High-speed receiver architecture

• US 8,831,074 B2
• Filed: 01/25/2011
• Issued: 09/09/2014
• Est. Priority Date: 10/03/2005
• Status: Active Grant

• Current Assignee: Marvell Asia Pte Limited (Marvell Technology Group Limited)
• Original Assignee: ClariPhy Communications Incorporated (Inphi Corporation)
• Inventors: Agazzi, Oscar E., Crivelli, Diego E., Carrer, Hugo S., Hueda, Mario R., Luna, German C., Grace, Carl
• Primary Examiner(s): Corrielus, Jean B
• Application Number:
  US13/013,149
• Publication Number:
  US 20110211842A1
• Time in Patent Office: 1,323 Days
• Field of Search: 375229-236, 375/259, 375/316, 375/324, 379/340, 379/398, 379/387.02, 324/607, 341126-128, 341/155, 341/156, 341/159, 333/18, 333/28.R, 708/300, 708/322, 708/323
• US Class Current: 375/219
• CPC Class Codes: H03M 13/41 using the Viterbi algorithm or Viterbi processors
• CPC Class Codes: H04B 1/38 Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
• CPC Class Codes: H04B 10/25073 using spectral equalisation, e.g. spectral filtering
• CPC Class Codes: H04B 10/2941 using an equalising unit, e.g. a filter H04B10/296 takes precedence
• CPC Class Codes: H04B 10/40 Transceivers
• CPC Class Codes: H04B 10/5059 using a feed-forward signal generated by analysing the optical or electrical input
• CPC Class Codes: H04B 10/6971 using equalisation
• CPC Class Codes: H04B 2001/0441 with linearisation using feed-forward
• CPC Class Codes: H04B 2201/709772 Joint detection using feedforward
• CPC Class Codes: H04B 3/235 combined with adaptive equaliser
• CPC Class Codes: H04B 7/005 Control of transmission; Equalising
• CPC Class Codes: H04B 7/0456 Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
• CPC Class Codes: H04L 2025/03477 not time-recursive
• CPC Class Codes: H04L 2025/03617 Time recursive algorithms H04L2025/03643 takes precedence
• CPC Class Codes: H04L 25/0202 Channel estimation
• CPC Class Codes: H04L 25/025 using least-mean-square [LMS] method
• CPC Class Codes: H04L 25/03038 with a non-recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 25/03057 with a recursive structure H04L25/03031 takes precedence
• CPC Class Codes: H04L 5/16 Half-duplex systems; Simplex/duplex switching; Transmission of break signals non-automatically inverting the direction of transmission

Abstract

A receiver (or transceiver) is selectable between a Gaussian mode and a non-Gaussian mode. In the non-Gaussian mode, a transformation block applies a non-linear transformation to signal samples to convert non-Gaussian noise in the signal samples to Gaussian or approximately Gaussian noise. In the Gaussian mode, the transformation block is bypassed. Samples are equalized using an equalizer configured to operate with a Gaussian or approximately Gaussian channel.

Claims

1. A transceiver for communication over a fiber, the transceiver comprising:

a host interface for receiving digital data, the received digital data in a host format;

a laser driver port for generating an electrical signal modulated by the received digital data in electrical form, the electrical signal suitable for driving a laser driver;

transmit path circuitry coupled between the host interface and the laser driver port; and

receive path circuitry to receive an electrical signal representing an optical signal received from the fiber, and to provide the received electrical signal to the host interface, the receive path circuitry comprising;

an analog-to-digital converter that generates signal samples from the received electrical signal;

a transformation block applying a nonlinear transformation to the signal samples to generate transformed samples, wherein the nonlinear transformation converts non-Gaussian noise in the signal samples to Gaussian or approximately Gaussian noise;

a multiplexer to select between a first input and a second input depending on a mode of the receive path circuitry selectable between a Gaussian mode and a non-Gaussian mode, the first input coupled to receive untransformed samples from the analog-to-digital converter, the second input coupled to receive the transformed samples from the transformation block, the multiplexer selecting the first input when operating in the Gaussian mode, and the multiplexer selecting the second input when operating in the non-Gaussian mode;

an equalizer configured to equalize the selected samples from the multiplexer, the equalizer configured to operate on a Gaussian or approximately Gaussian channel.

