Physical layer transmission method and device suitable for simple satellite Internet of Things terminal

Abstract

A physical layer transmission method and device suitable for a simple satellite Internet of Things terminal are applied to a stationary satellite Internet of Things terminal, and the method comprisesthe following steps: S100, performing correction for a predetermined number of times when the satellite Internet of Things terminal accesses a network to enable the satellite Internet of Things terminal to reach a synchronous state, wherein the preset number of times does not exceed 10, and the correction comprises frequency deviation synchronization and / or time deviation synchronization; S200, when the satellite Internet of Things terminal reaches the synchronization state, carrying out no correction or carrying out correction according to the frequency of no more than 1 day / time. Aiming at the characteristics that the total number of the Internet of Things terminal devices is large and the sending time of each device is short and the interval is long, coarse synchronization is used for transmission, signaling bandwidth occupation caused by high-frequency synchronization such as TDMA complete synchronization is not needed, the guard interval is smaller than that of complete non-synchronization, and the networking capability of the whole system is improved.

Description

technical field [0001] The invention relates to satellite Internet of Things communication technology, in particular to a physical layer transmission method suitable for simple satellite Internet of Things terminals. Background technique [0002] MF-TDMA satellite communication system is mainly used in high-orbit synchronous communication satellites based on the principle of transparent forwarding. The forward link of the communication system adopts large-bandwidth TDM continuous carrier, and the return link adopts MF-TDMA system. The return link in the protocol requires all remote stations in the system network to maintain frequency and time synchronization with the central station, and synchronize at the second level. The time difference between the master station and the terminal station is small, and the accuracy is accurate. [0003] Such as figure 1 As shown, the TDMA network-wide synchronization method when the central station and the remote station that includes m...

AI Technical Summary

Problems solved by technology

[0004] If you want to apply the second-level synchronization in the MF-TDMA system to the Internet of Things, the Internet of Things requires a large number of terminals, and second-level synchronization across the entire network will cause the air interface link to send signaling messages all the time, wasting bandwidth and limiting the system capacity

[0005] If the remote station does not synchronize with the main station and adopts the TDMA system, because the time between the main station and the end station is not calibrated, the link delay is estimated according to GPS, and each effective time slot transmission requires a large guard time interval

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