Broadcom Corporation

Arthur J Carlson

Gottfried Ungerboeck

Haixiang Liang

In a communication system, Huffman coding techniques are used to obtain shaping gains for an improvement in data transmission rates. More particularly, a novel method of Huffman shaping is described that achieves a shaping gain of greater than 1 dB. The shaping gain results in a higher data rate transmission in a communication system where transmitted power is constrained.

System and method for Huffman shaping in a data communication system

In a data communication system, a transmitter of an ADSL modem uses a PRBS generator to generate a plurality of ADSL signals. The transmitter computes the Peak to Average (e.g., root-mean-square) ('PAR') ratio of each of the ADSL signals generated. The ADSL signal having the lowest PAR is determined, and the corresponding state of the PRBS generator is noted. The signal having the lowest PAR, or at least the corresponding state of the PRBS generator, is then used to generate a Q-mode signal.

System and method for rapid generation of low PAR Q-mode signals

System and method for huffman shaping in a data communication system

In a data communication system, a transmitter of a modem, for example, uses a single scrambler to operate in a data communication mode and in a non-data mode. During the data communication mode the scrambler is used to scramble data for communication by the transmitter. During the non-data mode, the scrambler is used to generate a non-data mode signal for communication by the scrambler. The modem may be an ADSL modem, for example, in which case the data communication mode is SHOWTIME while the non-data mode may be Q-mode.

Data scrambler generation of pseudo-random bit sequence for semi-stationary Q-mode signal

The present invention relates to a system and method for selecting one of plurality of PRBS generators for use with a modem. The modem includes a measuring device adapted to measure an operating environment of the modem; and a storage device adapted to store a list of PRBS generator definitions. The modem selects one of a plurality of PRBS generators based on the measurement of the operating environment.

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Nevada City, CA, United States of America

Arthur J Carlson