Memory-efficient ADSL transmission in the presence of TCM-ISDN interferers
AssigneeTexas Instruments Incorporated
InventorsKonrad W. Kratochwil, Thomas N. Zogakis, Peter J. Melsa
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Abstract
A method of communicating data across a channel that experiences near-end cross talk (NEXT) interference and far-end cross talk (FEXT) interference in alternate intervals. In one embodiment, the method comprises: a) determining NF, the number of bits per symbol usable in a FEXT-only mode of operation; b) determining NS, a number of bits per symbol usable in a single mode of operation; c) determining whether the FEXT-only mode or the single mode provides a higher data rate; and d) configuring a modem to transmit using the mode having a higher data rate. The FEXT-only mode may be determined to have a higher data rate when 126NF>340NS.
Claims23
A method of communicating data across a channel that experiences near-end cross talk (NEXT) interference and far-end cross talk (FEXT) interference in alternate intervals, the method comprising:
- determining NF, a number of bits per symbol usable in a FEXT-only mode of operation;
- determining NS, a number of bits per symbol usable in a single mode of operation;
- determining NF-LO, a number of bits per FEXT symbol usable in a reduced-carrier-number mode;
- determining NN-LO, a number of bits per NEXT symbol usable in the reduced-carrier number mode;
- combining NF-LO and NN-LO to determine whether a dual mode of operation in the reduced-carrier number mode provides a higher data rate than the data rates available in the FEXT-only mode and single mode;
- and
- configuring a modem to transmit using the mode having a highest data rate.
A method of communicating data between a first modem and a second modem via a channel that experiences near-end cross talk (NEXT) interference and far-end cross talk (FEXT) interference in alternate intervals, the method comprising:
- said first modem determining a first preferred communication mode from a mode set, wherein the mode set consists of single mode, FEXT-only mode, and reduced-carrier-number dual mode;
- said second modem determining a second preferred communication mode from said mode set;
- said first modem transmitting data using said second preferred communication mode;
- and
- said second modem transmitting data using said first preferred communication mode.
A modem that comprises:
- a processor configured to couple to a channel to transmit and receive data via the channel, wherein the channel experiences alternate intervals of near-end cross talk (NEXT) and far-end cross talk (FEXT);
- and
- a memory coupled to the processor, and configured to store a single bit table;
- wherein the processor determines a communication mode from a mode set consisting of single mode, FEXT-only mode, and reduced-carrier-number dual mode, and further determines a number of bits per symbol usable in each mode of the mode set,
- wherein the processor determines which of the modes is a higher data rate mode, and
- wherein the processor stores the bit table for the higher data rate mode in the memory.
Dependencies are inferred from the claim text.