This work presents a digital reception system for a radio-frequency identi-
cation (RFID) reader, in the high frequency (HF) domain. The protocols, for
which the reception system was designed, fall into a subcategory of RFID called
near-eld communication (NFC), where the carrier frequency is 13.56 MHz.
The goal of this work was to design a part of the reception system of a HF
RFID reader, called the correlation system. For this purpose, the concept, ope-
ration, and composition of the correlation system, implemented in the digital
domain, are described. The advantages of a digital implementation over an ana-
log implementation are put forth. The motivation for developement was the
improvement of sensitivity to signals and robustness to inteferance of a HF RFID
reader reception system.
An overview of the state of the art of RFID reader reception systems is pre-
sented, with a focus on NFC readers. Upon investigation, it is found that there is
a distinct lack of articles on the topic of NFC reader reception systems, compared
to other areas of RFID.
A description of the composition of the reception system is given, beginning
with the antenna system of the reader and smart card. The description continues
with the analog part and digital part, where the essential design guidelines are
presented. The description is concluded by a detailed description of the concept,
components, and dierent modes of operation of the digital correlation system.
The reception system of a reader comprises of an analog part, where direct
conversion, amplication, and ltering are performed and the digital part, where
digital ltering, correlation, and symbol recognition are performed. An analog to
digital converter serves as a bridge between the analog and digital domains. The
output of the digital lters represents a discrete multi-bit signal at the subcarrier
frequency. Using the properties of the signal, such as bit coding and data packet
structure, simplied correlation is implemented. The operation of correlation is
broken down into its three fundamental components (multiplication, phase or
time shift, and averaging), which form the digital correlation system.
The operation and performances of the digital correlation system are deter-
mined by bit or packet error rate measurements, rst on a FPGA developement
board and secondly on the nal integrated circuit. The results are graphically
presented and commented upon. A comparison with theoretical bit or packet
error rates of NFC protocol coding schemes shows dierences in signal to noise
ratios from 2.4 dB to 6.4 dB, depending on protocol and data rate. These die-
rences are attributed to the dierence between theoretical value calculation and
real data packet measurements, where the start of the data packet must also be
successfully detected.
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