According to a news release from the website of the Institute of Remote Sensing and Space Information, Chinese Academy of Sciences on November 14, the Chinese Academy of Sciences Institute of Remote Sensing and Space Information (hereinafter referred to as the "Institute") jointly with Beijing Rongwei Technology Co., Ltd. (Rongwei Company) recently organized a high-rate microwave satellite-to-ground communication experiment at the Lijiang Station of the Institute, focusing on verifying high-order modulation and demodulation technology.
This experiment successfully increased the data transmission rate in the X band to 6.0 gigabits per second (Gbps) and the Ka band to 20 Gbps, setting a new record for data transmission rate, marking an important technical breakthrough in this field in China.
Insufficient satellite-to-ground transmission bandwidth has always been a core bottleneck restricting the utilization efficiency of satellite payloads in China. The use of high-order modulation and demodulation technology can significantly improve the frequency band utilization efficiency, which is the most economical and effective technical means to increase the satellite-to-ground transmission rate. However, the higher the modulation order, the greater the impact of non-linear transmission channels, phase noise, and other factors on the signal, leading to high data bit error rates, which are difficult to meet the quality requirements for satellite data reception, thus becoming a technical challenge that needs to be urgently addressed in the industry.
To solve this problem, the Institute and Rongwei Company have continuously conducted research on various non-ideal factors affecting high-order systems, breaking through key technologies such as deep neural network nonlinear distortion correction, high-performance channelization adaptive linear distortion correction, and grid backtracking phase noise compensation. They have successfully developed core algorithms such as intelligent polarization interference cancellation and deep neural network adjacent channel interference elimination, and established an advanced ground receiving system technical index system, laying a solid foundation for the success of this experiment.
This experiment, based on the latest technological research results of both parties, systematically verified the effectiveness of high-order modulation and demodulation technology in improving the bandwidth utilization of X-band and Ka-band data transmission through a series of wired and wireless satellite-to-ground connection tests. The experimental results showed that under the 1024 Quadrature Amplitude Modulation (QAM) high-order system in the X band, dual-channel 6.0 Gbps high-rate communication can be achieved; under the 512QAM high-order system in the Ka band, using a dual-carrier and polarization multiplexing scheme, four-channel 20.16 Gbps high-rate communication can be achieved, and using a single-carrier and polarization multiplexing scheme, two-channel 12.8 Gbps high-rate communication can be achieved. During the experiment, the constellation diagram showed no significant distortion, and the bit error rate could be zero with some margin. This is another record for the highest data transmission rate in the X band and Ka band for satellite-to-ground communication, following the successful verification of high-throughput data communication technology in the X band at 2.1 Gbps@128QAM (2.1 gigabits per second communication rate under the 128 Quadrature Amplitude Modulation mode) earlier this year.
Huang Peng, director of the China Remote Sensing Satellite Ground Station affiliated with the Institute and researcher, said: "This experiment fully verifies the application value of high-order modulation and demodulation technology, with relevant indicators reaching international leading levels. Currently, this technology is about to be applied to actual satellite data receiving tasks, which is of great significance for effectively solving the problem of insufficient satellite-to-ground transmission bandwidth and enhancing the application efficiency of China's satellites in the future."
Constellation diagram and bit error rate situation for the Ka band four-channel experiment
Constellation diagram and bit error rate situation for the X band two-channel experiment
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