Notifying bit allocation changes in a multicarrier modulation communications system
First Claim
1. A method of notifying a receiver of a bit allocation change in a multicarrier modulation communications system in which data frames and synchronization frames are transmitted in superframes from a transmitter to the receiver, comprising the steps of:
- at the transmitter, changing an inversion state of successive synchronization frames to notify the receiver of a bit allocation change; and
at the receiver, detecting a change in inversion state of received synchronization frames to determine the bit allocation change.
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Accused Products
Abstract
In a multicarrier modulation communications system, a change of a bit allocation table for the multiple subchannels or tones is notified from a transmitter to a receiver by a change in the inversion state of synchronization symbols provided in superframes of transmitted multicarrier symbols, successive changes of the bit allocation table being indicated by opposite changes of the inversion state of the synchronization symbols, respectively from non-inverted to inverted synchronization symbols and from inverted to non-inverted synchronization symbols. This provides resistance to errors and facilitates rapid recovery in the event that errors occur. A superframe number can also be used to identify when the inversion state of the synchronization symbols is to be changed.
42 Citations
14 Claims
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1. A method of notifying a receiver of a bit allocation change in a multicarrier modulation communications system in which data frames and synchronization frames are transmitted in superframes from a transmitter to the receiver, comprising the steps of:
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at the transmitter, changing an inversion state of successive synchronization frames to notify the receiver of a bit allocation change; and
at the receiver, detecting a change in inversion state of received synchronization frames to determine the bit allocation change. - View Dependent Claims (2, 3)
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4. A method of notifying a receiver of bit allocation changes in a DMT (discrete multitone) communications system in which information is transmitted from a transmitter to the receiver in superframes each of which comprises a plurality of DMT data symbols and a synchronization symbol, comprising the steps of:
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at the transmitter, changing an inversion state of synchronization symbols in successive superframes, from non-inverted to inverted and from inverted to non-inverted, to notify the receiver of successive bit allocation changes; and
at the receiver, detecting changes in the inversion state of received synchronization symbols in successive superframes, from non-inverted to inverted and from inverted to non-inverted, to determine the successive bit allocation changes. - View Dependent Claims (5, 6, 7, 8)
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9. A method of effecting bit allocation changes in a DMT (discrete multitone) communications system in which information is transmitted from a transmitter to a receiver in superframes each of which comprises a plurality of DMT data symbols and a synchronization symbol, comprising the steps of:
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at the transmitter, in response to a request from the receiver for a change of bit allocations, sending to the receiver an acknowledgement identifying a superframe and, commencing with the identified superframe, changing an inversion state of synchronization symbols in successive superframes, from non-inverted to inverted or from inverted to non- inverted, and implementing said bit allocation changes; and
at the receiver, sending said request for a change in bit allocations, detecting the acknowledgement and identified superframe, and detecting the change in the inversion state of received synchronization symbols in successive superframes and implementing said bit allocation changes commencing with the identified superframe. - View Dependent Claims (10, 11, 12, 13, 14)
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Specification