Patent ID: 8665859

Claim:
An apparatus for synchronizing bidirectional communications in a multi-point digital communications system, the apparatus comprising: a transmitter configured, when the apparatus is operating according to a first communication mode, (i) to generate sub-symbols in a plurality of frequency bins using a first timing signal, at least one of the frequency bins having a first pilot tone sub-symbol, the first pilot tone sub-symbol having a frequency corresponding to the first timing signal, (ii) to combine the frequency bins and represent them in the form of a symbol, and (iii) to transmit the symbol over a transmission medium; and a receiver configured, when the apparatus is operating according to a second communication mode, to receive symbols including sub-symbols over a plurality of frequency bins, at least one of the frequency bins including a second pilot tone sub-symbol having a frequency corresponding to a second timing signal of a remote device, the receiver including a processor configured (i) to recover the second pilot tone sub-symbol using a third timing signal, (ii) to calculate a parameter value difference between the second pilot tone sub-symbol and a consecutive second pilot tone sub-symbol, and (iii) to cause a voltage controlled oscillator of the receiver to adjust the third timing signal based at least in part on the calculated parameter value difference.