Improving the Performance of a Low-rate Image Coder Connected to a Noisy Gaussian Channel.

The problem of communicating the output of a vector quantizer image coder over Gaussian channel is investigated. A fixed bandwidth is assumed to be available and the energy per modulator symbol is fixed. The reference system is a QPSK modulator with a gray code mapping between bits and modulator symbols. The techniques investigated include Hamming coding, convolutional coding, 8-PSK trellis-coded modulation, and methods based on simulated annealing coupled with quantizer optimization