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

Radio communication system, radio transmitter and radio receiver

A wireless communication system and wireless transmission technology, applied in the field of wireless receivers and wireless communication systems, can solve problems such as the destruction of orthogonality between subcarriers, the degradation of receiving characteristics, and the increase in interference between symbols, and achieve good communication and suppression Effect of Peak-to-Average Power Ratio

Inactive Publication Date: 2005-11-09
NTT DOCOMO INC
View PDF0 Cites 4 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In the method of clipping the undesired peak power value, the orthogonality between the subcarriers is destroyed, and the intersymbol interference increases, deteriorating the reception characteristics

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
  • Radio communication system, radio transmitter and radio receiver
  • Radio communication system, radio transmitter and radio receiver
  • Radio communication system, radio transmitter and radio receiver

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Figure 5 A block diagram showing an OFDM radio transmitter according to an embodiment of the present invention. The wireless transmitter has: a signal generation unit 502, a serial-parallel conversion unit (S / P) 504, an inverse fast Fourier transform unit (IFFT unit) 506, a parallel-serial conversion unit (P / S) 508, a guard interval adding unit (GI adding part) 510, antenna 512. The wireless transmitter has a peak extraction unit 514, a serial-to-parallel conversion unit (S / P) 516, a fast Fourier transform unit (FFT unit) 518, an amplitude control unit 520, and a plurality of subtraction units 522-1 to Ns (where Ns is a number of carriers).

[0035] The signal generator 502 receives a signal indicating transmission information, and performs processing such as error correction coding, interleaving, and symbol mapping.

[0036] The serial-to-parallel conversion units 504 and 516 convert a series of input signal sequences into a plurality of parallel signals.

[0037]...

Embodiment 2

[0044] Image 6 A block diagram showing an OFDM radio transmitter according to an embodiment of the present invention. The wireless transmitter has: a signal generation unit 602, a serial-parallel conversion unit (S / P) 604, a pilot signal insertion unit 605, a pilot signal generation unit 607, an inverse fast Fourier transform unit (IFFT unit) 606, and a parallel-serial conversion unit (P / S) 608 , guard interval adding unit (GI adding unit) 610 , and antenna 612 . The wireless transmitter has: a peak extraction unit 614, a serial-to-parallel conversion unit (S / P) 616, a fast Fourier transform unit (FFT unit) 618, a power control unit 620, and a plurality of multiplication units 622-1 to Ns (where Ns is number of subcarriers).

[0045] The signal generator 602 receives a signal indicating transmission information, and performs processing such as error correction coding, interleaving, and symbol mapping.

[0046] The serial-to-parallel conversion units 604 and 616 convert a s...

Embodiment 3

[0066] Hereinafter, an example of inserting several pilot signals will be described. exist Image 6 The pilot signal inserted into the transmission signal by the pilot signal insertion unit 605 is used for estimating the channel variation (or attenuation) in the frequency direction and time direction in the receiver. In addition, generally, in a low-speed mobile communication environment, the channel variation in the frequency direction is larger than the channel variation in the time direction. Therefore, from the viewpoint of accurately investigating channel fluctuations, it is preferable to insert pilot signals into all subcarriers. On the other hand, if a plurality of pilot signals are inserted into the transmission signal, correspondingly, fewer data signals are transmitted. Therefore, from the viewpoint of data transmission, it is desirable to have fewer pilot signals.

[0067]In a modulation scheme such as phase shift keying (PSK), the magnitude of the amplitude is k...

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

A radio transmitter adopting the OFDM scheme is disclosed. The radio transmitter includes an amplitude measuring part for measuring the amplitude of a transmission signal on which inverse Fourier transform has been performed; a power control part for outputting, based on the result of the measurement, control signals each for adjusting the amplitude of a signal on which inverse Fourier transform has not been performed, each signal corresponding to one of plural sub-carriers; and multiple multiplying parts each for multiplying the amplitude of the signal by a multiplying number indicated by the control signal. The power control part outputs the control signal based on a product of a signal pf(n) obtained by performing Fourier transform on an output of the amplitude measuring part and the signal sf(n).

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to a wireless communication system, a wireless transmitter, and a wireless receiver adopting an Orthogonal Frequency Division Multiplexing (OFDM) method. Background technique [0002] The OFDM system that has attracted attention in this technical field is a technology that can realize good signal transmission even in a multipath propagation environment or the like by arranging a plurality of carriers (subcarriers) at mutually orthogonal frequency intervals. In the transmitter of this method, such as figure 1 As shown, the signal generated in the signal generation part according to the transmission information is converted into a plurality of parallel signal sequences by the serial-to-parallel conversion part (S / P), and processed by the inverse fast Fourier transform part (IFFT part). Convert it into a single signal sequence in the P / S section, add a guard interval (g...

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): H04J11/00H04B1/04H04L27/26
CPCH04L27/2614
Inventor 藤井启正沈纪恽浅井孝浩吉野仁
Owner NTT DOCOMO INC