Adapting communication link parameters using signal-to-noise (SNR) deviation metrics

1 . A communication system comprising:

a receiver circuit;

a Forward Error Correction (FEC) circuit operatively coupled to the receiver circuit; and

a controller operatively coupled to the receiver circuit and the FEC circuit, wherein the controller is to:

receive equalized error data from the receiver circuit;

determine, using the equalized error data and a nominal signal power, a signal-to-noise ratio (SNR) deviation metric, the SNR deviation metric being indicative of an estimated post-FEC bit error rate (BER) of the FEC circuit; and

adjust, based on the SNR deviation metric, at least one of a FEC parameter of the FEC circuit or a link parameter of the receiver circuit.

2 . The communication system of claim 1 , wherein the equalized error data comprises at least one of a received error signal, a received detected equalized error signal, or individual SNR measurements determined by the receiver circuit.

3 . The communication system of claim 2 , wherein, to determine the SNR deviation metric, the controller is to determine a measured SNR histogram using the at least one of the received error signal, the received detected equalized error signal, or the SNR measurements over a window of time, L.

4 . The communication system of claim 3 , wherein L corresponds to a FEC codeword size used by the FEC circuit.

5 . The communication system of claim 3 , wherein, to determine the measured SNR histogram, the controller is to determine a statistical variance or a standard deviation of the received error signal or the received detected equalized error signal.

6 . The communication system of claim 1 , wherein the SNR deviation metric is based on an SNR histogram difference metric derived from a comparison of a measured SNR histogram and a target SNR histogram.

7 . The communication system of claim 6 , wherein the controller is to determine the SNR histogram difference metric by:

determining an individual difference metric representing an absolute value of a deviation of the measured SNR histogram from the target SNR histogram at each value of the measured SNR histogram; and

determining the SNR histogram difference metric by summing the individual difference metrics.

8 . The communication system of claim 1 , wherein the SNR deviation metric is based on an SNR histogram difference metric derived from a comparison of a measured SNR histogram and a target SNR histogram.

9 . The communication system of claim 1 , wherein:

the FEC circuit comprises:

an interleaver; and

a decoder;

the FEC parameter is an interleave factor of the interleaver; and

the controller, to adjust at least one of the FEC parameter or the link parameter, is to change the interleave factor from a first value to a second value.

10 . The communication system of claim 1 , wherein the receiver circuit comprises a Serializer/Deserializer (SerDes) circuit, wherein:

the link parameter is a SerDes parameter of the SerDes circuit; and

the controller, to adjust at least one of the FEC parameter or the link parameter, is to change the SerDes parameter from a first value to a second value.

11 . The communication system of claim 1 , wherein the receiver circuit comprises a Serializer/Deserializer (SerDes) circuit, wherein:

the FEC circuit comprises an interleaver;

the FEC parameter is an interleave factor of the interleaver;

the link parameter is a SerDes parameter of the SerDes circuit; and

the controller, to adjust at least one of the FEC parameter or the link parameter, is to:

change the interleave factor from a first value to a second value; and

change the SerDes parameter from a third value to a fourth value.

12 . The communication system of claim 1 , further comprising:

a receiver comprising the receiver circuit, the FEC circuit, and the controller; and

a transmitter comprising a second FEC circuit, wherein the controller is further to send an indication to the second FEC circuit, the indication to adjust an FEC parameter of the second FEC circuit.

13 . The communication system of claim 1 , wherein:

the FEC circuit comprises:

a first interleaver;

a first decoder;

a second interleaver; and

a second decoder;

the FEC parameter is a first interleave factor of the first interleaver and the second interleaver comprises a second interleave factor; and

the controller, to adjust at least one of the FEC parameter or the link parameter, is to:

change the first interleave factor from a first value to a second value; and

change the second interleave factor from a third value to a fourth value.

14 . A method comprising:

receiving equalized error data from a receiver circuit;

determining, using the equalized error data and a nominal signal power, a signal-to-noise ratio (SNR) deviation metric, the SNR deviation metric being indicative of a post-Forward Error Correction (FEC) bit error rate (BER) of an FEC system coupled to the receiver circuit; and

adjusting, based on the SNR deviation metric, at least one of an FEC parameter of the FEC system or a link parameter of the receiver circuit to reduce the post-FEC BER of the FEC system.

