# US 11,121,807 B2 · Methods and systems for determining stress on a low density parity check (LDPC) process for a network using orthogonal frequency division multiplexing (OFDM)

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- Number: US 11,121,807 B2
- Document ID: US11121807B2
- Status: Granted
- Kind: B2
- Application number: 16/785,778
- Filed: 2020-02-10
- Published: 2021-08-12
- Granted: 2021-09-14
- Earliest claimed: 2020-02-10
- Assignees: Viavi Solutions Inc.
- Applicants: Viavi Solutions Inc.
- Inventors: Robert Flask; Loren Eggert
- Web page: https://patentgrep.com/patent/US11121807B2

## CPC

- H04L 1/005: {Iterative decoding, including iteration between signal detection and decoding operation}
- H04L 1/0057: {Block codes (H04L1/0061, H04L1/0064 take precedence)}
- H03M 13/1111: {Soft-decision decoding, e.g. by means of message passing or belief propagation algorithms}
- H03M 13/1128: {Judging correct decoding and iterative stopping criteria other than syndrome check and upper limit for decoding iterations}
- H04L 1/203: {Details of error rate determination, e.g. BER, FER or WER}
- H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT}
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H03M: CODING; DECODING; CODE CONVERSION IN GENERAL (using fluidic means F15C4/00; optical analogue/digital converters G02F7/00; coding, decoding or code conversion, specially adapted for particular applications, see the relevant subclasses, e.g. G01D, G01R, G06F, G06T, G09G, G10L, G11B, G11C, H04B, H04L, H04M, H04N; ciphering or deciphering for cryptography or other purposes involving the need for secrecy G09C)

## Abstract

A method, an apparatus and a system for determining stress on a low density parity check (LDPC) process for a network using orthogonal frequency division multiplexing (OFDM).

## Claims

### Claim 1

A computer-implemented method comprising:
inputting, at a test instrument connected to a channel of a network transmitting signals using orthogonal frequency division multiplexing (OFDM), data received from the signals transmitted over the network, the received data comprising at least one parameter associated with a low density parity check (LDPC) process performed by the network for a profile of the channel; and
determining an LDPC stress level for the profile based on the at least one parameter,
wherein the at least one parameter comprises a number of received codewords on the profile and an LDPC iteration count for the profile and the LDPC stress level is determined an average LDPC iteration count per received codeword.

### Claim 2 (depends on 1)

The method of claim 1 further comprising outputting the determined LDPC stress level on a display of the test instrument.

### Claim 3 (depends on 1)

The method of claim 1, further comprising determining an LDPC performance level based on the determined LDPC stress level.

### Claim 4 (depends on 3)

The method of claim 3, wherein the at least one parameter comprises a maximum number of LDPC iterations per codeword, and determining the LDPC performance level comprises determining a ratio of determined the LDPC stress level to the maximum number of LDPC iterations per codeword.

### Claim 5 (depends on 3)

The method of claim 3, wherein the at least one parameter comprises a maximum number of LDPC iterations per codeword, and determining the LDPC performance level comprises normalizing the determined the LDPC stress level to a scaled range based on the maximum number of LDPC iterations per codeword.

### Claim 6 (depends on 3)

The method of claim 3 further comprising outputting the determined LDPC performance level on a display of the test instrument.

### Claim 7

A test instrument configured to be connected to a channel of a network transmitting signals using orthogonal frequency division multiplexing (OFDM), said test instrument comprising:
a storage device; and
a processor executing program instructions stored in the storage device to:
input data received from the signals transmitted over the network, the received data comprising at least one parameter associated with a low density parity check (LPDC) process performed by the network for a profile of the channel; and
determine an LDPC stress level for the profile based on the at least one parameter,
wherein the at least one parameter comprises a number of received codewords on the profile and an LDPC iteration count for the profile and the LDPC stress level is determined an average LDPC iteration count per received codeword.

### Claim 8 (depends on 7)

The test instrument of claim 7, further comprising a display, wherein the processor executes instructions to output the determined LDPC stress level on a display of the test instrument.

### Claim 9 (depends on 7)

The test instrument of claim 7, wherein the processor executes instructions to determine an LDPC performance level based on the determined LDPC stress level.

### Claim 10 (depends on 9)

The test instrument of claim 9, wherein the at least one parameter comprises a maximum number of LDPC iterations per codeword, and determining the LDPC performance level comprises determining a ratio of determined the LDPC stress level to the maximum number of LDPC iterations per codeword.

### Claim 11 (depends on 9)

The test instrument of claim 9, wherein the at least one parameter comprises a maximum number of LDPC iterations per codeword, and determining the LDPC performance level comprises normalizing the determined the LDPC stress level to a scaled range based on the maximum number of LDPC iterations per codeword.

### Claim 12 (depends on 9)

The test instrument of claim 9, further comprising a display, wherein the processor executes instructions to output the determined LDPC performance level on a display of the test instrument.