System and method for reducing peak-to-average power ratio for multi-carrier communication systems

• US 7,639,747 B2
• Filed: 10/23/2003
• Issued: 12/29/2009
• Est. Priority Date: 10/23/2003
• Status: Active Grant

• Current Assignee: Smartsky Networks Llc
• Original Assignee: Harris Corporation (L3Harris Technologies, Inc.)
• Inventors: Richards, Charles W., Kolar, Ray J., Moffatt, Christopher Douglas
• Primary Examiner(s): Lugo, David B
• Application Number:
  US10/690,613
• Publication Number:
  US 20050089116A1
• Time in Patent Office: 2,259 Days
• Field of Search: 375/295, 375/286, 375/259, 375/260
• US Class Current: 375/260
• CPC Class Codes: H04L 27/2614 Peak power aspects

Abstract

The present disclosure presents a predictive signal producing method that effectively levels transmitter output power in a multi-carrier communication system and results in approaching amplifier performance normally associated with constant carrier waveforms. Embodiments of the disclosed solution offers >10 dB reduction in the peak-to-average power required to support the transmission of, for example, orthogonal frequency division modulation (“OFDM”) modulation techniques. Embodiments of the novel system and method maximize peak-to-average power ratio (“PAPR”) reduction with selective mapping and soft clipping, which may include filtering, combined. This novel approach also minimizes overhead, bit error rate, retransmissions, and increases latency as well as implementing processing cycles with a number of iterations. The disclosed system and method improves the total system DC power efficiency and provides an optimal solution for PAPR reduction in multi-carrier communication systems such as, for example, OFDM.

Claims

1. A method for reducing the peak-to-average power ratio of a communication signal comprising the steps of:

(a) sequencing a data signal according to a data vector to thereby create a sequenced data signal;

(b) modulating a first plurality of carrier waves at a second plurality of frequencies with said sequenced data signal to thereby create a modulated signal;

(c) measuring the peak-to-average power ratio of the modulated signal;

(d) comparing said power ratio with a predetermined threshold;

(e) if said power ratio exceeds said predetermined threshold, sequencing said data signal according to a data vector different from previous data vectors to thereby create a sequenced data signal different from previous sequenced data signals and repeating steps (b)-(e) until said power ratio does not exceed said predetermined threshold;

(f) if said power ratio does not exceed said predetermined threshold, appending to the modulated signal a data map signal associated with the data vector for which said power ratio does not exceed said predetermined threshold to thereby create an appended signal;

(g) sampling said appended signal;

(h) reducing amplitude of said samples which exceed a predetermined range to thereby create a reduced amplitude signal;

(i) filtering said reduced amplitude signal to thereby create said communication signal with a reduced peak-to-average power ratio.

2. The method to claim 1, further comprising the step of reducing amplitude of samples adjacent to the samples exceeding the threshold.