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Time-frequency synchronization method and apparatus of aviation broadband communication system based on OFDM

A wideband communication, time-frequency synchronization technology, applied in transmission system, multi-frequency code system, digital transmission system, etc., can solve problems such as narrowband interference in broadband system

Inactive Publication Date: 2017-06-13
BEIHANG UNIV
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Problems solved by technology

At the same time, the OFDM system has broadband characteristics, and the broadband system is more likely to introduce narrowband interference

Method used

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  • Time-frequency synchronization method and apparatus of aviation broadband communication system based on OFDM
  • Time-frequency synchronization method and apparatus of aviation broadband communication system based on OFDM
  • Time-frequency synchronization method and apparatus of aviation broadband communication system based on OFDM

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Embodiment Construction

[0081] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0082] At first, the system model of the aviation broadband communication system based on OFDM of the present invention is described:

[0083] The baseband signal r generated by the transmitting end of the OFDM ground-air broadband communication system is as follows:

[0084]

[0085]

[0086] Based on the WSSUS channel, the general model of broadband aviation wireless channel is:

[0087]

[0088] In the formula, t and τ are specific moments and tim...

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Abstract

The embodiment of the invention provides a time-frequency synchronization method and apparatus of an aviation broadband communication system based on OFDM. The problem that the estimation range of a typical Moose estimation method is insufficient is solved by an integral multiple frequency offset estimation scheme of firstly performing differential correlation based on subcarriers and performing correlation operation with a pre-stored sequence to find an integral multiple frequency offset fold. In view of time synchronization with large frequency offset, although the typical SAC method is not sensitive to the frequency offset, the erroneous judgment probability of the method is relatively large. According to the time-frequency synchronization method and apparatus provided by the invention, a rough synchronization position is found by SAC at first, frequency offset compensation and sliding correlation operation are carried out on the pre-stored sequence to find an accurate synchronization position corresponding to a maximum related peak position. The time synchronization performance is greatly improved.

Description

technical field [0001] The present invention relates to the technical field of an OFDM-based aviation broadband communication system, in particular to a time-frequency synchronization method and device for an OFDM-based aviation broadband communication system. Background technique [0002] Under the aviation channel, the flight speed of the aircraft can reach up to 1000km / h. For the aeronautical broadband system, a large Doppler frequency shift will be generated, and the modulation performance of Orthogonal Frequency Division Multiplexing (OFDM, Orthogonal Frequency Division Multiplexing) is just very sensitive to the Doppler frequency shift. At the same time, the OFDM system has broadband characteristics, and the broadband system is more likely to introduce narrowband interference. [0003] In a high-speed motion environment, accurate time synchronization and frequency offset estimation, namely frequency synchronization, are the prerequisites for an OFDM-based aviation bro...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26
CPCH04L27/2655H04L27/2657H04L27/2659H04L27/266
Inventor 王鑫张晓林
Owner BEIHANG UNIV
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