Low-Complexity Real-Time Single-Tone Phase and Frequency Estimation

This paper presents a low-complexity real-time single-tone phase and frequency estimation technique based on zero-crossing detection and linear regression. The proposed zerocrossing phase and frequency estimator fills a gap between lowcomplexity phase locked loop estimation and high-performance maximum likelihood estimation. Similar to a phase locked loop, the zero-crossing phase and frequency estimator offers lowcomplexity sample-by-sample operation appropriate for real-time applications like distributed transmit beamforming. Numerical results demonstrate, however, that the proposed technique significantly exceeds the performance of phase locked loop estimation, closely tracking the Cramer-Rao lower bound over a wide range of signal to noise ratios.