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Multi-carrier transmission systems

  • US 6,865,232 B1
  • Filed: 07/15/1997
  • Issued: 03/08/2005
  • Est. Priority Date: 09/02/1996
  • Status: Expired due to Term
First Claim
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1. A multi-carrier transmission system comprising a first and a second transceiver, each of said transceivers having a receiver and a transmitter, wherein data is transmitted between said transceivers by modulating said data onto a multiplicity of carrier waves in the form of multi-bit symbols, wherein each carrier wave constitutes a channel, and wherein the number of bits per symbol, varies between channels and, within a channel, with time, so that each channel has associated therewith a bit loading parameter, characterized in that, in operation, said multi-carrier system is adapted to synchronously update, at said first and second transceivers, the bit loading parameters associated with each channel by transmission of data over a control channel, in that said control channel is established, at system start-up that includes activation of said multi-carrier system, on a predetermined one of said multiplicity of carrier waves whose identity is known to said first and second transceivers, said first and second transceivers for performing the followingbooting said transmitter and continuously transmitting frames in which all carrier waves other than said predetermined wave are modulated with random data, said transmitter also transmitting a system heartbeat, booting said receiver and initiating channel equalization, synchronizing clocks in said first and second transceivers, and establishing said control channel on said predetermined carrier wave on receipt of the system heartbeat, transferring said control channel to a carrier wave selected by said multi-carrier system and enabling bit loading control, and enabling all carrier waves, and in that said control channel is, after start-up, changed from said predetermined channel to a further channel, selected by said first transceiver on the basis of channel characteristics.

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