A communication circuit arrangement includes a sub sampling circuit configured to obtain wideband signal data including candidate reference sequences from a plurality of carrier channels and to downsample the wideband signal data to shift the candidate reference sequences closer to each other in frequency, a comparison circuit configured to compare the downsampled signal data to a composite detection sequence to detect whether any of the candidate reference sequences match any of a plurality of predefined reference sequences in the composite detection sequence, and a decision circuit configured to determine whether any of the plurality of carrier channels contain an active network based on the detection results.