Performance analysis of an improved multiple-access differential chaos shift keying

A new kind of multiple-access differential chaos shift keying (MA-DCSK) is presented which is based on the chaotic binary sequence and Walsh code. In the proposed system, the signals in the transmitter and the corresponding receiver are multiplied by the same Walsh code. Due to the constant instantaneous power of the chaotic binary signal and the Walsh code orthogonality, the interference between users will be greatly reduced. So, this kind of MA-DCSK has the multiple-access ability. The bit error rate (BER) performance is analyzed and the BER formula is evaluated. Simulation results match the numerical ones well, which supports the theoretical analysis. The performance is compared with that of other kinds of MA-DCSK in the additive white Gaussian noise (AWGN) channel. It is shown that the proposed MA-DCSK system is comparable to other MA-DCSK systems as all users use the different chaotic initial values. Compared to other MA-DCSK systems, the structure of the proposed system is simpler and more feasible to be implemented since the delays are invariant and the data to be processed is a kind of antipodal binary.