Gen2-UHF-RFID-Reader: A Python repository from marceluphd

This is a Gen2 UHF RFID Reader. It is able to identify commercial GEN2 RFID Tags with FM0 line coding and 40kHz data rate (BLF) and extract their EPC 
message.It requires USRPN200 and was tested with a single front-end card (RFX900).
Developed by Nikos Kargas in the context of his MSc thesis,
School of Electronic & Computer Engineering, Technical Univ. of Crete.  

The project was initially based on the RFID Gen 2 Reader available at https://www.cgran.org/wiki/Gen2 (Contributor: Michael Buettner). To make it compatible
with the latest version of Gnuradio and UHD as well as USRPN200 I decided to write a Gen2 Reader from scratch borrowing elements from the Reader developed by
Buettner i.e. Data flow: Gate -> Decoder -> Reader as well as the conception regarding the detection of the reader commands. CRC calculation and checking
functions were also adapted from https://www.cgran.org/browser/projects/gen2_rfid/

Implemented Gnuradio Blocks:
  Gate: Responsible for reader command detection.
  Tag decoder: Responsible for frame synchronization, channel estimation, symbol period estimation and detection.
  Gen2 Logic : Create reader commands.

RFID Reader configuration:
  set USRPN200 address in apps/reader.py (default: 192.168.10.2)
  set frequency in apps/reader.py (default: 910MHz)
  set tx amplitude in apps/reader.py (default: 0.1)
  set rx gain in apps/reader.py (default: 20)
  set maximum number of queries in include/global_vars.h (default:1000)
  set number of inventory round slots in include/global_vars.h (default: 0)

Installation instructions:

  install UHD driver + GNU Radio using 
  wget http://www.sbrac.org/files/build-gnuradio && chmod a+x ./build-gnuradio && ./build-gnuradio

  cd Gen2-UHF-RFID-Reader/gr-rfid/
  mkdir build
  cd build/
  cmake ../ (logging should be enabled)
  sudo make install

How to run:

  Real time execution :
    cd Gen2-UHF-RFID-Reader/gr-rfid/apps/
    sudo GR_SCHEDULER=STS nice -n -20 python ./reader.py 
    After termination, part of EPC message (hex value of EPC[104:111]) of identified Tags is printed 

  To run with offline data : 
    change DEBUG variable in apps/reader.py to TRUE (A test file already exists named file_source_test)
    The reader works with offline traces without using a USRP.

    output after running with test file:

     --------------------------
    | Number of queries/queryreps sent : 71
    | Current Inventory round : 72
     --------------------------
    | Correctly decoded EPC : 70
    | Number of unique tags : 1
    | Tag ID : 27  Num of reads : 70

  Output
    /misc/data/source  
    /misc/data/matched_filter  
    /misc/data/gate 
    /misc/data/decoder  
    /misc/data/reader

    /misc/code/plot_signal.m   # Plot using Matlab/Octave

How logging works:
    Configuration file : /home/username/.gnuradio/config.conf
    Edit the above file and add the following lines

    [LOG]
    debug_file = /PathToLogFile/Filename
    debug_level = info 

    --logging may cause latency issues if it is enabled during real time execution. However it can be used with offline traces.

Hardware:
  1x USRPN200
  1x RFX900 daughterboard
  2x circular polarized antennas

Tested on:
  Ubuntu 14.04 64-bit
  GNU Radio 3.7.4  

Contact:
  Nikos Kargas (e-mail1: nkargas@isc.tuc.gr email2: cpznick@gmail.com)
  MSc Student, Technical University of Crete

This research has been co-financed by the European Union (European Social Fund-ESF) and Greek national funds through the Operational Program Education and
Lifelong Learning of the National Strategic Reference Framework (NSRF) - Research Funding Program: THALES-Investing in knowledge society through the European Social Fund.
marceluphd/Gen2-UHF-RFID-Reader
