Zynq-based WISER platform - Spectrum Sensing

Description

This tutorial demos capturing spectrum data using the Zynq-based WISER platform on ORBIT.

Hardware / Software Resources utilized

1. An SB6 node with WISER platform connected to it.
2. wiser_sb6_zedboard.ndz: disk image.

Set up

• Follow the start-up instructions to set up the load the node image and FPGA images.

• After the set-up is complete, ssh into node1-1 and build the wiserd application

  root@node1-1:~# cd wiserd
  root@node1-1:~/wiserd# make clean
  root@node1-1:~/wiserd# make
  g++   -Wall -g -O -std=gnu++0x  -c -o channel_status.o channel_status.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o consumer_moving_average.o consumer_moving_average.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o fft_movavg_dc.o fft_movavg_dc.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o fft_movavg_oml.o fft_movavg_oml.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o fft_movavg_udp.o fft_movavg_udp.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o fft_pow_udp.o fft_pow_udp.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o fft_sigpower_oml.o fft_sigpower_oml.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o main.o main.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o radio.o radio.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o recv_consumer_factory.o recv_consumer_factory.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o recv.o recv.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o signal_from_file.o signal_from_file.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o time_samples_to_file.o time_samples_to_file.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o tran_consumer_factory.o tran_consumer_factory.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o tran.o tran.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o usrp.o usrp.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o waveform.o waveform.cpp
  g++   -Wall -g -O -std=gnu++0x  -c -o zynq.o zynq.cpp
  g++ -L/usr/local/lib channel_status.o consumer_moving_average.o fft_movavg_dc.o fft_movavg_oml.o fft_movavg_udp.o fft_pow_udp.o fft_sigpower_oml.o main.o radio.o recv_consumer_factory.o recv.o signal_from_file.o time_samples_to_file.o tran_consumer_factory.o tran.o usrp.o waveform.o zynq.o -o wiserd -lboost_system -lboost_random -lboost_thread -lboost_program_options -lboost_iostreams -lpthread -llog4cxx -luhd -loml2 -locomm -lfftw3f -lreadline
  

Start spectrum sensing

• Run the wiserd application with the following arguments.

  root@node1-1:~/wiserd# ./wiserd --zynq_rx_freq 820e6 --zynq_rx_gain 10 --zynq_fft_bins 256 --zynq_fft_scaling 170 --zynq_avg_window 256
  linux; GNU C++ version 4.8.2; Boost_105400; UHD_003.008.002-86-g566dbc2b
  
  Zynq constructed
  zynq_fft_bins 8
  zynq_fft_scaling 170
  zynq_rx_freq 820000000
  zynq_rx_gain 10
  Ready!
  Zynq thread started
  >
  

• The Zynq parameters passed to the FPGA to configures the RF hardware and FFT engine
  a) '—zynq_rx_freq 820e6' ——> sets Rx center frequency. Range of values: [400M 4000M]
  b) '—zynq_rx_gain 10' ———→ sets Rx amplifier gain. Range of values: [5.0 20.0]
  c) '—zynq_fft_bins 256' ——→ sets FFT size. Range of values must be power of 2: [8 256]
  d) '—zynq_fft_scaling 170' —> sets FFT stage scaling.
  e) '—zynq_avg_window 256' —→ sets time averaging across bins. Range of values: [1 256]
  

Note: the sampling rate not configurable and fixed at 30Msps.

• From wiserd enable FFT engine and start streaming frequency bins from the FPGA to host

  > --fft_engine 1
  

• The FFT bin data is collected in binary file name zynq_rx_fft.bin

• From wiserd disable FFT engine and stop streaming data to host

  > --fft_engine 0
  

• To view a water fall image collected rx spectrum data, run the fPlot script in octave. A sample image is shown below with a tone at 10MHz generated from a USRP.