Channel quality indicator for wireline channel degradation detection

• US 9,882,747 B2
• Filed: 12/15/2016
• Issued: 01/30/2018
• Est. Priority Date: 12/16/2015
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: Marvell World Trade Limited (Marvell Technology Group Limited)
• Inventors: Dai, Shaoan, Gu, Zhenzhong, Cheong, Kok-Wui
• Primary Examiner(s): Tran, Khanh C
• Application Number:
  US15/380,965
• Publication Number:
  US 20170180161A1
• Time in Patent Office: 411 Days
• CPC Class Codes: H04B 17/309 Measuring or estimating channel quality parameters
• CPC Class Codes: H04B 3/23 using a replica of transmitted signal in the time domain, e.g. echo cancellers
• CPC Class Codes: H04B 3/235 combined with adaptive equaliser
• CPC Class Codes: H04B 3/237 using two adaptive filters, e.g. for near end and for end echo cancelling
• CPC Class Codes: H04B 3/493 Testing echo effects or singing
• CPC Class Codes: H04L 2025/03802 Signalling on the reverse channel
• CPC Class Codes: H04L 25/03057 with a recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 25/03146 with a recursive structure H04L25/03127 takes precedence
• CPC Class Codes: H04L 25/03885 adaptive

Abstract

Systems and techniques relating to channel degradation detection for communication systems are described. A described system includes an interface to transmit signals and receive signals via a channel that includes a cable; an echo canceller coupled with the interface, the echo canceller to perform echo cancellation based on echo tap values to remove portions of the transmitted signals that appear as echoes within the received signals; an equalizer coupled with the interface, the equalizer to perform signal equalization based on equalizer tap values, the equalizer tap values being determined based on at least a portion of the received signals to adjust an impulse response of the channel and reduce inter-symbol interference within the received signals; and circuitry configured to determine a return loss channel quality indicator of the channel based on the echo tap values, determine an insertion loss channel quality indicator of the channel based on the equalizer tap values, or both.

Claims

1. An apparatus comprising:

an interface to transmit signals and receive signals via a channel that includes a cable;

an echo canceller coupled with the interface, the echo canceller to perform echo cancellation based on echo tap values to remove portions of the transmitted signals that appear as echoes within the received signals;

an equalizer coupled with the interface, the equalizer to perform signal equalization based on equalizer tap values, the equalizer tap values being determined based on at least a portion of the received signals to adjust an impulse response of the channel and reduce inter-symbol interference within the received signals; and

circuitry configured to determine a return loss channel quality indicator of the channel based on the echo tap values, determine an insertion loss channel quality indicator of the channel based on the equalizer tap values, or both, and wherein the circuitry is configured to generate a warning indication based on the return loss channel quality indicator or the insertion loss channel quality indicator exceeding a threshold, the warning indication indicating a degradation of the cable or the channel.

2. The apparatus of claim 1, wherein the circuitry is configured to determine the return loss channel quality indicator based on a summation of squared versions of the echo tap values.

3. The apparatus of claim 1, wherein the circuitry is configured to determine the return loss channel quality indicator based on a summation of absolute value versions of the echo tap values.

4. The apparatus of claim 1, wherein the circuitry is configured to determine the insertion loss channel quality indicator based on a summation of squared versions of the equalizer tap values.

5. The apparatus of claim 1, wherein the circuitry is configured to determine the insertion loss channel quality indicator based on a summation of absolute value versions of the equalizer tap values.

6. The apparatus of claim 1, wherein the equalizer comprises a feedforward equalizer (FFE) and a decision-feedback equalizer (DFE), wherein the circuitry is configured to adjust channel compensation from the FFE before a determination of the insertion loss channel quality indicator, and wherein the insertion loss channel quality indicator is based on a main tap value associated with the DFE and a channel gain value.

7. The apparatus of claim 1, wherein the return loss channel quality indicator is mapped to a k-bit value, and wherein the insertion loss channel quality indicator is mapped to a k-bit value.

8. A method, comprising:

transmitting signals via a channel that includes a cable;

receiving signals via the channel;

performing echo cancellation based on echo tap values to remove portions of the transmitted signals that appear as echoes within the received signals;

determining equalizer tap values based on at least a portion of the received signals to adjust an impulse response of the channel and reduce inter-symbol interference within the received signals;

performing signal equalization based on the equalizer tap values;

determining a channel quality indicator of the channel, wherein determining the channel quality indicator comprises determining a return loss channel quality indicator of the channel based on the echo tap values, determining an insertion loss channel quality indicator of the channel based on the equalizer tap values, or both; and

providing the channel quality indicator to an on-board diagnostic system to detect a degradation of the cable or the channel over time.

9. The method of claim 8, comprising:

generating a warning indication based on the return loss channel quality indicator or the insertion loss channel quality indicator exceeding a threshold, the warning indication indicating a degradation of the cable or the channel.

10. The method of claim 8, comprising:

determining the return loss channel quality indicator based on a summation of squared versions of the echo tap values.

11. The method of claim 8, comprising:

determining the return loss channel quality indicator based on a summation of absolute value versions of the echo tap values.

12. The method of claim 8, comprising:

determining the insertion loss channel quality indicator based on a summation of squared versions of the equalizer tap values.

13. The method of claim 8, comprising:

determining the insertion loss channel quality indicator based on a summation of absolute value versions of the equalizer tap values.

14. The method of claim 8, wherein performing the signal equalization comprises using a feedforward equalizer (FFE) and a decision-feedback equalizer (DFE), wherein the method further comprises adjusting channel compensation from the FFE before a determination of the insertion loss channel quality indicator, and wherein the insertion loss channel quality indicator is based on a main tap value associated with the DFE and a channel gain value.

15. The method of claim 8, wherein the return loss channel quality indicator is mapped to a k-bit value, and wherein the insertion loss channel quality indicator is mapped to a k-bit value.

16. A system comprising:

an on-board diagnostic system of a car;

a first device of the car; and

a second device of the car, wherein the second device is communicatively coupled with the first device via a channel that includes a cable that is subjected to an automotive environment of the car,

wherein the first device is configured to detect a degradation of the cable or the channel over time resulting from being subjected to the automotive environment of the car,

wherein the first device comprises (i) an interface to transmit signals and receive signals via the channel and (ii) a processor configured to perform echo cancellation based on echo tap values to remove portions of the transmitted signals that appear as echoes within the received signals, determine equalizer tap values based on at least a portion of the received signals to adjust an impulse response of the channel and reduce inter-symbol interference within the received signals, perform signal equalization based on the equalizer tap values, and determine a return loss channel quality indicator of the channel based on the echo tap values, determine an insertion loss channel quality indicator of the channel based on the equalizer tap values, or both, and

wherein the first device is configured to forward the return loss channel quality indicator to the on-board diagnostic system, forward the insertion loss channel quality indicator to the on-board diagnostic system, or both.

17. The system of claim 16, comprising:

circuitry to generate a warning indication based on the return loss channel quality indicator or the insertion loss channel quality indicator exceeding a threshold, the warning indication indicating a degradation of the cable or the channel.

18. The system of claim 16, wherein the processor is configured to determine the return loss channel quality indicator based on a summation of squared versions of the echo tap values or a summation of absolute value versions of the echo tap values.

19. The system of claim 16, wherein the processor is configured to determine the insertion loss channel quality indicator based on a summation of squared versions of the equalizer tap values or a summation of absolute value versions of the equalizer tap values.