  In this paper, multiplexing of discrete chaotic signals in the presence of
noise is investigated. Existing methods are based on chaotic synchronization
which is susceptible to noise and parameter mismatch. Furthermore, these
methods fail for multiplexing more than two discrete chaotic signals. We
propose two novel methods to multiplex multiple discrete chaotic signals based
on the principle of symbolic sequence invariance in the presence of noise and
finite precision implementation of finding the initial condition of an
arbitrarily long symbolic sequence of a chaotic map.
