# US 2014/0192924 A1 · Method and system for reduction of peak-to-average power ratio of transmission signals comprising overlapping waveforms

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- Number: US 2014/0192924 A1
- Document ID: US20140192924A1
- Status: Published application
- Kind: A1
- Application number: 14/203,227
- Filed: 2014-03-10
- Published: 2014-07-10
- Earliest claimed: 1999-06-02
- Assignees: AT&T Intellectual Property II, L.P.
- Applicants: AT&T Intellectual Property II, L.P.
- Inventors: LEONARD JOSEPH CIMINI, JR.; Nelson Ray Sollenberger
- Web page: https://patentgrep.com/patent/US20140192924A1

## CPC

- H04L 27/2623: {Reduction thereof by clipping}
- H04B 1/0475: {with means for limiting noise, interference or distortion (H04B1/0483 takes precedence)}
- H04B 7/2628: {using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] (H04B7/2618 takes precedence)}
- H04L 27/2614: {Peak power aspects}
- H04L 27/2621: {Reduction thereof using phase offsets between subcarriers}
- H04B 2201/70706: with means for reducing the peak-to-average power ratio
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- H04B: TRANSMISSION

## Abstract

The present invention provides a method and system for reducing the peak to average power ratio (PAP) of a signal with low computational complexity. According to one embodiment, the present invention is applied to reduce the PAP of an OFDM signal. According to an alternative embodiment, the present invention, is applied to reduce the PAP of a CDMA signal. Rather than seeking the optimum solution, which involves significant computational complexity, the present invention provides for a number of sub-optimal techniques for reducing the PAP of an OFDM signal but with much lower computational complexity.

## Claims

### Claim 1

A method for minimizing a first peak to average power ratio value, comprising:
calculating, by a processor, the first peak to average power ratio value of a signal comprising a combination of: each of a plurality of vectors associated with a signal being multiplied by a corresponding phase factor assigned to each of the plurality of vectors, wherein the phase factor comprises a binary value; and
assigning, by the processor, a final phase factor to each of the plurality of vectors, wherein the final phase factor is assigned on a basis that the first peak to average power ratio value of the signal is to be minimized.

### Claim 2 (depends on 1)

The method of claim 1, wherein the signal is an orthogonal frequency division multiplexed signal.

### Claim 3 (depends on 1)

The method of claim 1, wherein the signal is a wireless signal transmitted using code division multiple access.

### Claim 4 (depends on 1)

The method of claim 1, wherein the signal is a wireless signal transmitted using multicode code division multiple access.

### Claim 5 (depends on 1)

The method of claim 1, wherein the plurality of vectors comprises partial transmit sequences.

### Claim 6 (depends on 1)

The method of claim 1, wherein the binary value comprises either a 1 value or a −1 value.

### Claim 7

A transmitter, comprising:
a transponder device;
a memory; and
a processor coupled to the memory and the transponder device, the processor for:
calculating a first peak to average power ratio value of a signal comprising a combination of: each of a plurality of vectors associated with a signal being multiplied by a corresponding phase factor assigned to each of the plurality of vectors, wherein the phase factor comprises a binary value; and
assigning a final phase factor to each of the plurality of vectors, wherein the final phase factor is assigned on a basis that the first peak to average power ratio value of the signal is to be minimized.

### Claim 8 (depends on 7)

The transmitter of claim 7, wherein the signal is an orthogonal frequency division multiplexed signal.

### Claim 9 (depends on 7)

The transmitter of claim 7, wherein the signal is a wireless signal transmitted using code division multiple access.

### Claim 10 (depends on 7)

The transmitter of claim 7, wherein the signal is a wireless signal transmitted using multicode code division multiple access.

### Claim 11 (depends on 7)

The transmitter of claim 7, wherein the plurality of vectors comprises partial transmit sequences.

### Claim 12 (depends on 7)

The transmitter of claim 7, wherein the binary value comprises either a 1 value or a −1 value.

### Claim 13

An apparatus for minimizing a first peak to average power ratio value comprising:
a processor
and a memory, the processor and the memory for performing operations, the operations comprising:
calculating the first peak to average power ratio value of a signal comprising a combination of: each of a plurality of vectors associated with a signal being multiplied by a corresponding phase factor assigned to each of the plurality of vectors, wherein the phase factor comprises a binary value; and
assigning a final phase factor to each of the plurality of vectors, wherein the final phase factor is assigned on a basis that the first peak to average power ratio value of the signal is to be minimized.

### Claim 14 (depends on 13)

The apparatus of claim 13, wherein the signal is an orthogonal frequency division multiplexed signal.

### Claim 15 (depends on 13)

The apparatus of claim 13, wherein the signal is a wireless signal transmitted using code division multiple access.

### Claim 16 (depends on 13)

The apparatus of claim 13, wherein the signal is a wireless signal transmitted using multicode code division multiple access.

### Claim 17 (depends on 13)

The apparatus of claim 13, wherein the plurality of vectors comprises partial transmit sequences.

### Claim 18 (depends on 13)

The apparatus of claim 13, wherein the binary value comprises either a 1 value or a −1 value.