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CDMA receiving apparatus

A receiving device and direct technology, applied in radio transmission systems, electrical components, transmission systems, etc., can solve the problems of large circuit scale and large data processing volume

Inactive Publication Date: 2003-04-30
FUJITSU LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when performing despreading by complex multiplication, since a multiplier is required, the circuit scale is large, and / or the amount of data processing for calculation is large

Method used

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  • CDMA receiving apparatus

Examples

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Embodiment Construction

[0048] Figure 5 A general configuration of a CDMA receiving apparatus showing the first embodiment of the present invention is shown. The configuration includes an antenna 1, a high-frequency amplifier 2, a band-pass filter 3, demodulators 4, 5, a carrier generation section 6, a phase shifter (π / 2) 7 for phase-shifting an input signal by π / 2, A-D Converters (A-D) 8, 9, despreading section 10, fading compensation section 11, and decision and output section 12. The despreading section includes a selector section 13 .

[0049] The configuration and function of the parts from antenna 1 to A-D converter 8, 9 are related to figure 1 Those of the related art shown are similar, so repeated explanations will be omitted. The despreading section 10 including the selector section 13 selects a signal from the demodulated in-phase signal and the demodulated quadrature signal, and the inverted in-phase signal and the inverted quadrature signal, wherein the demodulated signal is Inverted...

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PUM

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Abstract

A CDMA receiving apparatus receives a direct sequence CDMA signal produced through QPSK spreading modulation, performs coherent detection of the direct sequence CDMA signal, and despreads the signals, obtained through the coherent detection, through a despreading portion (10). The despreading portion comprises a selector portion (13). The selector portion selects signals as a demodulated and despread inphase output signal and a demodulated and despread quadrature output signal, in accordance with despreading codes, from demodulated in-phase and quadrature signals obtained through the coherent detection, and an inverted inphase and quadrature signals obtained as a result of the signs of the demodulated inphase and quadrature signals being inverted.

Description

technical field [0001] The invention relates to a CDMA (Code Division Multiple Access) receiving device, which receives and demodulates a direct sequence CDMA signal generated by QPSK (Quadrature Phase Shift Keying) spread spectrum modulation. Background technique [0002] In the DS-CDMA (Direct Sequence CDMA) method, the BPSK (Binary Phase Shift Keying) method, or the QPSK method is selected as the modulation method. When the QPSK method is used, the in-phase signal and the quadrature signal are spread-modulated with different spreading codes and combined in the transmitting device. The signal thus generated is transmitted by the transmitting device. The CDMA receiving device demodulates the received signal into an in-phase signal and a quadrature signal, and performs despreading processing on the in-phase signal and the quadrature signal with a despreading code, where the despreading code is generated synchronously with the spreading code. There is a demand to reduce the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/22H04B1/16H04B1/707H04B1/7093
CPCH04B2201/70707H04B1/707
Inventor 浜田一大石泰之福政英伸松山幸二
Owner FUJITSU LTD