An Iterative Array Signal Segregation Algorithm: A method for interference cancelation and multipath mitigation in complex environments

A frequency-domain array signal segregation using an iterative approach (ASSIA) is developed to estimate the directions of arrival (DoAs), magnitudes, and phases of the signals' spectral components in a multipath environment. This is accomplished by using a uniform circular antenna array whose elements are individually connected to the radiofrequency (RF) front end of a neoteric radio. This technique is utilized to spatially and spectrally separate the communication signals of interest from the strong interfering signals without a priori knowledge regarding their DoAs. Through an extensive comparison with the other techniques reported in the literature, it is shown that ASSIA can detect the DoAs and signal levels of wide dynamic range (DR) much more accurately than what can be done with the existing techniques, provided that the signals' angular spacing is larger than the array beamwidth. Array calibration to capture the fabrication errors is essential to achieve the high level of the DR of signals that ASSIA can handle. The performance of the algorithm in the presence of strong jammers in complex multipath environments with Rayleigh fading characteristics is examined using numerical simulations based on an accurate ray-tracing propagation model. A statistical analysis based on Monte Carlo simulations shows that in such an environment, an ASSIA radio with a 12-element uniform circular array can improve the signal-to-jammer ratio (SJR) from -20 to at least +2 dB (minimum of 22-dB improvement) in more than 70% of occasions.