A shuttle unit of the type comprising a discoid shuttle body provided with two conical portions, one front and one rear, disposed specularly with respect to the median plane of said shuttle body passing through the race of the shuttle body, and a shuttle driver guided in rotation to make the shuttle body oscillate. A particular method includes determining a data packet delivery rate between a first edge switch and a second edge switch coupled to a network. The pre-weighting may be achieved by \u201cinverting\u201d the selected channels so that the received SNRs are approximately similar for all selected channels.