A method for improving the time domain synchronization interference of direct series spread spectrum OFDM

A technique of direct-sequence spread spectrum and time-domain synchronization, applied in multi-frequency code systems, code-division multiplexing systems, electrical components, etc., can solve problems such as mutual interference of different spread-spectrum codes, improve mutual interference, improve The effect of the call effect

Inactive Publication Date: 2007-07-11
FOUNDER BROADBAND NETWORK SERVICE
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Problems solved by technology

[0009] The purpose of the present invention is to aim at the defect of prior art scheme, provide a kind of method that can improve the mutual interference between different spread spectrum codes caused by not strict synchronization in time domain in direct sequence spread spectrum OFDM

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  • A method for improving the time domain synchronization interference of direct series spread spectrum OFDM
  • A method for improving the time domain synchronization interference of direct series spread spectrum OFDM

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[0029] The technical solution of the present invention will be described in detail below with reference to FIG. 2 to FIG. 4 . Before explaining the method described in the present invention in detail, first briefly introduce the reasons and solutions for the mutual interference between different spreading codes caused by not strictly synchronizing in the time domain in direct sequence spread spectrum OFDM.

[0030] For the simplicity of problem analysis, the influence of noise is not considered below.

[0031] Let a spreading code at the transmitter be C=(c 0 , c 1 , c 2 ,...,c N-1 ), c i ∈(1, -1), and the FFT point N of the OFDM system maps the kth chip of the spreading code to the kth subcarrier of the OFDM system, then the signal at the sending end is

[0032] T=(t 0 , t 1 , t 2 ,...,t N-1 , t 0 , t 1 , t 2 ,...,t L-1 )

[0033] in

[0034] t n =(1 / sqrt(N))∑ N-1 0 c k e jwnk , w=2π / N.

[0035] At the receiving end, if the time synchronization result is ...

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Abstract

This invention relates to method to improve direct sequence extensive frequency OFDM time zone simultaneous interference, which comprises the following steps: firstly determining signal channel zone laser response gravity for data correction through rapid Fourier exchange accordingly. The signal channel time zone laser response method comprises the following steps: firstly sending guide frequency character in send end and processing rapid Fourier exchange at receive end; then removing modulation data to estimate signal channel time zone laser response through conversion of direction.

Description

technical field [0001] The invention relates to a method for improving the mutual interference between different spreading codes caused by not strict synchronization in the time domain in direct sequence spread spectrum OFDM (Orthogonal Frequency Division Multiplexing), which belongs to mobile communication technology field. Background technique [0002] Direct-sequence spread spectrum OFDM is a modulation method that combines direct-sequence spread spectrum modulation and OFDM modulation. This modulation method can achieve the purpose of combining CDMA and OFDM. The signal processing of direct sequence spread spectrum OFDM at the receiving end can also be divided into two parts: OFDM signal processing and CDMA signal processing. The OFDM signal processing part includes time and frequency synchronization, determining the OFDM window position and FFT calculation. The OFDM signal processing in this part can be completely the same as the signal processing of a general OFDM sys...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L25/02H04J13/04H04B1/7097
Inventor 康良川
Owner FOUNDER BROADBAND NETWORK SERVICE
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