  This paper carries out the first-ever investigation of the analysis of a
cooperative Decode-and-Forward (DF) relay network with Chaos Shift Keying (CSK)
modulation. The performance analysis of DF-CSK in this paper takes into account
the dynamical nature of chaotic signal, which is not similar to a conventional
binary modulation performance computation methodology. The expression of a
lower bound bit error rate (BER) is derived in order to investigate the
performance of the cooperative system under independently and identically
distributed (i.i.d.) Gaussian fading wireless environments. The effect of the
non-periodic nature of chaotic sequence leading to a non constant bit energy of
the considered modulation is also investigated. A computation approach of the
BER expression based on the probability density function of the bit energy of
the chaotic sequence, channel distribution, and number of relays is presented.
Simulation results prove the accuracy of our BER computation methodology.
