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An all-digital synchronization method for broadband frequency-hopping direct-spread signals without data assistance

A data-free, direct-spread signal technology, applied in digital transmission systems, electrical components, transmission systems, etc., can solve the problem of decreased confidentiality and anti-interference performance of jump-spread systems, increased receiver manufacturing costs, and increased frame design overhead And other issues

Active Publication Date: 2020-09-18
XIAN INSTITUE OF SPACE RADIO TECH
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Problems solved by technology

Obviously, (1) puts forward higher requirements on the communication system design and the control precision of the front-end channel, which greatly increases the manufacturing cost of the receiver; (2) and (3) due to the introduction of the training sequence, the frame design overhead will inevitably increase, And cause the confidentiality performance and anti-interference performance of the jump-spread system to decline

Method used

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  • An all-digital synchronization method for broadband frequency-hopping direct-spread signals without data assistance
  • An all-digital synchronization method for broadband frequency-hopping direct-spread signals without data assistance
  • An all-digital synchronization method for broadband frequency-hopping direct-spread signals without data assistance

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Experimental program
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Embodiment

[0088] Suppose the received signal has figure 1 The signal format shown, the received signal can be described by the following formula:

[0089]

[0090] Among them, D represents the data symbol, and the value is {1,-1}; the symbol period seconds; direct spread pseudo-code period N = 1000; chip width seconds; Fh means frequency hopping carrier frequency point, press {Fh 0 fh 1 ...Fh 4}Frequency hopping carrier frequencies occur sequentially; Th represents the dwell time of each frequency hopping frequency point; Fd is the carrier frequency offset of the received signal, |Fd|≤Fd max =40kHz, the transmission bandwidth Bw of the hop-spread signal S(t)=1GHz. Th=T s = 1000Tc.

[0091] combine image 3 , according to step 1, using a non-coherent search algorithm to serially search the phase of the direct spread code, and obtain a rough estimate of the phase of the direct spread code and a rough estimate of the carrier frequency offset.

[0092] Step 1. Divide the car...

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Abstract

The invention relates to a non-data-aided broadband frequency hopping / direct spread signal full digital synchronization method. According to the method, direct spread codes, frequency hopping codes and data symbols of frequency hopping / direct spread signals are required to be coherent. The method comprises the specific operation of serially searching direct spread code phases through adoption of an incoherent search algorithm, thereby obtaining coarse estimation values of the direct spread code phases and the coarse estimation values of carrier frequency offset; traversing hopping time of local de-hopping carriers through adoption of a relatively small time interval within an error range of the coarse estimated values of the direct spread code phases, and obtaining fine estimation of the hooping time and the fine estimation of the carrier frequency offset in a coherent accumulation+peak judgment mode of a plurality of de-hopping symbols; and adjusting the hopping time in real time through utilization of symbol synchronization deviation estimated by a tracking module, thereby assisting a receiver to carry out coherent demodulation. According to the method, receiving of large broadband frequency hopping / direct spread signals is realized through adoption of a pure digital method, the method can work under a low signal to noise ratio and high frequency dynamic state, the method isinsensitive to signal structures, and the method can be widely applied to different frequency hopping / direct spread signal receivers.

Description

technical field [0001] The invention relates to the technical field of frequency hopping / direct spread (FH / DS) hybrid anti-jamming communication, in particular to a signal format with coherent direct spread code, frequency hopping code and data symbol. Background technique [0002] The frequency hopping / direct spread (FH / DS) hybrid spread spectrum communication system combines the direct sequence spread spectrum technology and the frequency hopping spread spectrum technology, which not only has the confidentiality of the low power spectral density of the direct spread signal, but also has the advantages of frequency hopping. The anti-jamming gain brought by the ultra-large bandwidth of the signal is recognized as the most vigorous anti-jamming system at home and abroad. Therefore, the use of direct spread frequency hopping hybrid communication system can effectively guarantee the security and reliability of communication in complex electromagnetic environments. [0003] How...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B1/713H04B1/7087H04B1/7073H04L27/00
CPCH04B1/7073H04B1/7087H04B1/713H04L27/0014H04L2027/0026
Inventor 孟向阳翟继强王大庆李雄飞王欣王建诚
Owner XIAN INSTITUE OF SPACE RADIO TECH
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