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100 commits

Author SHA1 Message Date
Thomas Kolb 90ed7dc0a8 Re-add accidentally removed constants 2024-04-20 01:31:21 +02:00
Simon Ruderich 2768e21849 test_rx_file: set nco frequency 2024-04-20 01:14:17 +02:00
Simon Ruderich 79fc1c4f59 utils: fix numpy deprecation warnings 2024-04-20 01:14:17 +02:00
Thomas Kolb 7d1a927425 Calculate HackRF center frequency correctly 2024-04-20 01:07:21 +02:00
Thomas Kolb 32632914df Prevent TX exception in QPSK mode 
QPSK-modulated packets require more samples, which must be available in the TX
buffer. Therefore we increase the required free space.
 2024-04-20 01:04:13 +02:00
Thomas Kolb 11f19c03a0 Fix TX handling for multiple packets 
- (only) time-based end-of-transmission tracking
  - removed tx_done flag
  - count zero-buffers correctly in time-tracking
  - add 10 ms of headroom so the transmission does not stop before buffer was
    completely transmitted (race condition)
  - fix race condition with tx_start_time in sdr_start_tx()
- simplified packet queuing (no chunking)
- read multiple packets before starting transmission (to fill buffers initially)

Thanks to rudi_s!
 2024-04-20 00:55:39 +02:00
Thomas Kolb 1f5f922cdf Adjust squelch level and rampup 2024-04-12 21:50:49 +02:00
Thomas Kolb 91db4e1f75 rx: implement squelch + symsync reset 
Whenever the squelch opens, the symsync is reset to prevent lock-up in
that module due to noise.
 2024-04-08 22:03:09 +02:00
Thomas Kolb 4b46d87edb Add missing variable declaration 2024-03-31 22:26:34 +02:00
Thomas Kolb 93fd8aebbc Lock TX to RX frequency for clients 
Central nodes (“base stations”) do no longer do coarse frequency estimation,
but do only use the preamble + PLL for fine offset tracking.
 2024-03-31 22:23:04 +02:00
Thomas Kolb 4f4128fbd3 test: fixed build errors 2024-03-31 18:01:00 +02:00
Thomas Kolb 8441b12fbd rx: delay frequency estimation until history was fully refreshed 2024-03-30 22:10:13 +01:00
Thomas Kolb 171a4a369c rx: fix header checksum verification 2024-03-30 22:07:08 +01:00
Thomas Kolb 79d7f74dfc rx: use different PLL BW for header and data 2024-03-30 22:06:13 +01:00
Thomas Kolb bbf7bcf2f0 test/freq_est: add channel simulation 2024-03-30 22:05:02 +01:00
Thomas Kolb 66c88bf889 Improvements to debug scripts 2024-03-30 22:04:26 +01:00
Thomas Kolb d9707ac4a9 test: add test_rx_file 2024-03-30 21:56:00 +01:00
Thomas Kolb dd5712eada Add options parsing module 2024-03-30 21:51:27 +01:00
Thomas Kolb 07555edfdf Add CRC8 to the header 
This should prevent wrong decodings of modcod and packet length, which may disrupt decoding of directly following packets.
 2024-01-07 00:02:26 +01:00
Thomas Kolb 16aa2ce92c correlator: improved phase estimation 
The phase is now calculated based on the preamble correlation directly instead
of the method of the frequency estimator.
 2024-01-06 23:54:41 +01:00
Thomas Kolb ef25ca2388 Enable Hamming 8/4 code for the header 2024-01-05 21:29:41 +01:00
Thomas Kolb 84c172abc7 Fixed iterative frequency refinement; count header errors 2024-01-05 21:28:38 +01:00
Thomas Kolb 3a4be428b5 sdr: stop reading packets if the TX buffer is too full 2024-01-05 14:13:11 +01:00
Thomas Kolb e807f0617b rx: skip zero-length packets 
If passed on, these cause a segmentation fault in the channel decoder. As
zero-length packets currently make no real sense in this protocol, they are
ignored now.
 2024-01-05 13:49:50 +01:00
Thomas Kolb a6f12d876b sdr: fixed RX sample data conversion 2024-01-05 13:48:41 +01:00
