Transmit adaptive equalization for communication system with one or more serial data channels

• US 20060050726A1
• Filed: 09/03/2004
• Published: 03/09/2006
• Est. Priority Date: 09/03/2004
• Status: Active Grant

• Current Assignee: Broadcom International Pte Ltd. (Broadcom, Inc.)
• Original Assignee: Agere Systems Incorporated (Broadcom, Inc.)
• Inventors: Smith, Lane A., Ahmed, Ali U., Brink, Robert D.
• Granted Patent: US 7,443,798 B2
• Time in Patent Office: Days
• US Class Current: 370/437
• CPC Class Codes: H04L 2025/03808 Transmission of equaliser coefficients
• CPC Class Codes: H04L 25/03133 with a non-recursive structure H04L25/03127 takes precedence

Abstract

In a communication system comprising first and second nodes, a transmit adaptive equalization technique is implemented. The first and second nodes may communicate over a Fibre Channel link or other medium. The first and second nodes comprise respective transmitter and receiver pairs, with the transmitter of the first node configured for communication with the receiver of the second node and the receiver of the first node configured for communication with the transmitter of the second node. The first node receiver is operative to receive from the second node transmitter, responsive to a signal transmitted by the first node transmitter to the second node receiver, information specifying an adjustment to one or more equalization parameters of the first node transmitter. The first node adjusts the equalization parameter(s) in accordance with the received information.

Claims

1. An apparatus for use in a communication system having a plurality of nodes, the apparatus comprising:

a first node, the first node comprising a transmitter configured for communication with a receiver of a second node and a receiver configured for communication with a transmitter of the second node;

the first node being operative;

(i) to receive in the receiver of the first node from the transmitter of the second node, responsive to a signal transmitted by the transmitter of the first node to the receiver of the second node, information specifying an adjustment to one or more equalization parameters of the transmitter of the first node, and (ii) to adjust the one or more equalization parameters in accordance with the received information.

2. The apparatus of claim 1 wherein the first node is coupled to the second node via a bidirectional serial data channel.

3. The apparatus of claim 1 wherein the first node is configured to communicate with the second node over a Fibre Channel link.

4. The apparatus of claim 1 wherein the second node evaluates signal quality of the signal transmitted by the transmitter of the first node, and determines the information specifying the adjustment to the one or more equalization parameters based on the signal quality evaluation.

5. The apparatus of claim 1 wherein the process of transmitting a signal and receiving information specifying an adjustment to one or more equalization parameters is repeated until signal quality of a given transmitted signal as received at the second node is determined to meet one or more designated criteria.

6. The apparatus of claim 1 wherein the one or more equalization parameters comprise a plurality of tap coefficients of a filter associated with the transmitter of the first node.

7. The apparatus of claim 6 wherein the filter comprises a finite impulse response filter.

8. The apparatus of claim 1 wherein the information specifying an adjustment to one or more equalization parameters of the transmitter of the first node comprises for a particular one of a plurality of coefficients at least one of an increment coefficient action, a decrement coefficient action, and a hold coefficient action.

9. The apparatus of claim 1 wherein the information specifying an adjustment to one or more equalization parameters of the transmitter of the first node is transmitted utilizing a link services command format compliant with the Fibre Channel standard.

10. The apparatus of claim 1 wherein the information specifying an adjustment to one or more equalization parameters of the transmitter of the first node comprises a request command transmitted utilizing a Basic Link Services (BLS) command format.

11. The apparatus of claim 10 wherein the request command is inserted in a frame header, and comprises a command code and a parameter field specifying a particular action.

12. The apparatus of claim 1 wherein the information specifying an adjustment to one or more equalization parameters of the transmitter of the first node comprises a request command transmitted utilizing an Extended Link Services (ELS) command format.

13. The apparatus of claim 12 wherein the request command is inserted in a frame payload, and comprises a command code and a parameter field specifying a particular action.

14. The apparatus of claim 1 wherein the adjustment of the one or more equalization parameters of the transmitter of the first node is applied after a Fibre Channel link is established between the first and second nodes.

15. The apparatus of claim 1 wherein the adjustment of the one or more equalization parameters of the transmitter of the first node is repeated periodically so as to provide substantially continuous transmit adaptive equalization.

16. The apparatus of claim 1 wherein a transmit adaptive equalization process implemented by the first and second nodes is carried out substantially during an otherwise idle period in data communication between the first and second nodes.

17. The apparatus of claim 1 wherein the first node is implemented at least in part as an integrated circuit.

18. An integrated circuit for use in a communication system having a plurality of nodes, the integrated circuit implementing at least a portion of a first node, the first node comprising a transmitter configured for communication with a receiver of a second node and a receiver configured for communication with a transmitter of the second node, the first node being operative:

(i) to receive in the receiver of the first node from the transmitter of the second node, responsive to a signal transmitted by the transmitter of the first node to the receiver of the second node, information specifying an adjustment to one or more equalization parameters of the transmitter of the first node, and (ii) to adjust the one or more equalization parameters in accordance with the received information.

19. A method for use in a communication system having a plurality of nodes, including at least a first node comprising a transmitter configured for communication with a receiver of a second node and a receiver configured for communication with a transmitter of the second node, the method comprising the steps of:

receiving in the receiver of the first node from the transmitter of the second node, responsive to a signal transmitted by the transmitter of the first node to the receiver of the second node, information specifying an adjustment to one or more equalization parameters of the transmitter of the first node; and

adjusting the one or more equalization parameters in accordance with the received information.

20. An article of manufacture comprising a machine-readable storage medium having one or more software programs stored therein, for use in a communication system having a plurality of nodes, including at least a first node comprising a transmitter configured for communication with a receiver of a second node and a receiver configured for communication with a transmitter of the second node, the first node being operative under control of the one or more software programs to perform the steps of:

receiving in the receiver of the first node from the transmitter of the second node, responsive to a signal transmitted by the transmitter of the first node to the receiver of the second node, information specifying an adjustment to one or more equalization parameters of the transmitter of the first node; and

adjusting the one or more equalization parameters in accordance with the received information.

21. An apparatus for use in a communication system having a plurality of nodes, the apparatus comprising:

a first node comprising a transmitter configured for communication with a receiver of a second node and a receiver configured for communication with a transmitter of the second node;

the first node being operative to adjust one or more equalization parameters of its associated transmitter, responsive to information received from the second node in conjunction with a transmit adaptive equalization process, the process being implemented substantially during an otherwise idle period in data communication between the first and second nodes.