signal splitting method for limiting peak power in a CDMA system

• US 20010024449A1
• Filed: 05/29/2001
• Published: 09/27/2001
• Est. Priority Date: 08/31/1998
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Tiedemann, Edward G. Jr., Lundby, Stein A., Holtzman, Jack M., Terasawa, Daisuke
• Granted Patent: US 7,251,225 B2
• Time in Patent Office: Days
• US Class Current: 370/441
• CPC Class Codes: H04B 1/707 using direct sequence modulation
• CPC Class Codes: H04B 2201/70706 with means for reducing the peak-to-average power ratio
• CPC Class Codes: H04B 2201/709709 Methods of preventing interference
• CPC Class Codes: H04W 52/36 with a discrete range or set of values, e.g. step size, ramping or offsets

Abstract

The invention is a method for limiting the peak transmit power in a CDMA communication system. At least one of first and second high transmit power regions are separated into a plurality of high transmit power subregions. The high transmit power subregions of the plurality of high subregions are shifted by time offsets of differing durations to provide a plurality of time offset subregions. First and second low transmit power regions are also provided. At least one of the first and second low transmit power regions is also separated into a plurality of transmit power subregions and the low transmit power subregions are shifted by time offsets of differing time durations. The subregions can be time offset by a predetermined time duration or by a random time duration.

Claims

1. A method for limiting peak transmit power in a wireless communication system, comprising:

providing a transmit waveform;

selecting a non-fixed individual time offset for the waveform according to an algorithm; and

delaying transmission of the waveform by the non-fixed time offset.

2. The method for limiting peak transmit power of

claim 1

wherein the algorithm comprises selecting a time offset by determining which of a possible set of offsets is being used by a lowest number of waveforms.

3. The method for limiting peak transmit power of

claim 1

wherein the algorithm comprises a peak power algorithm adapted to provide a minimum increase in the peak transmit power according to the shape or expected shape of the transmit waveform.

4. The method for limiting peak transmit power of

claim 1

wherein the algorithm comprises a heuristic algorithm.

5. A system for limiting peak transmit power in a wireless communication system, comprising:

means for providing a transmit waveform;

means for selecting a non-fixed individual time offset for the waveform according to an algorithm; and

means for delaying transmission of the waveform by the non-fixed time offset.

6. The system for limiting peak transmit power of

claim 5

wherein the means for selecting a non-fixed individual time offset for the waveform according to an algorithm comprises a means for selecting a time offset by determining which of a possible set of offsets is being used by a lowest number of waveforms.

7. The system for limiting peak transmit power of

claim 5

wherein the means for selecting a non-fixed individual time offset for the waveform according to an algorithm comprises a means for a peak power algorithm to provide a minimum increase in the peak transmit power according to the shape or expected shape of the transmit waveform.

8. The system for limiting peak transmit power of

claim 5

wherein the means for selecting a non-fixed individual time offset for the waveform according to an algorithm comprises a means for performing a heuristic algorithm.