Early-Late Correlation for Wideband Interference AoA Estimation and Suppression in Analog Uniformly Spaced Linear TTD Arrays

Interference estimation and mitigation are of high importance in many applications of array signal processing. State-of-the-art angle and direction estimation techniques for digital arrays often rely on computationally-intensive complex algorithms. This paper introduces a novel delay measurement based low complexity Angle-of-Arrival (AoA) estimation method using analog True-Time-Delay (TTD) arrays for suppression of a single strong interference. The core of our method is the novel analog Early-Late Correlation (ELC) function that exhibits linear and odd properties enabling efficient time delay estimation with leading-lagging detections. Utilizing ELC time-delay measurements across different antenna elements in a linear TTD array, the AoA is estimated via a least-squares line-fitting solution. Interference suppression is achieved through destructive signal combining after applying proper delays in the analog domain. Simulations demonstrate the method's efficacy, achieving an interference suppression > 40dB for an OFDM interferer signal with Interference-to-Noise Ratio (INR) > -20dB and 100MHz BW in a 4-element linear TTD array.