Title
Spread-Spectrum Based Ranging of Passive UHF EPC RFID Tags
Abstract
This letter introduces a ranging method which can be applied to off-the-shelf backscatter RFID tags, like standardized EPC Gen 2 tags. For this purpose a low power direct sequence spread spectrum (DSSS) sequence is superimposed onto the interrogator's signal during tag to reader communication. The chip rate and sequence length is chosen to fit an entire DSSS sequence into each backscattered bit. During the tag to reader communication, the bits sent by the tag are decoded and a time domain recording with the length of one DSSS period is made for each bit. By cyclic alignment of each recording and subtracting the averaged recording of a 0-bit from the one of a 1-bit, static echos and antenna coupling effects are perfectly canceled. In addition, noise variance is reduced, improving the SNR. Finally, by applying a cyclic correlation with the transmitted DSSS sequence and locating the correlation maximum, the distance to the RFID tag can be determined.
Year
DOI
Venue
2015
10.1109/LCOMM.2015.2469664
IEEE Communications Letters
Keywords
Field
DocType
Spread spectrum communication,Distance measurement,Antennas,Radiofrequency identification,Standards,Modulation,Backscatter
Time domain,Telecommunications,Computer science,Backscatter,Real-time computing,Modulation,Chip,Ranging,Direct-sequence spread spectrum,Computer hardware,Ultra high frequency,Spread spectrum
Journal
Volume
Issue
ISSN
19
10
1089-7798
Citations 
PageRank 
References 
10
1.41
1
Authors
3
Name
Order
Citations
PageRank
H. Arthaber1165.91
T. Faseth2114.13
Florian Galler3102.43