Summary: 1450 IEEE TRANSACTIONS ON INFORMATION THEORY, VOL. 52, NO. 4, APRIL 2006
On the Joint Source­Channel Coding Error Exponent
for Discrete Memoryless Systems
Yangfan Zhong, Student Member, IEEE, Fady Alajaji, Senior Member, IEEE, and L. Lorne Campbell, Life Fellow, IEEE
Abstract--We investigate the computation of Csiszár's bounds
for the joint source­channel coding (JSCC) error exponent
of a communication system consisting of a discrete memoryless
source and a discrete memoryless channel. We provide equivalent
expressions for these bounds and derive explicit formulas for the
rates where the bounds are attained. These equivalent representa-
tions can be readily computed for arbitrary source­channel pairs
via Arimoto's algorithm. When the channel's distribution satisfies
a symmetry property, the bounds admit closed-form parametric
expressions.Wethenuseourresultstoprovideasystematiccompar-
ison between the JSCC error exponent and the tandem coding
error exponent , which applies if the source and channel are
separately coded. It is shown that 2 . We establish
conditions for which and for which = 2 . Nu-
merical examples indicate that is close to 2 for many source­
channel pairs. This gain translates into a power saving larger than

Source: Alajaji, Fady - Department of Mathematics and Statistics, Queen's University (Kingston)

Collections: Engineering