Thomas Kolb be5fa06950 Handle SIGTERM and SIGINT for graceful shutdown 2024-01-03 22:03:19 +01:00
Thomas Kolb ee63483b8f sdr: scale sample for HackRF API 2024-01-03 17:41:35 +01:00
Thomas Kolb ac087634dd sdr: ensure that all samples were transmitted before TX is stopped 
This is done by tracking the time that the transmitter must stay on based on
the number of samples to be transmitted and the sampling rate.
 2024-01-03 17:32:51 +01:00
Thomas Kolb 8689ed5b27 Use fsleep instead of nanosleep 2024-01-03 17:29:51 +01:00
Thomas Kolb fb9c26ccd5 make.sh: allow passing parameters to make 2024-01-03 17:29:05 +01:00
Thomas Kolb 5564f1751a Fixed TX gain setting 2024-01-03 17:04:47 +01:00
Thomas Kolb c9d53ed96e Ensure that buffer is full when transmission starts 2024-01-03 00:33:54 +01:00
Thomas Kolb 628659511c sdr: properly flush the transmit buffers 2024-01-03 00:25:55 +01:00
Thomas Kolb 497498acd2 rx: fix overflow in symbol buffer 2024-01-03 00:01:27 +01:00
Thomas Kolb ef0fad4335 Improved handling of up- and downsampling 2024-01-02 23:49:55 +01:00
Thomas Kolb d55e3ab902 sdr: release buffered data; set sampling rate 2024-01-02 23:25:14 +01:00
Thomas Kolb 2b741acd8a Use libhackrf directly (not tested yet) 2024-01-02 22:49:16 +01:00
Thomas Kolb 7995f5bef0 Print RX stats periodically instead of debug logging 2024-01-02 19:04:19 +01:00
Thomas Kolb 112a8a1215 Improved logging and soapy stream handling 2023-05-20 22:01:26 +02:00
Thomas Kolb 2b078a4147 Settings updated: 2 Msps, 10 ms TX backoff 2023-05-20 21:59:40 +02:00
Thomas Kolb a6530da0d0 make.sh: set build type to RelWithDebInfo 2023-05-20 21:58:16 +02:00
Thomas Kolb f5a367464f Optimized one-shot frequency synchronization 
- Ramp-up length increased to 128 symbols (here is room for
  improvement!)
- Try to detect the frequency once during ramp-up. To do so, every
  second symbol is inverted (to remove the +/-1 symbol toggling) and the
  phase difference between neigboring resulting symbols is checked. When
  it is low enough for all symbols, the frequency is estimated and
  corrected. When frequency estimation was done, it is not retried for a
  number of incoming symbols in order to allow the timing estimator to
  converge again.
- This approach was verified in a simulated loopback test with frequency
  offset and AWGN.
 2023-05-17 22:28:18 +02:00
Thomas Kolb b5bae84994 utils: new and improved plotting scripts 2023-05-17 22:27:40 +02:00
Thomas Kolb a7db93ab9e Added test for frequency estimator 2023-05-17 22:26:46 +02:00
Thomas Kolb e42602633e freq_est: implement L&R-based symbol-independent frequency estimation 
The RX chain uses this to acquire an initial estimate of the carrier frequency. The estimate is adjusted on every incoming symbol until a preamble is found.
 2023-05-14 15:53:14 +02:00
Thomas Kolb 3b7628882c utils: open output file in binary mode 2023-05-12 13:49:20 +02:00
Thomas Kolb d17b7b3309 RX: added some asserts 2023-05-12 13:48:18 +02:00
Thomas Kolb afb25a69d8 Use dynamic linking for liquid-dsp again 2023-05-12 13:47:05 +02:00
Thomas Kolb 7d5b67a257 Add layer 1 software loopback test 2023-05-12 13:46:02 +02:00
Thomas Kolb c8e0516e80 Implement time-based carrier sensing 
In the following events, the modem cannot switch to transmit mode for the
given time:

- after a preamble has been received, for 500 ms
- after a packet has been successfully decoded, for 1 ms
- after receive mode was initially enabled, for 500 ms

Note that the times are that long to work around the RX/TX switching of
the hackrf and can be hopefully reduced to <10 milliseconds in a later
version.
 2022-05-07 21:17:53 +02:00