Large frequency offset estimation and PN (Pseudorandom Noise) mode detection method and system

Abstract

The invention discloses a large frequency offset estimation and PN (Pseudorandom Noise) mode detection method and system suitable for a DTMB (Digital Terrestrial Multimedia Broadcast) receiver system. The method comprises the following steps: storing a certain number of received data; realizing correlation operation by using FFT / IFFT (Fast Fourier Transform / Inverse Fast Fourier Transform); performing frequency sweeping to obtain a frequency point corresponding to a maximum correlation value and calculating system frequency offset; trying in different PN modes, wherein a PN mode corresponding to the maximum correlation value is a system PN mode; shifting FFT output data and performing frequency sweeping control in an implementation process. A correlator is replaced by using the FFT / IFFT, thereby greatly saving the hardware cost; storage data are operated, thereby increasing the operation speed; moreover, a method combining frequency sweeping and PN mode trial is adopted, thereby eliminating the limits of channels and other factors and realizing independence and high robustness.

Description

technical field [0001] The invention relates to the field of wireless communication data processing, and mainly relates to a large frequency offset estimation and PN mode detection method for a DTMB receiver system. Background technique [0002] Among the digital TV terrestrial, cable, satellite and many other transmission methods, the digital TV transmission system is the most complicated, and has attracted much attention because of its highest technical requirements and wide audience. Of course, the standardization of the ground system is also very important. At present, there are three international standards for terrestrial digital TV broadcast transmission approved by ITU, namely, American Advanced Television Systems Committee (ATSC), European Digital Video Terrestrial Broadcasting (DVB-T) and Japanese Terrestrial Integrated Services Digital Broadcasting (ISDB-T). In 1999, my country set up digital TV research and development and industrialization and established an in...

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Problems solved by technology

[0009] (1) Use sliding correlation or differential correlation or segmental correlation to resist frequency offset for PN mode detection, and then use the corresponding frequency offset estimation algorithm to remove frequency offset; however, this method is mainly sensitive to channels and will fail in complex channels, and The range of frequency offset estimation is limited, and the error is also large

[0010] (2) Use frequency sweep and try three PN modes in turn. Although this method has better performance and controllable errors, it takes a long time to capture, and it needs to be compromised between the frequency offset estimation range, estimation error, and capture time. middle processing

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