16-k bps modem design using vector quantization

Abstract

It is pointed out that, by reversing the order of the encoding and decoding process, vector quantization (VQ) can be used as a binary-input/analog-output coder to transmit binary messages across analog channels. As compared with traditional modem schemes, VQ offers higher transmission rates for a fixed SNR (signal to noise ratio) or lower SNRs for a fixed transmission rate. The initial simulation efforts, written in F77, used the AWGN (additive white Gaussian noise) channel with low dimensions (1-8) and data rates of 1-3 bits/sample or, equivalently, 8000-24000 bits/s. The research strategy involves the following: upgrading the VQ modem algorithm, channel modeling and computer simulation of higher dimension, system performance simulation, and development of a VQ model system. Simulations of higher dimension sizes (8-16) are written in C programming language, and by using the VQ modem algorithm with AWGN 3.2 kHz channels, transmission rates of 16 kbit/s are achievable across 'average' telephone lines. >