustness, image and speech quality as well as packet multiplexing issues of a reconfigurable 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 64level quadrature amplitude modulation (QAM) combined with embedded low-complexity binary Bose-Chaudhuri-Hocquenghem (BCH) forward error correction coding is deployed. The 20-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 video-phone channels. The ADPCM/DCT/BCH/16-QAM as well as 64QAM schemes provide nearly unimpaired speech and image quality for channel SNRs in excess of 30 dB and 38 dB, respectively