Patent ID: 7486608

Claim:
A Digital Subscriber Line system comprising a transmitter for reusing bit allocations and gain factors for a normal data transmission mode in a low power mode, the transmitter comprising: a first memory for storing the bit allocations and gain factors for the normal data transmission mode and a bit allocation threshold value, T; a constellation mapper communicatively coupled to the memory, a data buffer and a pseudo random sequence generator, the mapper determining a number of bits to be retrieved for an ith sub-carrier, b i ′, in a low power mode based on a number of bits allocated, b i , for the ith sub-carrier in the normal transmission mode and the bit allocation threshold T; a transmitter control unit communicatively coupled to the constellation mapper and the memory, the control unit processing messages from a receiver, including messages related to mode operation; and a constellation encoder communicatively coupled to receive the determined number of bits for the ith sub-carrier from the mapper; and the system further comprising a receiver for reusing bit allocations and gain factors for the normal data transmission mode in a low power mode, the receiver comprising: a second memory for storing the bit allocations and the gain factors for the normal data transmission mode and the bit allocation threshold value, T; a constellation demapper communicatively coupled to the memory and communicatively coupled to receive a signal in an ith sub-carrier from the transmitter, the demapper determining the number of bits, b i ′, allocated by the transmitter for this ith sub-carrier, in the low power mode based on the number of bits allocated, b i , for the ith sub-carrier in the normal transmission mode and the bit allocation threshold T; a receiver control unit communicatively coupled to the constellation demapper and the memory, the control unit processing messages related to mode operation from the transmitter; and a constellation decoder communicatively coupled to receive an indicator of the determined number of bits allocated for the ith sub-carrier from the demapper.