Delay span classification for OFDM systems using selective filtering in the frequency domain

A receiving device, comprising:

• a receiving circuit configured to receive an orthogonal frequency-division multiplexing signal including a first multiplexing symbol comprising two first reference symbols in the frequency domain;
• and
• a control circuit configured to:
• receive the first multiplexing symbol from the receiving circuit;
• demodulate the first reference symbols of the first multiplexing symbol;
• determine a first autocorrelation value by autocorrelating the demodulated first reference symbols in the frequency domain;
• filter the orthogonal frequency-division multiplexing signal using a set of filters to provide a set of respective energy output values, the one or more parameters associated with the set of filters being calculated based upon the first autocorrelation value,
• wherein each filter from among the set of filters has a respective transfer width in terms of a different time length, each of the different time lengths being proportional to a length of time associated with the multiplexing signal;
• and
• determine the delay spread of the multiplexing signal as being within a transfer width associated with one of the filters from among the set of filters based on one or more energy output ratios exceeding one or more energy thresholds, the one or more energy output ratios being associated with ratios between one or more energy output values from among the set of respective energy output values.