Methods and systems for high bandwidth communications interface

Patent metadata

Field	Value
Publication number	US-10091035-B2
Application number	US-201715457935-A
Country	US
Kind code	B2
Filing date	Mar 13, 2017
Priority date	Apr 16, 2013
Publication date	Oct 2, 2018
Grant date	Oct 2, 2018

Abstract

Systems and methods are described for transmitting data over physical channels to provide a high bandwidth, low latency interface between a transmitting device and a receiving device operating at high speed with low power utilization. Communication is performed using group signaling over sets of four wires using a vector signaling code, where each wire of a set carries a low-swing signal that may take on one of four signal values. Topologies and designs of wire sets are disclosed with preferred characteristics for group signaling communications.

First claim

We claim:

1. A method comprising:
receiving symbols of a codeword of a balanced vector signaling code via wires of a multi-wire bus;
introducing, via a respective signal summation node on each wire of the multi-wire bus, a corresponding correction signal for each wire, the correction signal generated based on a re-encoded symbol of a re-encoded codeword, the re-encoded codeword obtained by re-encoding a previously-decoded codeword;
forming a plurality of output signals using a plurality of multi-input comparators, each output signal formed by a respective multi-input comparator forming a respective weighted combination of the received symbols of the codeword, the respective weighted combination determined by a corresponding vector of an orthogonal matrix;
forming a plurality of output data bits from the plurality of output signals; and
generating a re-encoded codeword based on the plurality of output data bits for use in a set of symbols of a codeword received in a subsequent unit interval.

2. The method of claim 1 , wherein the symbols of the codeword of the balanced vector signaling code have symbol values selected from the set {±1/3, ±1}.

3. The method of claim 2 , wherein the codeword is a permutation of ±[1, −1/3, −1/3, −1/3].

4. The method of claim 1 , wherein the orthogonal matrix is a Hadamard matrix.

5. The method of claim 4 , wherein the Hadamard matrix is represented as:

H
4

=

[

+
1

+
1

+
1

+
1

+
1

-
1

+
1

-
1

+
1

+
1

-
1

-
1

+
1

-
1

-
1

+
1

]

,

and wherein the respective weighted combinations are represented by respective column vectors that sum to zero.

6. The method of claim 1 , wherein forming the respective combination comprises:
obtaining a respective first sum of a first selected pair of symbols;
obtaining a respective second sum of a second selected pair of symbols; and
comparing the respective first sum and the respective second sum to obtain the respective output signal.

7. The method of claim 1 , wherein the symbols of the re-encoded codeword are digital symbols.

8. The method of claim 1 , wherein each correction signal has one of at least four possible values.

9. The method of claim 1 , further comprising combining un-rolled decision-feedback equalization (DFE) with the plurality of output signals prior to generating the re-encoded codeword.

10. An apparatus comprising:
a set of summation nodes, each summation node configured to receive a respective symbol of a codeword of a balanced vector signaling code via a respective wire of a multi-wire bus and to responsively introduce a corresponding correction signal into the respective wire, the correction signal representing a re-encoded symbol of a re-encoded codeword, the re-encoded codeword obtained by re-encoding a previously-decoded codeword;
a plurality of multi-input comparators configured to form a plurality of output signals, each multi-input comparator configured to form a respective output signal by forming a respective weighted combination of the received symbols of the codeword, the respective weighted combination determined by a corresponding vector of an orthogonal matrix;
a plurality of slicers configured to receive the plurality of output signals and to responsively generate a plurality of output data bits; and
an encoder configured to generate a re-encoded codeword based on the output data bits for use in a set of symbols of a codeword received in a subsequent unit interval.

11. The apparatus of claim 10 , wherein the symbols of the codeword of the balanced vector signaling code have symbol values selected from the set {±1/3, ±1}.

12. The apparatus of claim 11 , wherein the codeword is a permutation of ±[1, −1/3, −1/3, −1/3].

13. The apparatus of claim 10 , wherein the orthogonal matrix is a Hadamard matrix.

14. The apparatus of claim 13 , wherein the Hadamard matrix is represented as:

H
4

=

[

+
1

+
1

+
1

+

Assignees

• Kandou Labs SA

Inventors

• Fox John
• Holden Brian
• Hormati Ali
• Hunt Peter
• Keay John D
• Shokrollahi Amin
• Simpson Richard
• Singh Anant
• Stewart Andrew Kevin John
• Surace Giuseppe
• Ulrich roger

Classifications

• H04L25/03057

  with a recursive structure (H04L25/03031 takes precedence) · CPC title

• H04L25/0272

  Arrangements for coupling to multiple lines, e.g. for differential transmission · CPC title

• H04L5/02 Primary

  Channels characterised by the type of signal · CPC title

• H03M5/04

  the pulses having two levels · CPC title

• H04L25/03343

  Arrangements at the transmitter end · CPC title