A novel coding scheme for the transmission of on-line handwriting

The proposed adaptive fixed-length differential chain coding (FL-DCC) scheme can be configured as a lower rate, lower resolution or higher rate, higher resolution source codec. The programable-rate FL-DCC codec is embedded in an adaptive transceiver invoking more bandwidth efficient 16-level quadrature amplitude modulation (16 QAM) over benign microcellular channels, while employing more robust 4 QAM in more hostile propagation scenarios. The minimum required channel signal to noise ratio (SNR) over AWGN and Rayleigh channels in its 16 QAM mode is about 11 and 15 dB, respectively and the low-rate graphical stream can be accommodated during silent speech spurts.