Gnuradio - LoRa SDR

Fully-functional GNU Radio blocks to implement the physical layer (PHY)of LoRa
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Summary

This is the fully-functional GNU Radio software-defined radio (SDR) implementation of a LoRa transceiver with all the necessary receiver components to operate correctly even at very low SNRs. This work has been originally conducted at the Telecommunication Circuits Laboratory, EPFL and later the code has been extended at the Technical University of Eindhoven.

Extended work

The extended work of this project is to provide a higher level use case for the original code, this is done by :

• Abstracting the individual rx and tx chains in easy to use blocks

This is done to extend to higher level systems such as:

• Implementing a simulated multi-stream gateway, this is currently implemented in an experimental version. As desribed in paper.
• Implementing an open-source CRAN (Centralised Radio Acces Network) implementation using ZMQ worker <-> broker <-> worker struicture, this is currently WIP for more information on this go to loudify

About this code

In the GNU Radio implementation of the LoRa Tx and Rx chains the user can choose all the parameters of the transmission, such as the spreading factor, the coding rate, the bandwidth, the presence of a header and a CRC, the message to be transmitted, etc.

• In the Tx chain, the implementation contains all the main blocks of the LoRa transceiver: the header- and the CRC-insertion blocks, the whitening block, the Hamming encoder block, the interleaver block, the Gray mapping block, and the modulation block.
• On the receiver side there is the packet synchronization block, which performs all the necessary tasks needed for the synchronization, such as the necessary STO and CFO estimation and correction. The demodulation block follows, along with the Gray demapping block, the deinterleaving block, the Hamming decoder block and the dewhitening block, as well as a CRC block.

With the following parameters available:

• Spreading factors: 7-12 (without reduce rate mode)
• Coding rates: 0-4
• Implicit and explicit header mode
• Payload length: 1-255 bytes
• Sync word selection (network ID)
• Verification of payload CRC
• Verification of explicit header checksum

Credit

This work was inspired from https://github.com/rpp0/gr-lora by Pieter Robyns, Peter Quax, Wim Lamotte and William Thenaers. Which architecture and functionalities have been improved to better emulate the physical layer of LoRa. This work also used the kiss FFT libary from github.com/mborgerding/kissfft for FFT operations. Finally, this code is a fork from github.com/tapparelj/gr-lora_sdr who made the original code.

Next to code this project is based on :

J. Tapparel, O. Afisiadis, P. Mayoraz, A. Balatsoukas-Stimming, and A. Burg, “An Open-Source LoRa Physical Layer Prototype on GNU Radio” [1]

Which can be found at arxiv.org/abs/2002.08208, if you find this implementation useful for your project, please consider citing the aforementioned paper.

Getting started

Documentation

• The documentation of the cpp source files can be found at docs and is automatically build from source using doxygen.
• The more practical and high level documentation along with examples can be found on the wiki

Installation

There is an Arch Linux package called gr-lora_sdr-git simply install it using your favourite aur helper. Similarly to any GNU Radio OOT module, it can be build using Cmake and make.

1. Clone the repo

   git clone https://github.com/martynvdijke/gr-lora_sdr

2. Enter the cloned directory

   cd gr-lora_sdr

3. Make build folder and enter it

   mkdir build && cd build

4. Configure cmake

   cmake ../ #-DCMAKE_INSTALL_PREFIX=/usr for Arch Linux users

5. Make install

   sudo make install

   You will need root or sudo access in order to properly install the repo, since it will add module blocks to be used in gnuradio-companian and makes a local python package. Be sure to have the following requirements installed:

Requirements

- Gnuradio 3.8
- python >2.7
- cmake >3.8
- swig  >4.0
- libvolk
- UHD 
- doxygen (optional for documentation)
- log4cpp (optional for logging/debugging)

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change. Make sure to add or update tests as appropriate.

Changelog

TODO

For TODO list checkout TODO

License

Distributed under the GPL-3.0 License License. See LICENSE for more information.