Method and apparatus for reducing peak to average power ratio of a multi-carrier signal

• US 7,266,156 B2
• Filed: 04/26/2002
• Issued: 09/04/2007
• Est. Priority Date: 04/26/2002
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Black, Peter J., Montojo, Juan
• Primary Examiner(s): Lugo; David B.
• Application Number:
  US10/132,992
• Publication Number:
  US 20030202611A1
• Time in Patent Office: 1,957 Days
• Field of Search: 375/141, 375/146, 375/260, 375/261, 375/267, 375/279, 375/284, 375/285, 375/296, 375/297, 375/298, 375/299, 375/308
• US Class Current: 375/267
• CPC Class Codes: H04L 27/2621 Reduction thereof using phase offsets between subcarriers
• CPC Class Codes: H04L 5/0019 in which one code is applied, as a temporal sequence, to all frequencies
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver

Abstract

An apparatus and method provide for producing a multi-carrier signal at a reduced peak to average power ratio. A control system (401) determines a number of carriers in multi-carrier signal, determines chip time of a spreading sequence used for spreading the number of carriers and determines delay time for each of the number of carriers based on the determined number of carriers and the determined chip time. Delay blocks (512B, 512C) delay the number of carriers by the determined delay time. A combiner (502) combines the delayed carriers to produce a reduced peak to average power ratio multi-carrier signal (504). A transmitter (500) transmits the reduced peak to average power ratio multi-carrier signal (504). The transmitter (500) may include an amplifier (520) for amplifying the reduced peak to average power ratio multi-carrier signal (504) before transmitting.

Claims

1. An apparatus for producing a multi-carrier signal at a reduced peak to average power ratio, comprising:

a control system for determining a N number of carriers in said multi-carrier signal, N being greater than one, determining chip time of a spreading sequence used for spreading said number of carriers and determining one or more delay times for N-1 carriers based on said determined number of carriers and said determined chip time, wherein one delay time is approximately equal to the chip time divided by N, and wherein said chip time is approximately equal to the inverse of the spreading sequence frequency;

at least one first up-converter for up-converting each of the N-1 carriers to a frequency, wherein each of the N-1 carriers are up-converted to a different frequency;

means for delaying N-1 carriers by said determined one or more delay times;

a combiner for combining the N-1 delayed carriers with a single non-delayed carrier to produce a reduced peak to average power ratio multi-carrier signal; and

a second up-converter for up-converting the combined carriers to a single carrier frequency.

2. The apparatus as recited in claim 1 further comprising:

a transmitter for transmitting said reduced peak to average power ratio multi-carrier signal.

3. The apparatus as recited in claim 2 wherein said transmitter includes a power amplifier for amplifying said reduced peak to average power ratio multi-carrier signal before transmission.

4. A method for producing a multi-carrier signal at a reduced peak to average power ratio, comprising:

determining a N number of carriers in said multi-carder signal, N being greater than one, determining chip time of a spreading sequence used for spreading said number of carriers and determining one or more delay times for N-1 carriers based on said chip time and said determined number of carriers, wherein one delay time is approximately equal to the chip time divided by N, and wherein said chip time is approximately equal to the inverse of the spreading sequence frequency;

at least one first up-converter for up-converting each of the N-1 carriers to a frequency, wherein each of the N-1 carriers are up-converted to a different frequency;

delaying N-1 carriers by said determined one or more delay times;

combining the N-1 delayed carriers with a single non-delayed carrier to produce a reduced peak to average power ratio multi-carrier signal; and

a second up-converter for up-converting the combined carriers to a single carrier frequency.

5. The method as recited in claim 4 further comprising:

transmitting said reduced peak to average power ratio multi-carder signal.

6. The method as recited in claim 5 wherein said transmitting includes amplifying said reduced peak to average power ratio multi-carrier signal before transmitting.

7. An apparatus for producing a multi-carrier signal at a reduced peak to average power ratio, comprising:

a plurality of modulators for modulating data for transmission over said multi-carrier signal, thereby producing a corresponding plurality of N modulated carder signals;

at least one first up-converter for up-converting N-1 modulated carrier signals to a frequency, wherein each of the N-1 modulated carrier signals are up-converted to a different frequency;

means for delaying N-1 modulated carrier signals by one or more determined delay times, wherein said delay times are based on the N number of carriers in said plurality of modulated carrier signals and chip time of a spreading sequence used for spreading said plurality of modulated carrier signals, one delay time is approximately equal to the chip time divided by N, and the chip time is approximately equal to the inverse of the spreading sequence frequency;

a combiner for combining the N-1 delayed plurality of modulated carrier signals with a single non-delayed modulated carrier signal to produce a reduced peak to average power ratio multi-carrier signal; and

a second up-converter for up-converting the combined modulated carrier signals to a single carrier frequency.

