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A Time-Frequency Synchronization Method for Doppler Wireless Communication Based on Ofdm

A time-frequency synchronization and wireless communication technology, applied in wireless communication, synchronization devices, multi-frequency code systems, etc., can solve problems such as overrunning, fast satellite movement, multi-path channel fading, etc., to achieve correct demodulation and solve real-time effect of change

Active Publication Date: 2022-04-01
NO 54 INST OF CHINA ELECTRONICS SCI & TECH GRP
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Problems solved by technology

Especially in the LEO low-orbit satellite communication scenario, the satellite moves fast, there is a large-scale Doppler frequency shift between the satellite and the ground, and multipath channel fading, and the general Doppler frequency shift is much larger than the subcarrier spacing of the OFDM system , which exceeds the current frequency offset estimation capability of the terrestrial 5G standard, which makes the carrier and symbol synchronization at the two ends of the satellite and the ground face a big problem
Therefore, time-frequency synchronization is the primary problem to be solved in the wireless communication system under the condition of Doppler frequency shift, especially the satellite communication system integrated with 5G, which restricts the effective application of 5G OFDM technology in satellite communication

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  • A Time-Frequency Synchronization Method for Doppler Wireless Communication Based on Ofdm
  • A Time-Frequency Synchronization Method for Doppler Wireless Communication Based on Ofdm
  • A Time-Frequency Synchronization Method for Doppler Wireless Communication Based on Ofdm

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Embodiment Construction

[0034] The present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments.

[0035] A method for time-frequency synchronization of Doppler wireless communication based on OFDM, applied to a receiving end of a wireless communication system, wherein the receiving end stores the same primary synchronization symbol and data symbol frequency domain pilot as the sending end, comprising the following steps :

[0036] (1) Receive OFDM transmission signals including preamble symbols, primary synchronization symbols and data symbols, use preamble symbols to perform sliding correlation calculations, detect correlation peaks, and perform rough symbol timing synchronization;

[0037] (2) Use the preamble symbol to perform rough estimation of the Doppler frequency offset, and realize the joint estimation of the integer multiple frequency offset and the fractional multiple frequency offset;

[0038] (3) Utilize the estimation result...

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Abstract

The invention discloses an OFDM-based Doppler wireless communication time-frequency synchronization method, which belongs to the technical field of wireless communication. It includes the following steps: using preamble symbols to realize coarse timing synchronization of symbols, using preamble symbols to realize rough estimation of Doppler frequency offset, using frequency offset estimated values ​​to perform preliminary frequency offset compensation and correction on symbols, and using PSS symbols after preliminary frequency offset compensation and Correlation calculations are performed on locally known PSS symbols to achieve precise symbol timing synchronization, and FFT operations are performed on data symbols to realize signal time-frequency domain conversion. Using the received data symbol internal frequency domain pilot and locally known pilot, through a The first-order filter frequency-locked loop realizes residual frequency offset estimation and real-time compensation. The present invention can realize the time and frequency synchronization of the wireless communication system in the OFDM-based multi-Puller scenario when neither the user terminal nor the gateway station has ephemeris, and can meet the multi-Puller and multipath conditions of future broadband high-throughput satellites Lower synchronous demodulation requirements.

Description

technical field [0001] The invention relates to the technical field of wireless communication, in particular to an OFDM-based Doppler wireless communication time-frequency synchronization method. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) technology is widely used in terrestrial wireless cellular communication systems due to its strong anti-multipath ability and high spectrum efficiency, especially the NR Release15 of the fifth generation mobile communication system (5G). Non-Standalone Networking (NSA) and Release 16 Standalone Networking (SA) standards still use OFDM waveforms as the core waveforms for physical layer transmission. However, the receiving end of OFDM technology is sensitive to carrier frequency deviation (CFO) and symbol timing deviation that cause inter-subcarrier interference (ICI), which restricts the implementation of OFDM technology in wireless communication systems under large dynamic Doppler conditions, especially ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/26H04W56/00
CPCH04L27/2663H04L27/2665H04W56/005
Inventor 刘允宋瑞良宋志群卢宁宁李捷
Owner NO 54 INST OF CHINA ELECTRONICS SCI & TECH GRP
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