Master/slave transceiver power back-off

1. A method of operation in an Ethernet transceiver, the method comprising:

in an initialization mode

transmitting signals to a link partner transceiver via a link;

applying an initial power back off parameter to the signals;

receiving a request from the link partner transceiver to adjust the initial power back off parameter, the request generated based on a detected signal power level of the signals as received by the link partner transceiver;

adjusting the initial power back off parameter to an adjusted value in response to the request;

setting the Ethernet transceiver power back off parameter to the adjusted value;

communicating the adjusted value to the link partner transceiver; and

in a normal operation mode

transmitting first data to the link partner transceiver using the adjusted value for the power back off parameter; and

receiving second data from the link partner transceiver, the second data having been transmitted with a power back off parameter that is constrained to be within a predefined range of the adjusted value.

2. The method according to claim 1 , wherein:

during the initialization mode

identifying the Ethernet transceiver as a master device; and

identifying the link partner transceiver as a slave device.

3. The method according to claim 1 , wherein a length of the link is not greater than 100 meters.

4. The method according to claim 3 , wherein the Ethernet transceiver is realized as a 10 GBASE-T transceiver.

5. The method according to claim 1 , further comprising:

iteratively performing the transmitting, receiving and adjusting until a threshold signal power level is detected, and a corresponding final value of the power back off parameter identified.

6. The method according to claim 5 , wherein the threshold signal power level is a minimum signal power based on a desired signal power versus crosstalk parameter.

7. The method according to claim 5 , wherein communicating the adjusted value includes the link parameter transceiver setting its power back off to within the predetermined range of the final value.

8. The method according to claim 1 , wherein the predefined range is less than 6 db.

9. A method of operation in an Ethernet transceiver, the method comprising:

receiving transmit signals from a link partner transceiver via a link with an applied initial power back off parameter;

detecting a signal power level associated with the received transmit signals;

generating a request to adjust the initial power back off parameter based on the detected signal power level;

transmitting the request to the link partner transceiver, the link partner transceiver to adjust the power back off parameter to an adjusted value in response to receiving the request;

receiving the adjusted value of the power back off parameter for the link partner transceiver;

setting the power back off parameter for the Ethernet transceiver within a predefined level of the adjusted value set by the link partner transceiver.

10. The method according to claim 9 , wherein:

the predefined range of values is less than 6 db within the final value.

11. The method according to claim 9 , wherein:

during an initialization mode

identifying the Ethernet transceiver as a slave device; and

identifying the link partner transceiver as a master device.

12. The method according to claim 9 , wherein:

detecting a signal power level includes determining the signal power of the received transmit signals using on-chip logic.

13. The method according to claim 9 , and further comprising:

iteratively performing the receiving, detecting, generating and transmitting until a threshold signal power level is reached, and a corresponding final value of the power back off parameter identified for the link partner transceiver.

14. The method according to claim 11 , wherein detecting a signal power level includes:

retrieving the threshold signal power level from a look-up table in the on-chip logic; and

comparing the detected signal power level to the threshold signal power level.

15. A method of setting power back off levels for first and second Ethernet transceivers coupled via an Ethernet link, the method comprising:

assigning an initial power back off to the first Ethernet transceiver;

transmitting signals from the first Ethernet transceiver to the second Ethernet transceiver,

the transmitted signals attenuated by an amount corresponding to the initial power back off;

receiving the transmitted signals at the second Ethernet transceiver;

detecting a signal power level associated with the received signals;

determining a signal power margin where the signal power may be reduced and still maintain acceptable signal quality;

if the signal power margin is above a threshold, transmitting a request from the second Ethernet transceiver to the first Ethernet transceiver, the request specifying an adjustment to the initial power back off;

setting the power back off for the first Ethernet transceiver to an adjusted value corresponding to the adjustment;

communicating the adjusted value of the power back off to the second Ethernet transceiver; and

setting the power back off for the second Ethernet transceiver to within a predetermined level of the adjusted value.

16. The method according to claim 15 , further comprising:

iteratively carrying out the transmitting, receiving, detecting, and determining until the detected signal power reaches a signal power threshold.

17. The method according to claim 15 , further comprising:

identifying the first Ethernet transceiver as a master device; and

identifying the second Ethernet transceiver as a slave device.

18. The method according to claim 15 , wherein a length of the Ethernet link is not greater than 100 meters.

19. The method according to claim 15 , wherein the first and second Ethernet transceivers are realized as 10 GBASE-T transceivers.

20. The method according to claim 15 , further comprising:

iteratively performing the transmitting, receiving and adjusting until a threshold signal power level is detected, and a corresponding final value of the power back off parameter identified.

21. The method according to claim 20 , wherein the threshold signal power level is a minimum signal power based on a desired signal power versus crosstalk parameter.