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Quadrature frequency division multiplaccess signal transmission deviceand its method and base station device

An orthogonal frequency division multiple access and signal transmission technology, which is applied in the field of OFDMA signal transmission devices and can solve the problems of increased signal quality deterioration and the like

Inactive Publication Date: 2004-10-20
PANASONIC CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0024] Also, since AFC (Automatic Frequency Control) is provided only for all OFDMA frequency bands in the base station, when the frequency offset differs for each mobile station or the maximum Doppler frequency is large, the deterioration of signal quality increases

Method used

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  • Quadrature frequency division multiplaccess signal transmission deviceand its method and base station device
  • Quadrature frequency division multiplaccess signal transmission deviceand its method and base station device
  • Quadrature frequency division multiplaccess signal transmission deviceand its method and base station device

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no. 1 Embodiment

[0050] image 3 is a block diagram showing the configuration of the transmission unit in the OFDMA signal transmission device according to the first embodiment of the present invention. It should be noted that image 3 The transmission unit 100 shown is an example of a configuration in a base station when multiple access is provided to four users (four mobile stations).

[0051] The first embodiment is characterized in that, if the amount of information to be transmitted is small, subcarriers are selected and allocated at intervals of powers of 2, so that the total number of IFFT operations used in transmission can be reduced, and power consumption can be further reduced.

[0052] image 3 The transmission unit 100 shown mainly includes: S / P converters 101 to 104, rearranging device 105, IFFT device 106, P / S converter 107, D / A converter and quadrature modulator 108, transmission amplifier 109, and the transmit antenna 110 .

[0053] Figure 4 It is a subcarrier allocation...

no. 2 Embodiment

[0066] Figure 6 is a block diagram showing the configuration of the transmission unit in the OFDMA signal transmission device of the second embodiment.

[0067] The second embodiment is characterized in that when traffic is low, subcarriers are selected and allocated at fixed intervals, thereby reducing the total number of IFFT operations used in transmission to further reduce power consumption. Furthermore, it is characterized in that the output of each FFT is amplified by a different transmission amplifier in order to reduce the dynamic range of each transmission amplifier.

[0068] Figure 6 The transmission section 200 shown mainly includes: S / P / converters 201 to 204, IFFT devices 205 to 208, P / S converters 209 to 212, D / A converters and quadrature modulators 213 to 216, transmission amplifiers 217 to 220 , mixer 221 , and transmission antenna 222 .

[0069] In this configuration, the same subcarrier allocation as in the first embodiment is performed.

[0070] User A ...

no. 3 Embodiment

[0080] Figure 7 is a block diagram showing the configuration of the transmission unit in the OFDMA signal transmission device according to the third embodiment of the present invention.

[0081]The features of the third embodiment are as follows. That is, in the case of selecting and allocating subcarriers for transmission at intervals of powers of 2 in the first and second embodiments, when the amount of information to be transmitted is small, demodulation is performed by a plurality of FFT devices having a small number of subcarriers , thereby reducing the total number of FFT operations at the receiver end in order to reduce power consumption.

[0082] Figure 7 The shown receiving unit 150 mainly includes: a receiving antenna 151, a quasi-coherent detector and an A / D converter 152, S / P converters 153 to 156, FFT devices 157 to 160, P / S converters 161 to 164, and Synthesizer 165.

[0083] This structure corresponds to Figure 5 The case where the transmission end uses ...

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Abstract

In a transmission section, which performs an OFDMA signal transmission, a plurality of serial signals is converted to parallel signals by a plurality of serial / parallel converters, the plurality of converted parallel signals are rearranged at intervals of a power of 2 by a rearranging apparatus, sub-carrier assignment is performed, and inverse Fourier transform is performed with respect to the number of sub-carriers, which has been varied depending on the number of rearranged parallel signals, so as to be changed to time waveforms. The transformed parallel signals are converted to serial signals by the parallel / serial converter, the converted serial signals are converted to analog signals by D / A converter and orthogonal modulator, thereafter converting the analog signals to high frequency signals so as to be emitted. This configuration allows the amount of operations and power consumption to be reduced.

Description

[0001] This case is a divisional application of an invention patent application with an application date of May 28, 1999, an application number of 99800972.5, and an invention title of "OFDMA signal transmission device and its method". technical field [0002] The invention relates to an OFDMA (Orthogonal Frequency Division Multiple Access, Orthogonal Frequency Division Multiple Access) signal transmission device and a method thereof. Background technique [0003] In mobile communication, the problem to be solved traditionally is to overcome multipath fading and improve transmission quality. For multipath fading, multicarrier transmission is used as a measure to transmit data with good quality without reducing the symbol rate. [0004] OFDM (Orthogonal Frequency Division Multiplexing) is a multi-carrier transmission system, which sets the distance between adjacent subcarriers to 1 / symbol rate, so that the distance between subcarriers can be changed as much as possible. narr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04J11/00H04L5/02H04L27/26
CPCH04L27/2626H04L27/2628H04L5/023
Inventor 上杉充
Owner PANASONIC CORP
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