A Random Access Method Oriented to LEO Satellite Communication System

Abstract

The invention provides a random access method for a low-orbit satellite communication system, and belongs to the technical field of satellite communication. According to the random access method provided by the invention, the working state information of an on-board demodulator is mainly used for assisting a user terminal to perform link state sensing, and meanwhile a probability parameter P is dynamically broadcasted according to the satellite position to improve the system throughput of an access link. When the on-board demodulator performs uplink signal demodulation, a channel busy state isindicated according to the actual state of the demodulator and is broadcasted to a ground terminal through a downlink together with a terminal identification data block. The channel busy state sharesa 2-bit identifier. In addition, by using the global terminal location management feature of a constellation system service operation center, terminal number parameter data within the dynamic satellite beam coverage are formed and are broadcasted to the user terminal in real time through the satellite for dynamically changing the data sending probability parameter P of the terminal, and the throughput of random access of the user link is optimized from the system level.

Description

technical field [0001] The invention relates to a random access method for a low-orbit satellite communication system, belonging to the technical field of satellite communication. Background technique [0002] The multiple access method is the main composition method of the entire low-orbit communication satellite communication system, which is related to the access efficiency of the entire communication system. The multiple access methods commonly used in low-orbit satellite communication systems in the world are divided into service access multiple access methods and signaling access multiple access methods. The business access multiple access methods usually use TDMA, CDMA, and FDMA. Access generally adopts the ALOHA mode of random competition. [0003] Typical links of low-orbit satellites for data collection and short message exchange are as follows: figure 1 As shown, on-board processing methods are generally used, such as Orbcomm, Argos abroad, and the Hongyan const...

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Problems solved by technology

For example, the document "Throughput Analysis of CSMA With Imperfect Collision Detection in Full Duplex-Enabled WLAN" (IEEE Wireless Communications Letters, 2017) mainly focuses on the research of CSMA algorithm with partial collision detection in full-duplex mode, analysis and simulation in different wireless environments, Under different user distributions and different collision modes, the algorithm improves the throughput rate, and compares the throughput of the traditional random access protocol, which proves the improvement of the throughput rate of the CSMA algorithm for partial collision detection. The paper focuses on Discuss the access algorithm at different frequencies in the wireless local area network WLAN, and its application scenario is not suitable for on-board processing of low-orbit satellites

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