A bidirectional communication system is provided. In one embodiment, a system comprises a host; and a plurality of remote units, wherein a plurality of tones is shared among the plurality of remote units in order to communicate with the host using orthogonal frequency division multiplexing, wherein the...http://www.google.fr/patents/US7352779?utm_source=gb-gplus-shareBrevet US7352779 - System for multi-frame alignment
