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Doppler frequency offset estimation method and system under high-speed rail environment

A Doppler frequency offset and frequency offset estimation technology, which is applied in the field of Doppler frequency offset estimation in the high-speed rail environment, can solve the problems of high complexity and poor performance, and achieve the effects of high precision, low cost, and simple system structure

Inactive Publication Date: 2015-10-28
HANGZHOU XIANGSHENG COMM
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Problems solved by technology

The existing frequency offset estimation algorithms based on the pilot information and CP statistical characteristics of OFDM system all use the phase change information of the received signal, or use the known pilot and decision data, or use the repeatability of the data to extract the frequency offset value, however, the performance of the frequency offset estimation algorithm using CP is the worst, and the performance of the algorithm using known pilots is better, but its complexity is high

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  • Doppler frequency offset estimation method and system under high-speed rail environment
  • Doppler frequency offset estimation method and system under high-speed rail environment
  • Doppler frequency offset estimation method and system under high-speed rail environment

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Embodiment 1

[0051] There are multipath propagation and Doppler effect in the wireless channel. The OFDMA technology used in LTE downlink has a strong ability to resist wireless fading channels, but it is very sensitive to frequency and phase offset. The Doppler frequency shift caused by high-speed movement will destroy the orthogonality between OFDM subcarriers, resulting in inter-carrier interference (ICI). In this embodiment, the frequency offset estimation technology for the LTE downlink is studied. According to the characteristics of the Rice channel of the high-speed railway, the influence of the frequency offset on the received signal is transferred to the influence of the frequency offset on the channel, and the channel information is extracted to obtain Perform frequency offset estimation. The method first performs time-domain channel estimation, then separates the Rice LOS paths of the time-domain channel response, and finally uses the extracted channel LOS paths to perform corre...

Embodiment 2

[0093] At present, using the existing cellular public mobile telecommunication system (UMTS) is a commonly used high-speed railway broadband wireless access network architecture, which uses a baseband processing unit to control multiple remote radio remote units (RRU) Increase the cell radius and reduce the number of cell switching. Through remote radio technology, the coverage of each baseband processing unit (BBU) cell can be expanded to 40-70km, reducing the number of cell handovers. However, this solution still needs to lay a large number of expensive base station equipment along the railway line, and the cost is relatively high. Since high-speed trains run far apart, the spectrum resources and processing capabilities of these devices are idle when no train is within their coverage area, resulting in a great waste. In addition, the RRU is used to estimate the Doppler frequency offset, because the Doppler frequency offset estimation algorithm is usually relatively complica...

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Abstract

The invention provides a Doppler frequency offset estimation method under a high-speed rail environment. The method comprises the following steps: step 10, acquiring time domain channel estimation; step 20, separating a channel estimation value containing a LOS path; step 30, performing frequency offset estimation. The invention further provides a Doppler frequency offset estimation system under the high-speed rail environment. The method provided by the invention is low in operational complexity and high in precision, capable of effectively eliminating frequency offset jump, and releasing the load of a radio frequency remote unit; the system is simple in structure and low in cost.

Description

technical field [0001] The present invention relates to the field of high-speed rail communication services, and more particularly, to a method and system for estimating Doppler frequency offset in a high-speed rail environment. Background technique [0002] As an important means of transportation in modern times, high-speed trains are closely related to people's lives. At present, my country's high-speed railway is being built and put into operation on a large scale. The train speed can reach 350km / h, and the operating speed can reach 500km / h or even higher in the future, which makes people's life more convenient and efficient. During the several hours of riding a high-speed train, passengers need to be in a real-time "information online" state. The high-speed train cannot become an "information island", so passengers must be able to keep in touch with the outside world in real time through wireless terminals such as mobile phones and notebooks. This requires Under high-sp...

Claims

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Application Information

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IPC IPC(8): H04L25/02H04L25/03H04L27/26
Inventor 杨炜锋
Owner HANGZHOU XIANGSHENG COMM
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