Orthogonal differential vector signaling

• US 9,288,089 B2
• Filed: 05/20/2010
• Issued: 03/15/2016
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: Ecole polytechnique fãdãrale de lausanne epfl (Schweizerische Eidgenossenschaft)
• Original Assignee: Ecole polytechnique fãdãrale de lausanne epfl (Schweizerische Eidgenossenschaft)
• Inventors: Cronie, Harm, Shokrollahi, Amin
• Primary Examiner(s): Harper, Kevin C
• Assistant Examiner(s): Rose, Derrick V
• Application Number:
  US12/784,414
• Publication Number:
  US 20110268225A1
• Time in Patent Office: 2,126 Days
• Field of Search: 370/476, 370/208, 370/420, 708/400, 375/256, 375/257, 375/243
• US Class Current: 1/1
• CPC Class Codes: H04B 10/54 Intensity modulation
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04L 25/0272 Arrangements for coupling to multiple lines, e.g. for differential transmission
• CPC Class Codes: H04L 25/085 Arrangements for reducing interference in line transmission systems, e.g. by differential transmission
• CPC Class Codes: H04L 25/4906 using binary codes
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT

Abstract

Using a transformation based at least in part on a non-simple orthogonal or unitary matrix, data may be transmitted over a data bus in a manner that is resilient to one or more types of signal noise, that does not require a common reference at the transmission and acquisition points, and/or that has a pin-efficiency that is greater than 50% and may approach that of single-ended signaling. Such transformations may be implemented in hardware in an efficient manner. Hybrid transformers that apply such transformations to selected subsets of signals to be transmitted may be used to adapt to various signal set sizes and/or transmission environment properties including noise and physical space requirements of given transmission environments.

Claims

1. A method of transmitting information over a multi-wire data bus, the method comprising:

receiving a set of bits in parallel and responsively forming a first set of signals, wherein each signal in the first set has an analog value selected from a respective set of two possible analog values;

forming a second set of signals based at least in part on the first set of signals and a set of rows of a non-simple orthogonal or unitary matrix, wherein each row of the set of rows is (i) associated with a respective signal of the first set of signals and (ii) orthogonal to a common mode row having all ones; and

providing the second set of signals in analog form for transmission over the multi-wire data bus, wherein each signal of the second set of signals is transmitted over a respective wire of the multi-wire data bus.

2. A method of transmitting information according to claim 1, further comprising:

forming the first set of signals based at least in part on a balancing transformation that at least ensures that the first set of signals has a size matching a size of the non-simple orthogonal or unitary matrix.

3. A method of transmitting information according to claim 2, wherein the size of the first set of physical signals is larger than a size of the set of bits.

4. A method of transmitting information according to claim 1, wherein at least one of the second set of signals has an analog signal value corresponding to a matrix multiplication of the non-simple orthogonal or unitary matrix with a vector having entries corresponding to the analog signal values of the first set of signals.

5. A method of transmitting information according to claim 4, wherein the entries of the vector correspond to real numbers.

6. A method of transmitting information according to claim 4, wherein the entries of the vector correspond to complex numbers.

7. A method of transmitting information according to claim 1, wherein the non-simple orthogonal or unitary matrix is a Hadamard matrix.

8. A method of transmitting information according to claim 1, wherein the non-simple orthogonal or unitary matrix is a Hadamard matrix having a size of at least 3.

9. A method of transmitting information according to claim 1, wherein the non-simple orthogonal or unitary matrix is a Hadamard matrix of Sylvester type.

10. A method of transmitting information according to claim 9, wherein forming the second set of signals comprises applying a Fast Hadamard-Walsh Transform configured with the Hadamard matrix of Sylvester type to the first set of signals.

11. A method of transmitting information according to claim 1, further comprising:

receiving a third set of signals corresponding to the second set of signals; and

forming a fourth set of signals based at least in part on the third set of physical signals and the non-simple orthogonal or unitary matrix, the fourth set of signals corresponding to the first set of signals.

