renard-phy - Sigfox Protocol Physical Layer

renard-phy is an open source physical layer implementation of the Sigfox protocol's uplink and downlink written in Python for use with software defined radios (SDRs). It supports demodulating received Sigfox uplinks and downlinks recorded as WAV files (e.g. with gqrx and any SDR hardware that supports Sigfox's frequency range). Modulating uplink and downlink frames is supported for the HackRF One SDR.

renard-phy is built on top of renard, the CLI interface to the open source Sigfox protocol library librenard.

renard-phy has only been tested in regulatory zone "RCZ1" (Europe / ETSI).

Install / Dependencies

• renard-phy requires renard as a git submodule, so make sure to clone this repository recursively:

git clone --recursive https://github.com/Jeija/renard-phy

• Compile renard (see also renard's README)

cd renard
make
cd ..

• Install renard-phy's dependencies: NumPy, SciPy and matplotlib. If you wish to transmit frames with the HackRF One, make sure to install the HackRF drivers so that /usr/bin/hackrf_transfer exists.

Usage

Sample Recordings

If you want to try out renard-phy, but don't have recordings of Sigfox uplinks / downlinks, you can download sample WAV files.

Demodulation

Uplink

• Demodulate, do not decode:

$ cd renard-phy
$ ./uplink/demodulate.py uplink_4byte_zeros.wav
Estimating Frequency using 4096-length FFT
Signal Frequency: 2707.03 Hz
Mixing to Baseband with Costas Loop...
Low-pass Filtering...
Normalizing...
Finding Preamble(s)...
Found 3 Preambles!
[Frame 0]: Determining Frame Type...
[Frame 0]: Frame Type is 0x35f, Packet Length 12 bits
[Frame 0]: Content: 35f0088db334d000000000089b9c3e7
[Frame 0]: Decoding with renard:
[Frame 1]: Determining Frame Type...
[Frame 1]: Frame Type is 0x598, Packet Length 12 bits
[Frame 1]: Content: 59800ee806638c000000000ef0b52ed
[Frame 1]: Decoding with renard:
[Frame 2]: Determining Frame Type...
[Frame 2]: Frame Type is 0x5a3, Packet Length 12 bits
[Frame 2]: Content: 5a300aaedff9e4000000000abd7b31e
[Frame 2]: Decoding with renard:

• Demodulate and plot baseband signal, mark preambles:

$ ./uplink/demodulate.py uplink_4byte_zeros.wav --plot

• Demodulate and decode frame contents with renard (you can also do this manually by copy-pasting the frame content output):

$ ./uplink/demodulate.py uplink_4byte_zeros.wav --decode

Downlink

• Demodulate, do not decode:

$ ./downlink/demodulate.py downlink_0000000000000000.wav

• Demodulate and plot baseband signal, mark preamble:

$ ./downlink/demodulate.py downlink_0000000000000000.wav --plot

• Demodulate and brute-force-decode (other decoding options are available by manually copy-pasting the frame output for use with renard):

$ ./downlink/demodulate.py downlink_0000000000000000.wav --decode

Modulation and Transmission with HackRF One

The content (payload / device ID / SN / ...) of the transmitted frames is generated by renard. Command line arguments to the modulate_hackrf.py scripts are passed to renard, so see renard's documentation for a more extensive overview of possible command line options.

Uplink

• Transmit uplink with payload 0xabad1dea. Mind that all command line options to ./uplink/modulate_hackrf.py are simply forwarded to renard ulencode and renard's raw frame output is then converted to raw signals for transmission with the HackRF One.

$ ./uplink/modulate_hackrf.py -p abad1dea -s 1a0 -i 004d33db -k 479e4480fd7596d45b0122fd282db3cf

• You can also transmit uplinks with arbitrary frame contents using ./uplink/modulate_hackrf_hex.py by providing the binary frame content as hexadecimal string:

$ ./uplink/modulate_hackrf_hex.py aaaaa35f0001db334d00deadbeef68a60055

• You can even transmit multiple uplinks at different frequencies at the same time (frequency multiplexing) by providing all their hexadecimal frame contents to ./uplink/modulate_hackrf_hex_multiplex.py. The script will output a command that can be used to transmit the generated HackRF One sample file:

$ ./uplink/modulate_hackrf_hex_multiplex.py aaaaa35f0001db334d00deadbeef68a60055 aaaaa35f0002db334d00abad1dea7c74c0e0

Downlink

• Transmit downlink with payload 0xdeadbeef02468ace. The first parameter to ./downlink/modulate_hackrf.py is the frequency of the uplink that requested the downlink in Hz. This value is used to calculate the appropriate downlink frequency that the frame is transmitted at. All further command line options are simply forwareded to renard dlencode.

$ ./downlink/modulate_hackrf.py 868100000 -p deadbeef02468ace -i 004d33db -k 479e4480fd7596d45b0122fd282db3cf -s 1a1