Orthogonal frequency division multiplex receiving system for symbol timing synchronization and its method

A receiving method and orthogonal frequency division technology, applied in the field of OFDM receiving systems, can solve the problems of performance degradation of the OFDM receiving system, uncertainty of the starting point of symbols by a window timing controller, etc.

Inactive Publication Date: 2009-06-03
SAMSUNG ELECTRONICS CO LTD
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Problems solved by technology

[0004] However, when setting the FFT window period, such as figure 1 As shown in (a), in a pre-ghost channel environment with multipath that causes inter-symbol interference (ISI) to occur between the end of one symbol and a part of the next symbol, the window The timing controller is not sure of the correct symbol origin, as in figure 1 as shown in (b)
This ISI causes performance degradation of the OFDM receiving system

Method used

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  • Orthogonal frequency division multiplex receiving system for symbol timing synchronization and its method
  • Orthogonal frequency division multiplex receiving system for symbol timing synchronization and its method
  • Orthogonal frequency division multiplex receiving system for symbol timing synchronization and its method

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Embodiment Construction

[0017] Embodiments of the present invention will be described below with reference to the accompanying drawings.

[0018] 2 is a general block diagram of an Orthogonal Frequency Division Multiplexing (OFDM) receiving system that performs symbol timing synchronization in accordance with the present invention. The OFDM receiving system of FIG. 2 includes an analog / digital converter (ADC) 210, a rough symbol synchronization extractor 220, a fast Fourier transform (FFT) window controller 230, an FFT operation unit 240, and a scattered pilot pattern detector 250 , a scattered pilot extractor 260, a symbol timing offset estimator 270, and a digital phase locked loop (DPLL) 280.

[0019] ADC 210 converts the OFDM signal into digital complex samples with a sampling rate of 9.14 MHz.

[0020] A coarse symbol sync extractor 220 extracts a coarse symbol start from the received digital complex samples.

[0021] The FFT window controller 230 uses the coarse symbol synchronization signal ...

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Abstract

An orthogonal frequency division multiplex (OFDM) receiving system for changing a fast Fourier transform (FFT) window period using a guard interval, and a method for the same are provided. The method includes extracting scattered pilots, which are inserted into a symbol at intervals of predetermined samples, from a received OFDM signal, estimating a symbol timing offset using the extracted scattered pilots and setting a symbol timing synchronization point in the data transmission interval, and adding samples in a predetermined interval in the data transmission interval to samples in an interval obtained by subtracting a predetermined length from the useful symbol interval starting from the symbol timing synchronization point and performing FFT with respect to the result of addition. Accordingly, symbol timing synchronization and channel equalization can be accurately performed without having ISI even when a symbol start point is not correctly decided under a multi-channel (or a Rayleigh channel) or a pre-ghost channel environment.

Description

technical field [0001] The present invention relates to an Orthogonal Frequency Division Multiplexing (OFDM) receiving system, in particular to an OFDM receiving system and method for changing the period of a Fast Fourier Transform (FFT) window by using a guard interval. Background technique [0002] Generally, an OFDM transmission system uses Fast Fourier Transform (FFT) to transmit information via subcarriers, and adds a guard interval to the front of useful symbols in order to reduce the impact of multipath. The OFDM receiving system finds the boundary between the guard interval and the useful symbol interval in the received OFDM signal, and performs FFT window timing synchronization so that FFT is performed only on the useful symbols. For this reason, the OFDM receiving system uses the similarity between the guard interval and useful symbols to roughly calculate the FFT interval. [0003] figure 1 It is a conceptual diagram of symbol timing synchronization in a traditi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04J11/00H04L7/00H04L7/08H04L25/03H04L27/26H04N7/015
CPCH04L25/03006H04L27/2662H04L27/261H04L27/2607H04L27/2679H04N7/015
Inventor 金正振韩东锡
Owner SAMSUNG ELECTRONICS CO LTD
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