HIGH-SPEED INTERCONNECT SOLUTIONS WITH SUPPORT FOR CONTINUOUS TIME BACK CHANNEL COMMUNICATION

• US 20190020742A1
• Filed: 10/30/2017
• Published: 01/17/2019
• Est. Priority Date: 07/13/2017
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Inventors: HEALEY, Adam
• Granted Patent: US 10,530,906 B2
• Time in Patent Office: Days
• CPC Class Codes: H04B 3/04 Control of transmission; Equalising
• CPC Class Codes: H04B 3/32 Reducing cross-talk, e.g. by compensating
• CPC Class Codes: H04L 1/0008 by supplementing frame payload, e.g. with padding bits
• CPC Class Codes: H04L 2001/0096 Channel splitting in point-to-point links
• CPC Class Codes: H04L 2025/03375 Passband transmission
• CPC Class Codes: H04L 2025/0377 during the reception of training signals
• CPC Class Codes: H04L 2025/03815 Transmission of a training request
• CPC Class Codes: H04L 25/03006 Arrangements for removing intersymbol interference
• CPC Class Codes: H04L 25/03019 adaptive, i.e. capable of adjustment during data reception
• CPC Class Codes: H04L 25/03343 Arrangements at the transmitter end
• CPC Class Codes: H04L 25/14 Channel dividing arrangements , i.e. in which a single bit stream is divided between several baseband channels and reassembled at the receiver
• CPC Class Codes: H04L 69/323 in the physical layer [OSI layer 1]
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC

Abstract

The present disclosure is directed to systems, apparatuses, and methods for performing continuous or periodic link training. Existing link training protocols generally perform link training only once during startup or initialization of a link and, as a result, are limited in their applications. After link training is performed and Open Systems Interconnect (OSI) data link layer and other high-layer data is transmitted across the link, no further link training is performed using these existing link training protocols. However, parameters of the link may change over time after link training is performed, such as temperature of the link and voltage levels of signals transmitted over the link by the transmitter of the transmitter-receiver pair.

Claims

1. A network device for performing serializer-deserializer communication with a remote link partner (LP) over a transmission line, the network device comprising:

a receiver comprising a decoder configured to extract link training data from a link training communication channel in a signal received from the remote LP over the transmission line, wherein the link training communication channel co-exists with data traffic corresponding to an Open Systems Interconnect (OSI) data link layer and other higher OSI layers in the signal; and

a transmitter comprising a transmitter front-end, an encoder, and an adaptation parameter receiver configured to receive the link training data from the receiver and adjust one or more parameters of the transmitter front-end or the encoder based on the link training data.

2. The network device of claim 1, wherein the link training communication channel is formed using overhead from a Physical Coding Sublayer (PCS) protocol that is part of the OSI networking protocol sublayer.

3. The network device of claim 2, wherein the overhead is pad bits included in alignment markers that are inserted among encoded blocks of the data traffic in the signal by the PCS protocol.

4. The network device of claim 1, wherein the link training communication channel is formed using low-frequency signaling with a frequency that is lower than high-frequency signaling used to transmit the data traffic in the signal.

5. The network device of claim 4, wherein the decoder comprises a low-pass filter configured to filter the signal to extract the link training data from the link training communication channel in the signal.

6. The network device of claim 1, wherein the data traffic appears as a differential mode component in the signal and the link training data appears as a common mode component in the signal.

7. The network device of claim 1, wherein the one or more parameters of the transmitter front-end or the encoder comprise equalizer tap weights, precoder settings, or delay parameters to compensate for differential skew associated with the transmission line.

8. A network device for performing serializer-deserializer communication with a remote link partner (LP) over a transmission line, the network device comprising:

a receiver configured to monitor a signal received from the remote LP over the transmission line to determine a change to one or more parameters of the remote LP; and

a transmitter configured to transmit the change to the one or more parameters of the remote LP over a link training communication channel in a signal transmitted to the remote LP, wherein the link training communication channel co-exists with data traffic corresponding to an Open Systems Interconnect (OSI) data link layer and other higher OSI layers in the signal transmitted to the remote LP.

9. The network device of claim 8, wherein the link training communication channel is formed using overhead from a Physical Coding Sublayer (PCS) protocol that is part of the OSI networking protocol sublayer.

10. The network device of claim 9, wherein the overhead is pad bits included in alignment markers that are inserted among encoded blocks of the data traffic in the signal transmitted to the remote LP by the PCS protocol.

11. The network device of claim 8, wherein the link training communication channel is formed using low-frequency signaling with a frequency that is lower than high-frequency signaling used to transmit the data traffic in the signal transmitted to the remote LP.

12. The network device of claim 11, wherein the transmitter comprises a digital-to-analog converter (DAC) for converting the combination of the low-frequency signaling and the high-frequency signaling from a digital domain to an analog domain.

13. The network device of claim 12, wherein part of a full-scale range of the DAC is reserved for the low-frequency signaling.

14. The network device of claim 8, wherein the one or more parameters of the remote LP comprise equalizer tap weights, precoder settings, or delay parameters to compensate for differential skew associated with the transmission line.

15. A network device for performing serializer-deserializer communication with a remote link partner (LP) over a transmission line, the network device comprising:

a receiver configured to extract link training data from a link training communication channel in a signal received from the remote LP over the transmission line; and

a transmitter configured to receive the link training data from the receiver and adjust one or more parameters of the transmitter based on the link training data,

wherein the link training communication channel co-exists with data traffic corresponding to an Open Systems Interconnect (OSI) data link layer and other higher OSI layers in the signal and is formed using one of;

overhead from a Physical Coding Sublayer (PCS) protocol that is part of the OSI networking protocol sublayer, or low-frequency signaling with a frequency that is lower than high-frequency signaling used to transmit the data traffic in the signal.

16. The network device of claim 15, wherein the overhead is pad bits included in alignment markers that are inserted among encoded blocks of the data traffic in the signal by the PCS protocol.

17. The network device of claim 15, wherein the receiver comprises a low-pass filter configured to filter the signal to extract the link training data from the link training communication channel in the signal.

18. The network device of claim 15, wherein the data traffic appears as a differential mode component in the signal and the link training data appears as a common mode component in the signal.

19. The network device of claim 15, wherein the one or more parameters of the transmitter comprise equalizer tap weights, precoder settings, or delay parameters to compensate for differential skew associated with the transmission line.

20. The network device of claim 15, wherein the network device is a switch.