A demodulation method for UHF RFID signal under low signal-to-noise ratio
A technology with low signal-to-noise ratio and demodulation method, which is applied in the near-field transmission system, instrument, electromagnetic radiation induction and other directions in the radio frequency identification system, and can solve the problems of difficult demodulation, complex electromagnetic environment, and long receiving distance.
Active Publication Date: 2020-10-23
NO 30 INST OF CHINA ELECTRONIC TECH GRP CORP
View PDF7 Cites 0 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
However, due to the long receiving distance and complex electromagnetic environment, and because the energy signal of the reader and the tag signal have the same transmission frequency, and are affected by factors such as multipath effects and environmental interference, it is difficult to correctly demodulate based on traditional methods
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0021] The invention proposes a demodulation method of ultra-high frequency RFID signals under low signal-to-noise ratio. The core idea is to use the adaptive noise reduction algorithm and the optimized blind synchronous demodulation implementation structure, so it has good performance. In the preprocessing process, it is first necessary to perform quadrature down-conversion on the received signal. In order to reduce noise interference, band-pass filter processing is added, which can reduce the signal-to-noise ratio loss caused by nonlinear processing in subsequent operations to a certain extent. but from figure 2 It can be seen from the figure that the modulation waveform of the tag signal at this time is "suspended" on the undulating envelope of the DC component and the residual carrier signal. In order to restore the baseband modulation waveform of the signal, it is necessary to remove these interferences and further reduce the influence of noise, otherwise the RFID infor...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
Login to View More Abstract
The invention discloses a demodulation method for ultra-high frequency RFID signals under low signal-to-noise ratio, which includes the following steps: Step 1: Use a preprocessing method based on adaptive fitting to fit the changing envelope curve of the RFID signal, Then perform descrambling to obtain the baseband signal; Step 2: First perform correlation matching on the RFID baseband signal waveform, then use the combination of frame header filter output and feedback information for alignment processing, and then perform "1" and "0" encoded waveforms respectively. Matching processing, and finally judging the matching output at the best sampling point position to obtain the final demodulation result. The invention not only has strong anti-noise and anti-interference performance, but also can be better adapted to harsh electromagnetic environments, requires fewer signal sample points, and has less computational complexity. It is suitable for RFID signal monitoring systems and cognitive radio receiving systems. , traffic signal control systems, etc. all have high engineering practical value. At the same time, the demodulation method of the present invention has superior performance and strong applicability.
Description
technical field [0001] The invention relates to a demodulation method for ultra-high frequency RFID signals under low signal-to-noise ratio. Background technique [0002] Radio Frequency Identification (RFID) is an automatic identification technology, which uses radio frequency signals and spatial coupling transmission characteristics to realize automatic identification of objects. With the development of wireless communication and Internet of Things research, RFID technology has risen rapidly in various fields, forming a huge industrial chain. The typical working frequency of UHF RFID signal mainly includes 433MHz, 860MHz to 960MHz, etc. Its data transmission rate is high, the anti-collision mechanism is relatively complete, and it can read a large number of tags at the same time. It has been used in intelligent transportation, intelligent manufacturing, and logistics. , identification and many other aspects, more and more attention has been paid. Based on the RFID system...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Patents(China)
IPC IPC(8): G06K7/10G06K7/00H04B5/00
CPCG06K7/0008G06K7/10297H04B5/77
Inventor 熊刚饶志宏张晓康荣保刘丹
Owner NO 30 INST OF CHINA ELECTRONIC TECH GRP CORP