Multi-channel peak power smoothing

• US 20020142739A1
• Filed: 03/27/2001
• Published: 10/03/2002
• Est. Priority Date: 03/27/2001
• Status: Active Grant

• Current Assignee: Northrop Grumman Systems Corporation (Northrop Grumman Corporation)
• Original Assignee: Northrop Grumman Corporation
• Inventors: Smith, Andrew D.
• Granted Patent: US 6,771,940 B2
• Time in Patent Office: Days
• US Class Current: 455/103
• CPC Class Codes: H04L 27/2618 Reduction thereof using auxiliary subcarriers

Abstract

A multi-channel transmission system and method provide peak power smoothing without additional in-band interference. The system includes a multi-carrier waveform generator for reducing peak amplifier power required to transmit a digital multi-carrier waveform based on a plurality of digital carrier waveforms. A signal conversion system generates an analog multi-carrier waveform based on the digital multi-carrier waveform. The analog multi-carrier waveform has a center frequency and a desired gain over the original signal. A bandpass filter is coupled to the signal conversion system for restriction of the analog multi-carrier output waveform to a desired transmission bandwidth. The multi-carrier waveform generator has a nulling waveform generator coupled to a plurality of single carrier waveform modules for generating a digital nulling waveform based on the retrieved data. The nulling waveform reduces a peak power of the multi-carrier waveform and results in a reduced signal envelope.

Claims

1. A multi-channel transmission system comprising:

a multi-carrier waveform generator for increasing a bandwidth of a digital multi-carrier waveform based on data from a plurality of digital carrier waveforms;

a signal conversion system coupled to the multi-carrier waveform generator, the signal conversion system generating an analog multi-carrier waveform based on the digital multi-carrier waveform, the analog multi-carrier waveform having a desired center frequency and a desired gain; and

a bandpass filter coupled to the signal conversion system for decreasing a bandwidth of the analog multi-carrier waveform to a desired transmission bandwidth.

2. A multi-channel transmission system comprising:

a multi-carrier waveform generator for increasing a bandwidth of a digital multi-carrier waveform based on data from a plurality of digital carrier waveforms, the multi-carrier waveform generator including;

a plurality of single carrier waveform modules for retrieving data from a plurality of digital carrier waveforms, the digital carrier waveforms having power within the transmission bandwidth;

a nulling waveform generator coupled to the single carrier waveform generators for generating a digital nulling waveform based on the retrieved data, the digital nulling waveform having power outside the transmission bandwidth; and

a digital summer coupled to the waveform modules and the waveform generator for generating the digital multi-carrier waveform based on the carrier waveforms and the nulling waveform such that the nulling waveform reduces a peak power of the digital multi-carrier waveform;

a signal conversion system coupled to the multi-carrier waveform generator, the signal conversion system generating an analog multi-carrier waveform based on the digital multi-carrier waveform, the analog multi-carrier waveform having a desired center frequency and a desired gain; and

a bandpass filter coupled to the signal conversion system for decreasing a bandwidth of the analog multi-carrier waveform to a desired transmission bandwidth.

3. The transmission system of claim 2 wherein the nulling waveform generator generates the digital nulling waveform based on data regarding predicted collisions between the digital carrier waveforms.

4. The transmission system of claim 3 wherein the data regarding predicted collisions includes collision timing data.

5. The transmission system of claim 3 wherein the data regarding predicted collisions includes collision duration data.

6. The transmission system of claim 3 wherein the data regarding predicted collisions includes collision amplitude data.

8. The transmission system of claim 2 wherein the digital summer adds the digital carrier waveforms and the digital nulling waveform together.

