Analysis of Demodulation Algorithm For Data Transmission In Low Orbit

In order to solve the problems of signal attenuation and low transmission efficiency in low-orbit satellite data transmission, this paper analyzes and implements an effective modulation and demodulation algorithm. First, in view of the frequent interruption of links in low-orbit environments, a scheme based on QPSK (Quadrature Phase Shift Keying) modulation is designed, combined with Forward Error Correction (FEC) to improve anti-interference capability. Then, the ACM (Adaptive Coding and Modulation) adaptive equalization technology is introduced to deal with the nonlinear effect of channel attenuation, and the transmission efficiency is maximized by adjusting the spectrum resource allocation. Finally, this paper conducts experimental verification on an actual low-orbit satellite communication link. The experimental results show that under the condition of 20dB signal-to-noise ratio (SNR), the bit error rate (BER) of the scheme using QPSK modulation combined with FEC coding is reduced. After combining ACM technology, under the SNR condition of 20dB, the system transmission rate is increased to 0.85bps/H, and under high spectrum resource configuration, ACM technology shows more significant performance improvement. From the above data conclusions, the modulation and demodulation algorithm proposed in this paper can effectively deal with channel fading and interference in low-orbit satellite communication systems, improve data transmission efficiency, and has strong anti-interference ability.