Joint Channel Detection, Phase Recovery and Decoding Method Based on Markov Chain

Abstract

The invention discloses a joint channel detection, phase retrieval and decoding method based on the Markov chain in the technical field of helicopter satellite communications. The method comprises the following steps: firstly establishing a joint channel detection, phase retrieval and decoding system, uniformly inserting reference symbols at a sending end, and receiving a signal at a receiving end; processing the received signal through a phase-locked loop circuit, initializing a sending symbol probability distribution, a phase state probability distribution and a prior shielding proportion; inputting the signal processed by the phase-locked loop circuit to a channel detector and a phase retriever; performing channel detection by establishing a Markov model; and determining a shielding interval. The system in the invention is strong in self-adaptive ability to the shielding proportion dynamic change, the method result shows that a bit error rate performance curve completely approaches to a demodulation decoding algorithm under the known channel state, and the reliability of the helicopter satellite communication is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of helicopter satellite communication, in particular to a joint channel detection, phase recovery and decoding method based on Markov chain. Background technique [0002] At present, helicopters often use short-wave and ultra-short wave for communication. However, short-wave communication is easily affected by the environment, and the communication distance of ultra-short wave communication is limited. Helicopter satellite communication makes full use of the characteristics of satellite communication, has the characteristics of strong adaptability, long communication distance, and large coverage, and plays a key role in various fields such as military and civil affairs. In the helicopter satellite communication system, the airborne communication equipment is generally installed under the rotor in order not to affect the balance of the body. This installation method causes the helicopter satellite communicati...

AI Technical Summary

Problems solved by technology

In the helicopter satellite communication system, the airborne communication equipment is generally installed under the rotor in order not to affect the balance of the body. This installation method causes the helicopter satellite communication signal to be affected by the shielding of the rotor, which poses a new challenge to carrier synchronization.

[0003] In view of the problem that the rotor blocks the communication signal, the traditional carrier synchronization method will not work stably due to the blockage of the rotor when realizing the carrier phase recovery, which brings difficulties to the signal recovery

At the same time, in the actual flight of the helicopter, the ratio of rotor occlusion changes dynamically, resulting in a decrease in decoding performance.

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