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NR UE: add support for continuous UL frequency offset pre-compensation

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Depending on the main source of frequency offset, pre-compensate the UL frequency offset (FO) accordingly.
Therefore modify the flag `--cont-fo-comp` to accept an integer value, where
 - `1` specifies, that the main FO contribution comes from the accuracy of the local oscillator (LO)
 - `2` specifies, that the main FO contribution comes from Doppler shift
This commit is contained in:
Thomas Schlichter
2025-04-10 13:56:13 +00:00
parent aac4642910
commit 84712f5f92
3 changed files with 14 additions and 3 deletions
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executables/nr-ue.c
+10
View File
@@ -41,6 +41,7 @@
#include "instrumentation.h"
#include "common/utils/threadPool/notified_fifo.h"
#include "position_interface.h"
#include "nr_phy_common.h"
/*
* NR SLOT PROCESSING SEQUENCE
@@ -554,6 +555,15 @@ static void RU_write(nr_rxtx_thread_data_t *rxtxD, bool sl_tx_action)
writeBlockSize -= dummyBlockSize;
}
// pre-compensate UL frequency offset
if (flags != TX_BURST_INVALID && get_nrUE_params()->cont_fo_comp) {
double ul_freq_offset = -UE->freq_offset * ((double)fp->ul_CarrierFreq / (double)fp->dl_CarrierFreq);
if (get_nrUE_params()->cont_fo_comp == 2) // different from LO frequency error compensation, Doppler UL pre-compensation has to be negative
ul_freq_offset = -ul_freq_offset;
for (int i = 0; i < fp->nb_antennas_tx; i++)
nr_fo_compensation(ul_freq_offset, fp->samples_per_subframe, writeTimestamp, txp[i], writeBlockSize);
}
int tmp = openair0_write_reorder(&UE->rfdevice, writeTimestamp, txp, writeBlockSize, fp->nb_antennas_tx, flags);
AssertFatal(tmp == writeBlockSize, "");
}
executables/nr-uesoftmodem.h
+2 -2
View File
@@ -15,7 +15,7 @@
#define CONFIG_HLP_NTN_INIT_TIME_DRIFT "Initial NTN DL time drift (feeder link and service link), given in µs/s\n"
#define CONFIG_HLP_AUTONOMOUS_TA "Autonomously update TA based on DL drift (useful if main contribution to DL drift is movement, e.g. LEO satellite)\n"
#define CONFIG_HLP_INITIAL_FO "Initially compensated DL frequency offset (e.g. known Doppler shift in NTN LEO scenario)\n"
#define CONFIG_HLP_CONT_FO_COMP "Enable continuous frequency offset estimation and compensation\n"
#define CONFIG_HLP_CONT_FO_COMP "Enable continuous frequency offset (FO) estimation and compensation and specify main FO source (1 = local oscillator, 2 = Doppler shift)\n"
#define CONFIG_HLP_AGC "Rx Gain control used for UE\n"
/***************************************************************************************************************************************/
@@ -68,7 +68,7 @@
{"ntn-initial-time-drift", CONFIG_HLP_NTN_INIT_TIME_DRIFT, 0, .dblptr=&(nrUE_params.ntn_init_time_drift), .defdblval=0.0, TYPE_DOUBLE, 0}, \
{"autonomous-ta", CONFIG_HLP_AUTONOMOUS_TA, PARAMFLAG_BOOL, .iptr=&(nrUE_params.autonomous_ta), .defintval=0, TYPE_INT, 0}, \
{"initial-fo", CONFIG_HLP_INITIAL_FO, 0, .dblptr=&(nrUE_params.initial_fo), .defdblval=0.0, TYPE_DOUBLE, 0}, \
{"cont-fo-comp", CONFIG_HLP_CONT_FO_COMP, PARAMFLAG_BOOL, .iptr=&(nrUE_params.cont_fo_comp), .defintval=0, TYPE_INT, 0}, \
{"cont-fo-comp", CONFIG_HLP_CONT_FO_COMP, 0, .iptr=&(nrUE_params.cont_fo_comp), .defintval=0, TYPE_INT, 0}, \
{"agc", CONFIG_HLP_AGC, PARAMFLAG_BOOL, .iptr=&(nrUE_params.agc), .defintval=0, TYPE_INT, 0}, \
}
// clang-format on