Decimation Double-Phase Estimator: An Efficient and Unambiguous High-Order Binary Offset Carrier Tracking Algorithm

Traditional binary offset carrier (BOC) tracking algorithms process the upper and lower sideband signals together, and thus, the sampling frequency and computational requirements are much higher than that required for binary phase-shift keying tracking algorithms, especially for high-order BOC signals. Addressing existing limitations, this letter proposes a decimation double-phase estimator (DDPE) tracking algorithm for BOC signals. The algorithm uses a normal carrier and a subcarrier with a constant frequency to shift the upper and lower sideband signals of BOC to the zero frequency and decimates the signal before processing by the correlator. The residual carrier and the subcarrier are then tracked by the double-phase estimator algorithm. Decimating the signals significantly reduces the computational complexity, and for a BOC(6n, n) signal, the DDPE is found to reduce 86% of correlator operations with a signal-to-noise ratio loss of 0.5 dB.