15 . The method of claim 14 , wherein the equalized error data comprises at least one of a received error signal, a received detected equalized error signal, or individual SNR measurements determined by the receiver circuit, and wherein determining the SNR deviation metric comprises determining a measured SNR histogram using the at least one of the received error signal, the received detected equalized error signal, or the SNR measurements over a window of time, L, and wherein L corresponds to a FEC codeword size used by the FEC system.

16 . The method of claim 15 , wherein determining the measured SNR histogram comprises determining a statistical variance or a standard deviation of the received error signal or the received detected equalized error signal.

17 . The method of claim 14 , wherein determining the SNR deviation metric comprises determining an SNR histogram difference metric by comparing a measured SNR histogram and a target SNR histogram.

18 . The method of claim 17 , wherein determining the SNR histogram difference metric comprises:

determining an individual difference metric representing an absolute value of a deviation of the measured SNR histogram from the target SNR histogram at each value of the measured SNR histogram; and

determining the SNR histogram difference metric by summing the individual difference metrics.

19 . The method of claim 14 , wherein adjusting at least one of the FEC parameter or the link parameter comprises changing an interleave factor of an interleaver of the FEC system from a first value to a second value.

20 . The method of claim 14 , wherein adjusting at least one of the FEC parameter or the link parameter comprises:

changing a first interleave factor of a first interleaver of the FEC system from a first value to a second value; and

changing a second interleave factor of a second interleaver of the FEC system from a third value to a fourth value.

21 . The method of claim 14 , wherein the receiver circuit is a Serializer/Deserializer (SerDes) circuit, wherein adjusting at least one of the FEC parameter or the link parameter comprises changing a SerDes parameter of the SerDes circuit from a first value to a second value.

22 . The method of claim 14 , wherein the receiver circuit is a Serializer/Deserializer (SerDes) circuit, wherein adjusting at least one of the FEC parameter or the link parameter comprises:

changing an interleave factor of an interleaver of the FEC system from a first value to a second value; and

changing a SerDes parameter of the SerDes circuit from a third value to a fourth value.

23 . A communication system comprising:

a Serializer/Deserializer (SerDes) circuit coupled to a communication channel;

a Forward Error Correction (FEC) system operatively coupled to the SerDes circuit; and

a controller operatively coupled to the SerDes circuit and the FEC system, wherein the controller is to:

receive equalized error data from the SerDes circuit;

determine, using the equalized error data and a nominal signal power, a signal-to-noise ratio (SNR) deviation metric, the SNR deviation metric being indicative of an estimated post-FEC bit error rate (BER) of the FEC system; and

change, based on the SNR deviation metric, one or more parameters of the FEC system or the SerDes circuit.

24 . The communication system of claim 23 , wherein the equalized error data comprises at least one of a received error signal, a received detected equalized error signal, or individual SNR measurements determined by the SerDes circuit.

25 . The communication system of claim 24 , wherein, to determine the SNR deviation metric, the controller is to determine a measured SNR histogram using the at least one of the received error signal, the received detected equalized error signal, or the SNR measurements over a window of time, L, wherein L corresponds to a FEC codeword size used by the FEC system.

26 . The communication system of claim 23 , wherein the SNR deviation metric is based on an SNR histogram difference metric derived from a comparison of a measured SNR histogram and a target SNR histogram.

27 . The communication system of claim 26 , wherein the controller is to determine the SNR histogram difference metric by:

determining an individual difference metric representing an absolute value of a deviation of the measured SNR histogram from the target SNR histogram at each value of the measured SNR histogram; and

determining the SNR histogram difference metric by summing the individual difference metrics.

28 . The communication system of claim 23 , wherein:

the FEC system comprises:

an interleaver; and

a decoder;

the one or more parameters comprise an interleave factor of the interleaver; and

the controller, to change the one or more parameters of the FEC system or the SerDes circuit, is to change the interleave factor from a first value to a second value.

29 . The communication system of claim 23 , wherein the FEC system comprises:

a first interleaver;

a first decoder;

a second interleaver; and

a second decoder;

wherein the one or more parameters comprise a first interleave factor of the first interleaver and a second interleave factor of the second interleaver and

wherein the controller, to change the one or more parameters of the FEC system or the SerDes circuit, is to:

change the first interleave factor from a first value to a second value; and

change the second interleave factor from a third value to a fourth value.