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Method for detecting time offset and frequency offset of OFDM symbol

A symbol, frequency offset technology, applied in the field of communication, can solve the problems of low efficiency and high complexity

Active Publication Date: 2010-03-17
SUZHOU NG NETWORKS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0007] The present invention aims to provide a method for detecting OFDM symbol time offset and frequency offset, which can solve the problems of high complexity and low efficiency in the prior art for detecting OFDM symbol time offset and frequency offset

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  • Method for detecting time offset and frequency offset of OFDM symbol
  • Method for detecting time offset and frequency offset of OFDM symbol
  • Method for detecting time offset and frequency offset of OFDM symbol

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Embodiment Construction

[0018] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0019] figure 1 A block diagram of an OFDM receiver with two receive (Rx) antennas according to one embodiment of the present invention is shown. The so-called Begin of Frame (BOF) and carrier frequency offset (Carrier Frequency Offset, CFO) can be calculated by completing coarse synchronization. At the same time, the Begin of Symbol (BOS) of OFDM also needs to be determined. Here, unless otherwise indicated, an OFDM symbol includes a CP (CyclicPrefix, cyclic prefix) part in the time domain. Therefore, BOS is also the starting point of CP. Once the BOS is determined, the CP can be properly deleted. Through DFT (Discrete Fourier Transformation, discrete Fourier transform), the signal is converted from the time domain to the frequency domain. In this way, channel estimation and equalization can be easily implemented in the frequen...

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Abstract

The invention discloses a method for detecting time offset and frequency offset of an OFDM symbol. The method comprises the following steps: calculating a hysteresis autocorrelation function of data sample points of a received signal; determining the time offset amount of the data sample points according to the hysteresis autocorrelation function; and calculating estimated values theta^ and epsilon^ of the time offset theta and the frequency offset epsilon of the data sample point accoridng to the time offset amount.

Description

technical field [0001] The present invention relates to the communication field, in particular to a method for detecting time offset and frequency offset of OFDM symbols. Background technique [0002] In a wireless cellular system, a user equipment (User Equipment, UE) will try to connect to a network, and synchronization is the first task. As we all know, OFDM (Orthogonal Frequency-Division Multiplexing, Orthogonal Frequency Division Multiple Access) system is very sensitive to frequency offset and time offset. Here, frequency offset and time offset refer to the deviation in frequency and time between the received signal and the local reference signal used for signal demodulation. Frequency offset and time offset may be caused by the oscillator mismatch between the transmitter and receiver, and also by the Doppler effect, multipath propagation, etc. Frequency offset can destroy the orthogonality between subcarriers and generate inter-carrier interference (ICI) and multipl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L25/03
Inventor 许文黄学民
Owner SUZHOU NG NETWORKS