Patent ID: 9184964
Filing Date: 2015-11-10
Classification: H04L

Abstract:
1. A method of rapid non-data aided carrier signal acquisition for a low symbol rate carrier signal, the method comprising: receiving, by a receiver, an analog intermediate frequency carrier signal; converting the analog intermediate frequency carrier signal to a digital carrier signal using an analog-to-digital converter; down-converting the digital carrier signal to a frequency substantially at baseband using a digital quadrature tuner; reducing a sampling rate of the digital carrier signal using a decimation filter; determining a highest Fast Fourier Transform (FFT) based on a result of one or more FFT's generated by an FFT module using a peak finder; selecting an input source for the FFT module using a multiplexer; generating a frequency estimate of the digital carrier signal using a walking coarse detector (WCD); tuning a carrier recovery loop (CRL) based on the frequency estimate generated by the walking coarse detector; determining a final carrier frequency offset estimate using a result of the FFT module, a modulation removal, and the peak finder; programming an oscillator within the CRL to the final carrier frequency offset estimate using a processor such that carrier signal lock is achieved; correlating a received modulated carrier signal with a delayed version of the received modulated carrier signal using the walking coarse detector (WCD); and calculating a first frequency estimate of the digital carrier signal by the walking coarse detector (WCD) using an arctangent function and a multiplier of 4Rs/(2π) where Rs equals a symbol rate of the digital carrier signal.