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A Method for Uplink Sampling Frequency Offset Estimation and Compensation in LEO Satellite Multi-Carrier Communication System

A technology of multi-carrier communication and sampling frequency offset, applied in multi-carrier systems, modulated carrier systems, multi-frequency code systems, etc., can solve problems such as performance loss, achieve a high demodulated signal-to-noise ratio range, and reduce sampling frequency offset. The effect of estimating complexity

Active Publication Date: 2022-05-27
上海众睿通信科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In order to solve the problem of low-orbit satellite multi-carrier communication system, sampling frequency offset brings performance loss to reception, the present invention proposes a method for estimating and compensating uplink sampling frequency offset of low-orbit satellite multi-carrier communication system

Method used

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  • A Method for Uplink Sampling Frequency Offset Estimation and Compensation in LEO Satellite Multi-Carrier Communication System
  • A Method for Uplink Sampling Frequency Offset Estimation and Compensation in LEO Satellite Multi-Carrier Communication System
  • A Method for Uplink Sampling Frequency Offset Estimation and Compensation in LEO Satellite Multi-Carrier Communication System

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specific example

[0038] see image 3, a specific example of the uplink sampling frequency offset estimation and compensation method is as follows:

[0039] Step 1: The user terminal estimates the uplink pre-compensation sampling frequency offset according to the downlink sampling frequency offset estimation result, and performs the first compensation for the uplink signal transmitted by the user terminal according to the calculated uplink pre-compensation sampling frequency offset estimation value; ground, record the user terminal downsampling frequency offset estimation result as The down sampling frequency is f s,downlink , the upstream sampling frequency is f s,uplink . Then the estimated value f of the upstream pre-compensation sampling frequency offset pre,uplink for:

[0040]

[0041] Step 2: The user terminal uses the uplink reference signal to estimate the uplink residual sampling frequency offset, and uses the estimated value of the uplink residual sampling frequency offset t...

Embodiment 1

[0056] Assume that the altitude of the satellite is 1175km, and the speed of the satellite is 7.2km / s. The elevation angle of the gateway to the satellite is 5°, the maximum elevation angle between the public reference point of the user link and the satellite is 30°, the width of the satellite beam is 3°, and the uplink and downlink sampling frequencies are f. s Both are 491.52MHz. Considering that the terminal is located at the center of the beam coverage (cell reference point), the Doppler sampling frequency offset calculation formula It can be calculated that in the terminal-satellite-gateway link, the Doppler sampling frequency offset of both the uplink and the downlink is 14.5kHz. Assuming that the sampling crystal accuracy of the terminal and the gateway station are both 100ppb, in the worst case, the total sampling frequency offset of the downlink is about 14.4kHz, and the total sampling frequency offset of the uplink is about 14.6kHz.

[0057] Assuming that the down...

Embodiment 2

[0059] Assume that the terminal-satellite-signal gateway station uplink channel Gaussian white noise channel adopts 8PSK modulation, the code rate is 0.891, and the receiving signal-to-noise ratio is 10dB. Assuming that the up-sampling frequency offset is 5000 Hz, the sampling frequency offset is estimated by only relying on the segmental correlation of the reference signal in step 2 without the pre-compensation in step 1. The simulation results are as Figure 5 As shown, the estimated root mean square error obtained by simulation is 32.4 Hz, which shows that this method has high accuracy in estimating the upstream residual sampling frequency offset. As shown in the simulation results, the sampling frequency offset will bring about a 2.6dB performance loss to the system in this simulation scenario, and after estimation and compensation by the algorithm of the present invention, the link performance is compared with the ideal link without sampling frequency offset The performa...

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Abstract

The invention discloses a low-orbit satellite multi-carrier communication system uplink sampling frequency offset estimation and compensation method. The uplink refers to a transmission link transmitted by a user terminal, forwarded by a satellite, and received by a gateway station. The specific method is as follows: the user terminal calculates the uplink pre-compensation sampling frequency offset value according to the estimated value of the downlink sampling frequency offset, and pre-compensates the uplink transmission signal by adjusting the crystal oscillator or using a resampling digital filter; The segment correlation algorithm estimates the uplink residual sampling frequency offset, and compensates the uplink received signal in the frequency domain. By using the method of the invention, the system can realize large-scale, high-precision, and low-complexity estimation and compensation of uplink sampling frequency deviation, so as to meet the demodulation requirements of multi-carrier communication under the large Doppler sampling frequency deviation of low-orbit satellites.

Description

technical field [0001] The invention belongs to the field of wireless communication, and in particular relates to a method for estimating and compensating for uplink sampling frequency offset in low-orbit satellite multi-carrier communication. [0002] technical background [0003] With the development of communication requirements, in order to meet the high-speed data transmission in remote areas without base station coverage, in the future mobile communication, the realization of communication coverage in remote areas through low-orbit satellites has become an important topic. A typical low-orbit satellite communication system such as figure 1 As shown, the system components include: (1) gateway station, (2) satellite, (3) user terminal. (2) The satellite is only responsible for transparent forwarding, that is, it only performs frequency-shift forwarding processing on the received signal, and does not modulate and demodulate the signal. The link between the gateway and th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L27/38H04L27/26H04L27/00
CPCH04L27/3872H04L27/2657H04L27/0014H04L2027/0026
Inventor 张毅刘田马松袁田夏彬徐元浩
Owner 上海众睿通信科技有限公司
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