An Integrated Chaotic Transceiver for Spread-Spectrum Radar and Communications

This paper introduces an integrated chaotic transceiver for spread-spectrum communication and radar systems. The design uses a broadband transmitter based on a chaotic oscillator that combines a continuous differential equation with a discrete switching condition. This hybrid oscillator admits an analytic solution that is a linear convolution of symbol sequences and basis functions. A tunable analog matched filter circuit is designed for this basis function and used to implement an optimal coherent receiver to extract symbolic sequences from the chaotic waveform. The proposed chaotic transmitter and coherent receiver are then used to implement a simple on-off-keying (OOK) communication scheme. The proposed analog matched filter continuously outperforms a conventional Butterworth low-pass filter in an additive white Gaussian noise (AWGN) channel. Specifically, simulation results in a 180 nm CMOS process show an average improvement of similar to 3.0 dB in signal-to-noise ratio (SNR) per bit when receiving noisy waveforms with SNR varying from -5 dB to 10 dB, thus significantly improving the bit-error-rate (BER).