8. The apparatus as recited in claim 7 further comprising:

a transmitter for transmitting said reduced peak to average power ratio multi-carrier signal.

9. The apparatus as recited in claim 8 wherein said transmitter includes a power amplifier for amplifying said reduced peak to average power ratio multi-carrier signal before transmission.

10. A method for producing a multi-carrier signal at a reduced peak to average power ratio, comprising:

modulating data for transmission over said multi-carrier signal, thereby producing a corresponding plurality of N modulated carrier signals;

up-converting N-1 modulated carrier signals to a frequency using at least one first up-converter, wherein each of the N-1 modulated carrier signals are up-converted to a different frequency;

delaying N-1 modulated carrier signals by one or more determined delay times, wherein said delay times are based on the N number of carriers in said plurality of modulated carrier signals and chip time of a spreading sequence used for spreading said plurality of modulated carrier signals, one delay time is approximately equal to the chip time divided by N, and the chip time is approximately equal to the inverse of the spreading sequence frequency;

combining the N-1 delayed plurality of modulated carrier signals with a single non-delayed modulated carrier signal to produce a reduced peak to average power ratio multi-carrier signal; and

up-converting the combined modulated carrier signals to a single carrier frequency using a second up-converter.

11. The method as recited in claim 10 further comprising:

transmitting said reduced peak to average power ratio multi-carrier signal.

12. The method as recited in claim 11 wherein said transmitting includes amplifying said reduced peak to average power ratio multi-carrier signal before transmitting.

13. An apparatus for producing a multi-carrier signal, the apparatus comprising:

a plurality of transmit channel processing blocks configured to spread each of a plurality of N carriers using a spreading sequence having a chip time, N being greater than one;

at least one first up-converter configured to up-convert N-1 carriers to a frequency, wherein each of the N-1 carriers are up-converted to a different frequency;

at least one delay block configured to delay one carrier of the plurality of carriers by a delay time based on the chip time, the delay time being approximately equal to the chip time divided by N, the chip time being approximately equal to the inverse of the spreading sequence frequency;

a combiner configured to combine the plurality of carriers to produce the multi-carrier signal; and

a second up-converter configured to up-convert the combined plurality of carriers to a single carrier frequency.

14. An apparatus in accordance with claim 13, wherein the at least one delay block comprises:

a plurality of delay blocks, each delay block configured to delay one of the plurality of carriers by a unique delay time based on the chip time and the total number of carriers to produce a plurality of delayed carriers such that the multi-carrier signal has a reduced peak to average power ratio.

15. An apparatus in accordance with claim 14, where the unique delay time is a multiple of a ratio of the chip time to the total number of carriers.

16. An apparatus in accordance with claim 15, further comprising:

a control system configured to determine the unique delay times.

17. A method for reducing a peak to average power ratio of a multi-carrier signal, the method comprising:

spreading each of a plurality of N carriers using a spreading sequence having a chip time, N being greater than one;

up-converting N-1 carriers to a frequency using at least one first up-converter, wherein each of the N-1 carriers are up-converted to a different frequency;

delaying at least one carrier of the plurality of carriers by a delay time based on the chip time, the delay time being approximately equal to the chip time divided by N, the chip time being approximately equal to the inverse of the spreading sequence frequency;

combining the plurality of carriers to produce the multi-carrier signal; and

up-converting the combined plurality of carriers to a single carrier frequency using a second up-converter.

18. A method in accordance with claim 17, wherein the delaying comprises:

delaying each of the plurality of carriers by a unique delay time based on the chip time and the total number of carriers to produce a plurality of delayed carriers such that the multi-carrier signal has a reduced peak to average power ratio.

19. A method in accordance with claim 18, where the unique delay time is a multiple of a ratio of the chip time to the total number of carriers.

20. A method in accordance with claim 19, further comprising:

determining the unique delay times.