7. A multi-channel transmission system comprising:

a multi-carrier waveform generator for increasing a bandwidth of a digital multi-carrier waveform based on data from a plurality of digital carrier waveforms, the multi-carrier waveform generator including;

a plurality of single carrier waveform modules for retrieving data from a plurality of digital carrier waveforms, the digital carrier waveforms having power within the transmission bandwidth;

a nulling waveform generator coupled to the single carrier waveform generators for generating a digital nulling waveform based on the retrieved data, the digital nulling waveform generating a sinc waveform having power at frequencies above the transmission bandwidth and power at frequencies below the transmission bandwidth; and

a digital summer coupled to the waveform modules and the waveform generator for generating the digital multi-carrier waveform based on the carrier waveforms and the nulling waveform such that the nulling waveform reduces a peak power of the digital multi-carrier waveform;

a signal conversion system coupled to the multi-carrier waveform generator, the signal conversion system generating an analog multi-carrier waveform based on the digital multi-carrier waveform, the analog multi-carrier waveform having a desired center frequency and a desired gain; and

a bandpass filter coupled to the signal conversion system for decreasing a bandwidth of the analog multi-carrier waveform to a desired transmission bandwidth..

9. A multi-channel transmission system comprising:

a multi-carrier waveform generator for increasing a bandwidth of a digital multi-carrier waveform based on data from a plurality of digital carrier waveforms;

a signal conversion system coupled to the multi-carrier waveform generator, the signal conversion system generating an analog multi-carrier waveform based on the digital multi-carrier waveform, the analog multi-carrier waveform having a desired center frequency and a desired gain, the signal conversion system including;

a digital-to-analog (D/A) converter coupled to the multi-carrier waveform generator for converting the digital multi-carrier waveform into the analog multi-carrier waveform;

a frequency converter coupled to the D/A converter for converting an initial center frequency of the analog multi-carrier waveform into the desired center frequency; and

a power amplifier coupled to the frequency converter for amplifying the analog multi-carrier waveform based on the desired gain; and

a bandpass filter coupled to the signal conversion system for decreasing a bandwidth of the analog multi-carrier waveform to a desired transmission bandwidth.

10. A multi-carrier waveform generator comprising:

a plurality of single carrier waveform modules for retrieving data from a plurality of digital carrier waveforms each having power within a transmission bandwidth;

a nulling waveform generator coupled to the single carrier waveform generators for generating a digital nulling waveform, having power outside the transmission bandwidth, based on the retrieved data; and

a digital summer coupled to the waveform modules and the nulling waveform generator for generating the multi-carrier waveform based on the carrier waveforms and the nulling waveform such that the nulling waveform reduces a peak power of the multi-carrier waveform.

11. The multi-carrier waveform generator of claim 10 wherein the nulling waveform generator generates the digital nulling waveform based on data regarding predicted collisions between the digital carrier waveforms.

12. The multi-carrier waveform generator of claim 11 wherein the data regarding predicted collisions includes collision timing data.

13. The multi-carrier waveform generator of claim 11 wherein the data regarding predicted collisions includes collision duration data.

14. The multi-carrier waveform generator of claim 11 wherein the data regarding predicted collisions includes collision amplitude data.

17. The method of claim 16 further including the step of generating the digital nulling waveform based on data predicting collisions between the digital carrier waveforms.

18. The method of claim 17 further including the step of generating the digital nulling waveform based on collision timing data.

19. The method of claim 17 further including the step of generating the digital nulling waveform based on collision duration data.

20. The method of claim 17 further including the step of generating the digital nulling waveform based on collision amplitude data.

15. A multi-carrier waveform generator comprising:

a plurality of single carrier waveform modules for retrieving data from a plurality of digital carrier waveforms each having power within a transmission bandwidth;

a nulling waveform generator coupled to the single carrier waveform generators for generating a digital nulling waveform, having power outside the transmission bandwidth, based on the retrieved data, the nulling waveform generator generating a sinc waveform having power at frequencies above the transmission bandwidth and power at frequencies below the transmission bandwidth; and

a digital summer coupled to the waveform modules and the nulling waveform generator for generating the multi-carrier waveform based on the carrier waveforms and the nulling waveform such that the nulling waveform reduces a peak power of the multi-carrier waveform.

16. A method for increasing a bandwidth of a digital multi-carrier waveform based on data from a plurality of digital carrier waveforms, the method comprising the steps of:

retrieving data from the plurality of digital carrier waveforms having power within a transmission bandwidth;

generating a digital nulling waveform, based on the retrieved data, having power outside the transmission bandwidth; and

generating the digital multi-carrier waveform based on the carrier waveforms and the nulling waveform such that the nulling waveform reduces a peak power of the digital multi-carrier waveform.