System and method for providing crosstalk management for high-speed signaling links
The present invention relates in general to a method, apparatus, and article of manufacture for providing high-speed digital communications through a communications channel. In one aspect, the present invention employs crosstalk management techniques and structures that increase the system performance in channel communications.
1. A communications system for minimizing crosstalk in high speed signaling links within a communications system, the communications system comprising:
a plurality of transmitters, each transmitter including transmit signal level adjustment circuitry to adjustable transmit signal level of the transmitter; and
a plurality of receivers, each receiver includes circuitry to sense a received signal level and, in response thereto, generate a control signal, wherein each receiver is coupled to an associated transmitter;
wherein each transmitter, in response to the control signal from the associated receiver, adjusts the transmit signal level to cause a received level sensing signal to correspond to a desired received signal level;
wherein each receiver is configured to generate a sum data value of the sign of an error value times the sign of data values over a sequence of data symbols received by the receiver; and
wherein the control signal is configured to command an associated transmitter to adjust the signal level based upon the sign of the sum data value generated in the receiver.
2. The communications system according to claim 1 , wherein the plurality of transmitters and receivers are integrated into transceivers.
3. The method according to claim 1 , wherein the desired received signal level is substantially the same for all of the receivers, which forces crosstalk-related signal-to-noise-ratios (SNR) to be substantially equal for all the receivers.
4. The communications system according to claim 2 , wherein the desired received signal level is adjustable.
5. The communications system according to claim 2 , wherein the high speed signaling links includes a backplane.
6. The communications system according to claim 1 , wherein the received level sensing signal is transmitted to the associated transmitter via an external interface.
7. The communications system according to claim 6 , wherein the desired received signal level is the same for all the receivers.
8. The communications system according to claim 6 , wherein the desired received signal level is adjustable.
9. The communications system according to claim 6 , wherein the high speed signaling links includes a backplane.
10. A method for providing crosstalk management for high speed signaling links within a communications channel, the communications channel having a plurality of near-end transmitters and far-end receivers, wherein each transmitter is associated with a particular receiver, the method comprising:
transmitting a plurality of signals between the near-end transmitters and the far-end receiver, the plurality of transmitters having an adjustable transmit signal level; and
receiving the plurality of signals at the corresponding plurality of receivers, each of the receiver having circuitry to sense a receive level;
wherein each receive level is utilized by each of the plurality of transmitters to set the adjustable transmit signal levels to cause the receive level to correspond to a desired receive signal level;
generating a sum data value of the sign of an error value times the sign of data values over a sequence of data symbols received by a far-end receiver and
commanding the near-end transmitter to adjust the signal level based upon the sum data value generated in the far-end receiver.
11. The method according to claim 10 , wherein commanding the near-end transmitter to adjust the signal level output based upon the sum data value involves:
commanding the near-end transmitter to increase the signal level if the sign of the sum data value is negative; and
commanding the near-end transmitter to decrease the signal level if the sign of the sum data value is positive.
12. The method according to claim 10 , wherein the transmitter is integrated into a transceiver.
13. The method according to claim 10 , wherein the receive level sensing signal is transmitted from the far-end receiver to the corresponding near-end transmitter via an external interface.
14. The method according to claim 13 , wherein the desired received signal level is the same for all the receivers.
15. The method according to claim 13 , wherein the desired received signal level is adjustable.
16. The method according to claim 10 , wherein the desired received signal level is substantially the same for all of the receivers, which forces crosstalk-related signal-to-noise-ratios (SNR) to be substantially equal for all the receivers.