Unlock instant, AI-driven research and patent intelligence for your innovation.

OFDM modulated wave output device and distortion compensation method

An output device and distortion compensation technology, which is applied in the modulation carrier system, components of amplifying devices, improving amplifiers to reduce nonlinear distortion, etc. It can solve problems such as signal quality degradation and peak power suppression

Inactive Publication Date: 2009-09-23
NEC CORP
View PDF3 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the partial transmit sequence technique can reduce out-of-band distortion by reducing peak power, it has a limit on the peak power that can be reduced by phase weighting, so it is impossible to suppress the peak power in its absolute value
[0015] Within the LCP-COFDM / partially transmitted sequence technique, there is a flaw: while the characteristic improvements through both described techniques can be achieved, the transmission of side information is also required
In the technique of improving the linearity when generating peak power, although the linearity can be improved by temporarily applying a higher voltage or a larger current, the linearity improvement of the power amplifier achieved in this way is accompanied by small-signal gain of the amplifier, delay time characteristics, A change in the non-linear characteristic (AM (Amplitude Modulation)-AM characteristic or AM-PM (Phase Modulation) characteristic), thus causing a degradation of signal quality when dealing with higher peak powers

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • OFDM modulated wave output device and distortion compensation method
  • OFDM modulated wave output device and distortion compensation method
  • OFDM modulated wave output device and distortion compensation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0024] Hereinafter, an exemplary embodiment of the present invention will be described in detail with reference to the accompanying drawings. figure 1 The configuration of the OFDM modulated wave output device according to the embodiment of the present invention is shown. The OFDM modulated wave output device 100 includes a serial / parallel conversion circuit (S-P conversion circuit) 101, an IFFT circuit (inverse fast Fourier transform circuit) 102 and 105, GI (guard interval) increasing circuits 103 and 106, weighted D / A Converters 104 and 107, quadrature modulation circuit 112, power amplifier 113, amplitude extraction circuit 108, GI counterpart addition circuit 109, sustained peak control circuit 110, weighted D / A (digital / analog) converter 111, power amplifier control circuit 114 , power amplifier characteristic compensation data table 115 and compensation value selection control circuit 116 .

[0025] The S-P conversion circuit 101 converts an input serial data string in...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

Provided is an OFDM (Orthogonal Frequency Division Multiplex) modulated wave output device. An amplitude extraction unit (108) extracts an amplitude of the OFDM modulated wave. If the extracted amplitude exceeds a predetermined amplitude, a power amplifier control unit (114) sets such a power supply to a power amplifier (113) that amplifies an OFDM modulated wave so that the power exceeds a rated power, thereby increasing a saturation point in the power amplifier. When the power amplifier control unit has increased the saturation point of the power amplifier, a compensation value selection control unit (116) compensates nonlinear characteristic of the power amplifier.

Description

technical field [0001] The present invention relates to an OFDM modulated wave output device and a distortion compensation method, in particular to an OFDM modulated wave output device generating an OFDM modulated wave and a distortion compensation method used in such an OFDM modulated wave output device. Background technique [0002] In OFDM (Orthogonal Frequency Division Multiplexing) technology, the frequency spectrum of the signal used therein is close to rectangular, thereby obtaining higher frequency usage efficiency. In addition, OFDM technology has a large impedance to delayed waves because it can make the symbol length longer than a single carrier, and the addition of a guard interval makes OFDM technology stronger in a multipath environment if used. On the other hand, in an OFDM technique that performs multicarrier transmission in which a large number of subcarriers exist, if subcarriers each have peaks overlapping with each other, an OFDM signal has a large peak p...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H04J11/00H03F1/32H04B1/04H04J1/00
CPCH04L27/366H04L27/2626H03F1/3241H04B1/0475H04L27/361H04B1/0483H03F1/0211H04B2001/0441H03F1/3223H03F3/24H04B1/62H04L27/2627
Inventor 藤本芳宣
Owner NEC CORP