# US 8,788,920 B2 · Detection, avoidance and/or correction of problematic puncturing patterns in parity bit streams used when implementing turbo codes

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- Number: US 8,788,920 B2
- Document ID: US8788920B2
- Status: Granted
- Kind: B2
- Application number: 13/744,984
- Filed: 2013-01-18
- Published: 2013-05-30
- Granted: 2014-07-22
- Earliest claimed: 2002-12-16
- Assignees: InterDigital Technology Corporation
- Applicants: Interdigital Technology Corporation
- Inventors: Philip J. Pietraski; Gregory S. Sternberg
- Web page: https://patentgrep.com/patent/US8788920B2

## CPC

- H03M 13/2771: {Internal interleaver for turbo codes (H03M13/2714 and H03M13/2725 take precedence)}
- H04L 1/0013: {Rate matching, e.g. puncturing or repetition of code symbols}
- H03M 13/2792: {Interleaver wherein interleaving is performed jointly with another technique such as puncturing, multiplexing or routing}
- H03M 13/2957: {Turbo codes and decoding}
- H03M 13/6362: {by puncturing}
- H03M 13/6381: {Rate compatible punctured turbo [RCPT] codes}
- H04L 1/0067: {Rate matching (H04L1/0013 and H04L1/08 take precedence)}
- 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)
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)

## Abstract

Detecting, avoiding and/or correcting problematic puncturing patterns in parity bit streams used when implementing punctured Turbo codes is achieved without having to avoid desirable code rates. This enables identification/avoidance of regions of relatively poor Turbo code performance. Forward error correction comprising Turbo coding and puncturing achieves a smooth functional relationship between any measure of performance and the effective coding rate resulting from combining the lower rate code generated by the Turbo encoder with puncturing of the parity bits. In one embodiment, methods to correct/avoid degradations due to Turbo coding are implemented by puncturing interactions when two or more stages of rate matching are employed.

## Claims

### Claim 1

A method of performing rate matching in a wireless communication terminal, the method comprising:
interleaving a first bit stream to produce an interleaved first bit stream;
interleaving a second bit stream to produce an interleaved second bit stream;
interleaving a third bit stream to produce an interleaved third bit stream;
buffering the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream in a virtual buffer; and
performing rate matching on at least one output of the virtual buffer.

### Claim 2 (depends on 1)

The method of claim 1 wherein the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream are buffered on a condition that the number of bits of the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream is not larger than a size of the virtual buffer.

### Claim 3 (depends on 2)

The method of claim 2, further comprising:
buffering a portion of the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream in the virtual buffer on a condition that the number of bits of the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream is larger than a size of the virtual buffer.

### Claim 4 (depends on 3)

The method of claim 3 wherein the buffered portion of the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream includes all of the interleaved first bit stream.

### Claim 5 (depends on 1)

The method of claim 1, further comprising:
collecting bits associated with the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream.

### Claim 6 (depends on 1)

The method of claim 1 performed by a wireless transmit/receive unit (WTRU).

### Claim 7 (depends on 1)

The method of claim 1 performed by a node B.

### Claim 8

An apparatus for performing rate matching, the apparatus comprising:
a first interleaver configured to interleave a first bit stream to produce an interleaved first bit stream;
a second interleaver configured to interleave a second bit stream to produce an interleaved second bit stream;
a third interleaver configured to interleave a third bit stream to produce an interleaved third bit stream;
a virtual buffer configured to buffer the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream; and
a rate matching unit configured to perform rate matching on at least one output of the virtual buffer.

### Claim 9 (depends on 8)

The apparatus of claim 8 wherein the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream are buffered on a condition that the number of bits of the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream is not larger than a size of the virtual buffer.

### Claim 10 (depends on 9)

The apparatus of claim 9 wherein the virtual buffer is further configured to buffer a portion of the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream on a condition that the number of bits of the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream is larger than a size of the virtual buffer.

### Claim 11 (depends on 10)

The apparatus of claim 10 wherein the buffered a portion of the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream includes all of the interleaved first bit stream.

### Claim 12 (depends on 8)

The apparatus of claim 8, further comprising:
a bit collection unit configured to collect bits associated with the interleaved first bit stream, the interleaved second bit stream and the interleaved third bit stream.

### Claim 13 (depends on 7)

The apparatus of claim 7 configured as a wireless transmit/receive unit (WTRU).

### Claim 14 (depends on 7)

The apparatus of claim 7 configured as a node B.