Commit graph

149 commits

Author SHA1 Message Date
Thomas Kolb b2d6c713e1 Briefly start in TX mode to ensure correct RX frequency
Obviously SoapyHackRF does not set the correct RX frequency on startup.
This is a crude but effective workaround.
2022-05-07 20:12:03 +02:00
Thomas Kolb ec99cedaf4 rx: improvements made during on-air testing
- limit frequency adjustment range
- pre-filter the baseband signal to remove out-of-band interference
- reset the frequency acquisition periodically (every 30s) if no preamble is found
2022-04-10 21:58:32 +02:00
Thomas Kolb 2d0bf7eeda sdr: fixed enumeration output 2022-04-08 16:17:17 +02:00
Thomas Kolb 96f10f7fb6 sdr: add gain configuration 2022-04-08 16:17:00 +02:00
Thomas Kolb 715cda83a8 RX: process samples in larger chunks 2022-04-07 21:17:37 +02:00
Thomas Kolb 3e74093fc7 Retry transmitting zeros 2022-04-07 20:58:08 +02:00
Thomas Kolb 31475907d3 Switch to IPv6 2022-04-07 20:44:07 +02:00
Thomas Kolb bfe27d3ead Added script for setting up the tun device 2022-04-07 20:34:21 +02:00
Thomas Kolb 47fc177e87 Reorganize Soapy stream management; flush tx buffer 2022-04-03 18:11:52 +02:00
Thomas Kolb 152d2f02f6 Basic transmitter-only main loop 2022-03-05 21:38:05 +01:00
Thomas Kolb 3bc1d9625f sdr: various fixes; use Kaiser filter for resampling 2022-03-05 21:37:33 +01:00
Thomas Kolb 85663d5304 Added SDR abstraction layer 2022-03-03 22:19:03 +01:00
Thomas Kolb 88145d74ba rx: added function to determine whether rx is busy 2022-03-01 21:51:41 +01:00
Thomas Kolb 45156e64a0 Show packets as hexdump instead of text 2022-02-27 22:01:51 +01:00
Thomas Kolb 9817896914 rx: make receiver more robust 2022-02-27 21:25:33 +01:00
Thomas Kolb 934b18e382 Integrate TUN device interface
Packets are now read from the TUN device and transmitted. The signal
goes through a channel emulator and is then received + decoded. If
decoding is successful, the result is written back to the TUN device
(which does not make much sense, but works for testing).

Unfortunately, there still seems to be a problem in the receiver: packet
loss is very high even at extremely high SNRs.
2022-02-27 20:21:14 +01:00
Thomas Kolb 890baf577f Moved config.h to src/ top level 2022-02-27 18:41:16 +01:00
Thomas Kolb 8a8ddc5ea3 rx: integrate AGC 2022-02-27 16:59:14 +01:00
Thomas Kolb a60b8b1f87 Moved results.h to src/ top level 2022-02-27 16:02:51 +01:00
Thomas Kolb 1787d0d351 layer1: implement per-packet modulation/coding
This allows a higher layer to adjust data rate based on the current
channel conditions. For example, the SNR could be measured and if it
becomes too low for the current modulation/code, a lower-order
modulation or stronger code could be used.
2022-02-17 21:39:18 +01:00
Thomas Kolb 0ed7109335 Clean up debug output 2022-02-16 21:46:56 +01:00
Thomas Kolb 876bafd6f9 Moved receiver to separate module 2022-02-16 20:52:46 +01:00
Thomas Kolb a5634ed736 Move the transmission chain to a separate "tx" module 2022-02-13 21:29:35 +01:00
Thomas Kolb 97772fa12b Removed unused packet_demod 2022-02-13 20:06:14 +01:00
Thomas Kolb 513a399ae4 Refactoring: moved layer1-related stuff to subdirectory 2022-02-13 20:05:47 +01:00
Thomas Kolb a124c04021 plot_spectrum: ensure that the t and f array sizes match 2022-02-13 19:54:07 +01:00
Thomas Kolb 89f04b3ad0 plot_constellation: added guard lines 2022-02-13 19:53:17 +01:00
Thomas Kolb eb3fc5f9c7 Use data whitening 2022-02-12 22:06:49 +01:00
Thomas Kolb 87b844a2da Implement CRC check and phase tracking 2022-02-12 21:58:53 +01:00
Thomas Kolb 947615f5cd First complete RX chain
Decoding of the test message works down to ~10 dB SNR.

Still missing:
- Phase tracking during header and payload.
- CRC calculation and check.
- Data whitening.
2022-02-11 17:56:26 +01:00
Thomas Kolb 042c05f9f3 Decode the received header 2022-02-10 22:33:51 +01:00
Thomas Kolb f2c95a125d Use new frequency+phase estimation method for preamble 2022-02-06 18:04:31 +01:00
Thomas Kolb 8060137c1d Move frequency estimation to separate module 2022-02-05 20:33:56 +01:00
Thomas Kolb 465d9a1c26 main: restructure state management; evaluate a found preamble 2022-02-03 22:18:24 +01:00
Thomas Kolb 423f1d6416 correlator: added functions for phase and frequency estimation 2022-02-03 22:17:37 +01:00
Thomas Kolb c17c7e060f Integrate preamble search 2022-02-01 21:35:43 +01:00
Thomas Kolb b6713909f7 Make initial frequency sync much faster
The NCO frequency is now only adjusted every 8 symbols. That means that
the frequency error over the last 8 symbols before the adjustment is
(almost) constant, giving a good estimation result. Therefore, the
adjustment factor can be much larger than previously, leading to faster
acquisition time.
2022-01-30 20:23:41 +01:00
Thomas Kolb c1dd039d6b First shot at frequency synchronization
Supports only the BPSK part so far (ramp-up, preamble).
2022-01-30 20:05:20 +01:00
Thomas Kolb 09465591ed Added symsync to the receiver chain 2022-01-29 22:37:55 +01:00
Thomas Kolb f983635c14 Fixed output size of transmission_filter_packet() 2022-01-29 22:14:25 +01:00
Thomas Kolb d522a1d6bd Implemented pulse shaping
The pulse shaper currently uses an RRC filter with beta=0.2.
2022-01-29 22:05:17 +01:00
Thomas Kolb a6fed80149 Added script for plotting the spectrum of signal dumps 2022-01-29 22:03:51 +01:00
Thomas Kolb a1f62a3b0a packet_mod: implement FEC and modulation for the header 2022-01-23 16:28:53 +01:00
Thomas Kolb 9a1107ff38 Added correlator + small test program 2022-01-22 22:42:05 +01:00
Thomas Kolb 6c21618f1f Document the packet_mod interface 2021-10-17 22:51:10 +02:00
Thomas Kolb 62ff2938ac Some python debug plot scripts 2021-10-17 19:46:30 +02:00
Thomas Kolb 874d8d5073 Fixed the modulator + test demodulation 2021-10-17 19:45:54 +02:00
Thomas Kolb 9ba470adeb Initial implementation of packet modulation
Not really tested yet…
2021-10-17 19:26:38 +02:00
Thomas Kolb 0b237a47cb Initial commit: infrastructure 2021-10-17 19:25:42 +02:00