Method and apparatus for generating a metric for use in one or more of lock detection, SNR estimation, and modulation classification

摘要

The present disclosure is directed at a method and apparatus for generating a metric for use in any one or more of lock detection, SNR estimation, and modulation classification. To generate the metric, an input angle in the form of a symbol phase or a difference in symbol phases is used to evaluate a base function. The base function relates possible metrics to possible input angles using a triangle wave having its maxima or minima at ideal input angles, and the other of its maxima or minima at angles midway the ideal input angles. Described are embodiments that are one or more of non-data aided; that may be implemented relatively efficiently in hardware; that can function using one sample/symbol; that can achieve relatively good detection certainty using relatively few estimates; and that can be used to implement modulation classifiers, lock detectors, and SNR estimators that are resilient to imperfections in automatic gain control.

主权项

1. A method for generating a metric for one or both of lock detection and signal-to-noise ratio (SNR) estimation, the method comprising:
obtaining a baseband symbol from a received carrier that is modulated using the symbol according to a modulation order (M) equaling the number of distinct ideal symbol phases used to modulate the received carrier; determining a received phase of the symbol; and generating the metric from the received phase, wherein possible metrics depend on possible received phases according to a base function that comprises a triangle wave having its maxima or minima located at ideal symbol phases and the other of its maxima or minima located at phases midway between adjacent ideal symbol phases.