Joint source-channel coding using space-filling curves for bandwidth compression

Abstract

Summary form only given. By jointly optimizing source and channel codes, we can generally get less overall average distortion and more robustness to channel impairments than with separately designed source and channel codes. In many cases, however, it is difficult or sometimes impossible for a single coding scheme to achieve the least possible distortion for a large range of channel variations except the trivial Gaussian case, where the rate distortion bound on the mean square error is achieved for all values of the channel signal to noise ratio (SNR) when the i.i.d. Gaussian source and the additive white Gaussian noise (AWGN) channel have the same bandwidth. In this paper, we show that a simple uncoded system that transmits an unmodified uniform i.i.d. source defined on the unit interval I=[0,1] through a modulo AWGN channel (an AWGN channel followed by a mod-1 mapping such that the channel output is the fractional part of the AWGN channel output) can achieve the rate distortion bound almost optimally for all values of the channel SNR.