2. The transceiver of claim 1, wherein the multiplexer selects the first input to operate the receive path circuitry in a Gaussian mode responsive to the fiber having predominantly Gaussian noise.

3. The transceiver of claim 1, wherein the multiplexer selects the second input to operate the receive path circuitry in a non-Gaussian mode responsive to the fiber having predominantly non-Gaussian noise.

4. The transceiver of claim 3, wherein the predominantly non-Gaussian noise comprises amplified spontaneous emission (ASE) noise.

5. The transceiver of claim 1, wherein the transformation block implements the function LUT(y_n)=sqrt(y_n+y_ref) for a sample y_n when the sample y_n is in an interval between −

y_ref and +y_ref and wherein y_ref comprises a reference value.

6. The transceiver of claim 1, wherein the transformation block implements the function

7. A receiver comprising:

an analog-to-digital converter that generates signal samples from a received signal;

a transformation block applying a nonlinear transformation to the signal samples to generate transformed samples, wherein the nonlinear transformation converts non-Gaussian noise in the signal samples to Gaussian or approximately Gaussian noise;

a multiplexer to select between a first input and a second input depending on a mode of the receiver selectable between a Gaussian mode and a non-Gaussian mode, the first input coupled to receive untransformed samples from the analog-to-digital converter, the second input coupled to receive the transformed samples from the transformation block, the multiplexer selecting the first input when operating in the Gaussian mode, and the multiplexer selecting the second input when operating in the non-Gaussian mode;

an equalizer configured to equalize the selected samples from the multiplexer, the equalizer configured to operate on a Gaussian or approximately Gaussian channel.

8. The receiver of claim 7, wherein the multiplexer selects the first input to operate the receiver in the Gaussian mode responsive to the receiver being coupled to a fiber having predominantly Gaussian noise.

9. The receiver of claim 7, wherein the multiplexer selects the second input to operate the receiver in the non-Gaussian mode responsive to the receiver being coupled to a fiber having predominantly non-Gaussian noise.

10. The receiver of claim 9, wherein the predominantly non-Gaussian noise comprises amplified spontaneous emission (ASE) noise.

11. The receiver of claim 7, wherein the transformation block implements the function LUT(y_n)=sqrt(y_n+y_ref) for a sample y_n when the sample y_n is in an interval between −

y_ref and +y_ref and wherein y_ref comprises a reference value.

12. The receiver of claim 7, wherein the transformation block implements the function

13. A method for equalizing samples in the presence of noise, the method comprising:

generating, by an analog-to-digital converter, signal samples from a received signal;

applying, by a signal processor, a nonlinear transformation to the signal samples to generate transformed samples, wherein the nonlinear transformation converts noise in the signal samples to Gaussian or approximately Gaussian noise;

selecting between a first input and a second input of a multiplexer of the signal processor depending on a mode of the signal processor selectable between a Gaussian mode and a non-Gaussian mode, the first input coupled to receive untransformed samples from the analog-to-digital converter, the second input coupled to receive the transformed samples from the signal processor, the multiplexer selecting the first input when the signal processor is operating in the Gaussian mode, and the multiplexer selecting the second input when the signal processor is operating in the non-Gaussian mode;

equalizing the selected samples from the multiplexer using an equalizer of the signal processor configured to operate on a Gaussian or approximately Gaussian channel.

14. The method of claim 13, wherein the multiplexer selects the first input to operate the equalizer in a Gaussian mode responsive to the equalizer being coupled to a fiber having predominantly Gaussian noise.

15. The method of claim 13, wherein the multiplexer selects the second input to operate the signal processor in a non-Gaussian mode responsive to the signal samples originating from a fiber having predominantly non-Gaussian noise.

16. The method of claim 15, wherein the predominantly non-Gaussian noise comprises amplified spontaneous emission (ASE) noise.

17. The method of claim 13, wherein applying the non-linear transformation comprises implementing the function LUT(y_n)=sqrt(y_n+y_ref) for a sample y_n when the sample y_n is in an interval between −

y_ref and +y_ref and wherein y_ref comprises a reference value.

18. The method of claim 13, wherein the applying the non-linear transformation comprises implementing the function: