gr-ltetrigger

Note: this repository is currently unmaintained and unsupported

gr-ltetrigger is a set of utilities for sensing LTE. It is built using GNU Radio and srsLTE.

Screenshots

.. image:: docs/gr_ltetrigger_rtlsdr_demo.png :alt: GRC example showing LTE downlink parameters using RTL-SDR :align: center

.. image:: docs/gr_ltetrigger_snr_demo.png :alt: GRC example showing cell detection algorithm performance by SNR :align: center

Building

. Install SWIG, GNU Radio, GNU Radio Companion, fftw and gr-osmosdr (example

assumes Ubuntu 16.04, adjust as needed)

.. code:: bash

         $ sudo apt install gnuradio-dev swig fftw-dev gr-osmosdr libuhd-dev

. Install the dependencies of srsLTE. See https://github.com/srslte/srslte for

a command for Ubuntu.

. Build and install srsLTE. There is a naming collision between srsLTE and a

requirement of GNU Radio (log4cpp), which we must fix before building:

.. code:: bash

         $ git clone https://github.com/srslte/srslte
         $ cd srslte
         $ git checkout tags/release_18_06_1  # newer releases may work
         $ grep -R -l " DEBUG(" . |xargs sed -i 's/ DEBUG(/ DEBUG_(/g'
         $ grep -R -l " ERROR(" . |xargs sed -i 's/ ERROR(/ ERROR_(/g'
         $ find -name ue_cell_search.c |xargs sed -i 's/DEBUG/DEBUG_/g'
         $ mkdir build; cd build
         $ cmake ../
         $ make && make test
         $ sudo make install

. Build and install gr-ltetrigger:

.. code:: bash

         $ git clone https://github.com/NTIA/gr-ltetrigger
         $ cd gr-ltetrigger
         $ mkdir build; cd build
         $ cmake ../
         $ make && make test
         $ sudo make install
         $ sudo ldconfig

Quick Start

.. code:: bash

      $ cd gr-ltetrigger/examples
      $ ./cell_search_file.py --help
      linux; GNU C++ version 5.3.1 20160413; Boost_105800; UHD_003.010.git-202-g9e0861e1

      usage: cell_search_file.py [-h] -s Hz [-f Hz] [--repeat] [-c N]
      [--throttle Hz] [--time-out sec]
      [--threshold THRESHOLD]
      filename

      positional arguments:
      filename

      optional arguments:
      -h, --help            show this help message and exit
      -s Hz, --sample-rate Hz
      input data's sample rate [Required]
      -f Hz, --frequency Hz
      input data's center frequency
      --repeat              loop file until cell found or cut-off reached
      [default=False]
      -c N, --cut-off N     stop looping after N samples [default=-1]
      --throttle Hz         throttle file source to lower CPU load [default=None]
      --time-out sec        max time in seconds to perform search [default=-1]
      --threshold THRESHOLD
      set peak to side-lobe ratio threshold [default=4]
      $ ./cell_search_file.py --sample-rate 15.36M ../test_frames/lte_frame_50prb_cellid_125 --repeat --time-out 1
      linux; GNU C++ version 5.3.1 20160413; Boost_105800; UHD_003.010.git-202-g9e0861e1

      Using Volk machine: avx2_64_mmx
      Starting cell search... done.
      {'cell_id': 125L,
      'cp_len': 'Normal  ',
      'nof_phich_resources': '1',
      'nof_prb': 50L,
      'nof_tx_ports': 1L,
      'phich_len': 'Normal',
      'sfn_offset': 0L,
      'tracking_start_time': 1464123775L}

Support

Douglas Anderson | NTIA/Institute for Telecommunication Sciences | danderson@ntia.doc.gov

Legal

See LICENSE_.

.. _LICENSE: LICENSE.txt