Code-assisted carrier phase synchronization system and method for deep space communication

Abstract

The invention provides a deep-space communication oriented code-aided carrier phase synchronization system and a deep-space communication oriented code-aided carrier phase synchronization method. The deep-space communication oriented code-aided carrier phase synchronization system comprises a receiving-end unit. The receiving-end unit comprises an LDPC (low-density parity check) decoder, a multiplier, a Costas loop module, a rotational metric function generator and a phase compensator. The deep-space communication oriented code-aided carrier phase synchronization system and the deep-space communication oriented code-aided carrier phase synchronization method have the advantages that a gain per square loss of the system conforms to a theoretical gain, a phase acquisition range of the system is wide as compared with an existing IRCS (information-reduced carrier synchronization) scheme and an EM (expectation-maximization) algorithm, phase deviation within a + / -180-degree range can be correctly estimated, and the complexity is low as compared with a phase deviation search algorithm.

Description

technical field [0001] The invention relates to the technical field of deep space communication, in particular to a code-assisted carrier phase synchronization system and method for deep space communication. Background technique [0002] In the process of deep space exploration, deep space communication plays a key role. Only by ensuring the normal operation of the deep space communication system can the deep space exploration mission be successful. However, deep space communication is facing challenges that ground communications and satellite communications cannot achieve. It has special difficulties, because the deep space channel has the following characteristics: long distance, long delay, channel fading characteristics, high operating frequency, available frequency bandwidth, easy link interruption, asymmetric uplink and downlink, etc. [0003] The propagation distance of deep space communication is extremely long, the signal energy attenuates with the square of the dee...

AI Technical Summary

Problems solved by technology

The demodulation and decoding module can still perform good bit error performance when the SNR is as low as -1.4dB, but the working threshold of the phase-locked loop cannot meet this condition, which is the bottleneck of the independent design of decoding and detection

[0009] If the carrier synchronization scheme with low signal-to-noise ratio and large phase deviation used in the past is applied to deep space communication, there will be the following problems: First, the working mode adopted by the existing estimation decoding system is not suitable for deep space Communication channel characteristics

Second, the existing joint estimation decoding system has a large cross product of signal and noise in the estimation loop under low SNR, resulting in large loop noise and large mean square phase error

Third, the existing algorithms do not consider the characteristics of the joint estimation decoding scheme, and propose a phase ambiguity solution

In this way, the capture range of the recursive estimation loop is small, and in the case of large phase deviation, it is easy to encounter hysteresis

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