12. A method of transmitting information according to claim 1, wherein the method has a pin-efficiency greater than 50%.

13. A method of transmitting information according to claim 12, wherein the pin-efficiency of the method is greater than 66%.

14. A method of transmitting information according to claim 12, wherein the pin-efficiency of the method is less than 100%.

15. A method of transmitting information according to claim 1, wherein the method has a higher noise resistance than a single-ended signaling method of transmitting the information.

16. A method of transmitting information over a multi-wire data bus incorporating multiple signal paths using analog signals, comprising:

receiving input signals in parallel representing the information, wherein each input signal has a value selected from a respective set of two possible values;

allocating the input signals to a plurality of input signal subsets;

forming a plurality of transmission sets of signals corresponding to the plurality of input signal sets, each of the plurality of the transmission sets of signals based at least in part on a corresponding one of the plurality of input signal subsets, at least one of the plurality of transmission sets of signals being transformed from at least one corresponding input signal subset in accordance with at least one set of rows of at least one non-simple orthogonal or unitary matrix, wherein each row of the at least one set of rows is (i) associated with a respective signal of the input signals and (ii) orthogonal to a common mode row having all ones; and

providing the plurality of transmission sets of signals for transmission over the multi-wire data bus using a single set of signal path drivers.

17. A method of transmitting information according to claim 16, further comprising:

receiving a plurality of transmitted sets of analog signals corresponding to the plurality of transmission sets of signals; and

forming an output set of signals based at least in part on the plurality of transmitted sets of analog signals, at least some of the output set of signals being transformed from at least one of the plurality of transmitted sets of analog signals corresponding to said at least one of the plurality of transmission sets of analog signals in accordance with said at least one set of rows of the at least one non-simple orthogonal or unitary matrix.

18. A system for transmitting information, comprising:

a multi-wire data bus configured at least to transmit a transmission set of analog signals; and

a signal encoder configured to, at least;

receive an input set of signals in parallel representing the information, each input signal having a value selected from a respective set of at least two values;

form the transmission set of analog signals based at least in part on the input set of signals and a set of rows of a non-simple orthogonal or unitary matrix, wherein each row of the set of rows is (i) associated with a respective input signal of the input set of signals and (ii) orthogonal to a common mode row having all ones; and

provide the transmission set of analog signals to the multi-wire data bus for transmission, wherein each signal of the transmission set is transmitted over a respective wire of the multi-wire data bus.

19. A system for transmitting information in accordance with claim 18, further comprising a signal balancer configured to, at least:

receive an unbalanced set of signals; and

form the input set of signals based at least in part on the unbalanced set of signals and a balancing transformation that at least ensures that the input set of signals has a size matching a size of the non-simple orthogonal or unitary matrix.

20. A system for transmitting information in accordance with claim 18, further comprising a signal decoder configured to, at least:

receive a transmitted set of analog signals from the data bus corresponding to the transmission set of analog signals; and

form an output set of signals based at least in part on the transmitted set of analog signals and the non-simple orthogonal or unitary matrix, the output set of signals corresponding to the input set of signals.

21. A system for transmitting information in accordance with claim 20, wherein the signal encoder and the signal decoder are implemented with substantially similar components.

22. A system for transmitting information in accordance with claim 20, further comprising:

a first component of a processor configured at least to provide a set of signals corresponding to the input set of signals; and

a second component of the processor configured at least to receive a set of signals corresponding to the output set of signals.

23. A system for transmitting information in accordance with claim 18, wherein the signal encoder comprises a plurality of analog signal adders, a plurality of analog signal subtractors, and a plurality of analog signal multipliers interconnected by a plurality of signal paths.

24. A system for transmitting information in accordance with claim 18, wherein the multi-wire data bus includes at least two pairs of wires and the non-simple orthogonal or unitary matrix is of size at least 4.

25. A system for transmitting information in accordance with claim 18, wherein the multi-wire data bus includes at least two optical fibers.