A method for extracting a parameter of a communication channel from a channel estimate that characterizes the communication channel in terms of a frequency response over time. The method includes generating a set of feature identifiers that characterize features of the channel, for example energy peaks or troughs and determining the parameter, for example time delay of a multipath signal or frequency offset of a multipath signal, dependent on the feature identifiers. Methods using the parameter are also described including methods to estimate the environment.