Spectrally efficient maximum-likelihood detection for chaotic underdetermined MIMO systems

In this paper, we present a technique that provides spatial diversity for a Chaos Shift Keying (CSK) transceiver. The system transmits and receives chaos-based modulated signals through multiple antennas with high spectral efficiency. We show that Multiple-Input Multiple-Output (MIMO) systems greatly improve the Bit-error-rate (BER) performance of chaotic communications over the Rayleigh channel. The robustness of the method proposed herein supports signal detection over Virtual MIMO systems (N <; M). Furthermore, we discuss the performance of our proposed ML chaotic detector when perfect CSI is not available at the receiver side. A joint channel estimation and signal detection method is adapted based on the received signal subspace analysis made by which uses statistics from the entire transmitted data frame.