maki/openairinterface5g
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Merge remote-tracking branch 'origin/ntn_continuous_sib19_updates' into integration_2025_w27 (!3398)

Browse Source 
continuously update SIB19 information for rfsim NTN LEO scenarios

Contains mainly these changes:

- gNB: add function nr_update_sib19() allowing to update SIB19
  information
- rfsimulator: update SIB19 contents every frame for LEO channel
  simulations
- NR UE: improve initial timing advance calculation from SIB19

Before, we only considered ta_Common_r17 and the SAT position from SIB19
to compute the initial timing advance value. This is good enough if the
satellite does not move too fast (e.g. GEO satellite).

Now we also consider ta_CommonDrift_r17, ta_CommonDriftVariant_r17 and
the SAT velocity together with the epoch time from SIB19. This improves
the accuracy of the initial TA computation, esp. for LEO satellite
scenarios.
This commit is contained in:
Robert Schmidt
2025-07-04 09:42:19 +02:00
parent 105d4f6dfb 7b991c4dbf
commit 06a5166f17
17 changed files with 350 additions and 81 deletions
Download Patch File Download Diff File Expand all files Collapse all files
radio/rfsimulator/apply_channelmod.c
+38 -4
View File
@@ -25,6 +25,7 @@
#include <complex.h>
#include <common/utils/LOG/log.h>
#include <openair1/SIMULATION/TOOLS/sim.h>
#include "openair2/LAYER2/NR_MAC_gNB/mac_config.h"
#include "rfsimulator.h"
/*
@@ -95,7 +96,13 @@ void rxAddInput(const c16_t *input_sig,
const double vel_ue_sat = (vel_sat_x * dir_ue_sat_x + vel_sat_y * dir_ue_sat_y + vel_sat_z * dir_ue_sat_z) / dist_ue_sat;
double dist_sat_gnb = 0;
double vel_sat_gnb = 0;
double acc_sat_gnb = 0;
if (channelDesc->modelid == SAT_LEO_TRANS) {
const double acc_sat_x = 0;
const double acc_sat_y = -w_sat * w_sat * radius_sat * sin(w_sat * t);
const double acc_sat_z = -w_sat * w_sat * radius_sat * cos(w_sat * t);
const double pos_gnb_x = 0;
const double pos_gnb_y = 0;
const double pos_gnb_z = radius_earth;
@@ -105,6 +112,8 @@ void rxAddInput(const c16_t *input_sig,
const double dir_sat_gnb_z = pos_gnb_z - pos_sat_z;
dist_sat_gnb = sqrt(dir_sat_gnb_x * dir_sat_gnb_x + dir_sat_gnb_y * dir_sat_gnb_y + dir_sat_gnb_z * dir_sat_gnb_z);
vel_sat_gnb = (vel_sat_x * dir_sat_gnb_x + vel_sat_y * dir_sat_gnb_y + vel_sat_z * dir_sat_gnb_z) / dist_sat_gnb;
acc_sat_gnb = (acc_sat_x * dir_sat_gnb_x + acc_sat_y * dir_sat_gnb_y + acc_sat_z * dir_sat_gnb_z) / dist_sat_gnb;
}
const double prop_delay = (dist_ue_sat + dist_sat_gnb) / c;
@@ -117,8 +126,33 @@ void rxAddInput(const c16_t *input_sig,
if(TS - last_TS >= channelDesc->sampling_rate) {
last_TS = TS;
LOG_D(HW, "Satellite orbit: time %f s, Position = (%f, %f, %f), Velocity = (%f, %f, %f)\n", t, pos_sat_x, pos_sat_y, pos_sat_z, vel_sat_x, vel_sat_y, vel_sat_z);
LOG_D(HW, "Uplink delay %f ms, Doppler shift UE->SAT %f kHz\n", prop_delay * 1000, f_Doppler_shift_ue_sat / 1000);
LOG_I(HW, "Satellite orbit: time %f s, Position = (%f, %f, %f), Velocity = (%f, %f, %f)\n", t, pos_sat_x, pos_sat_y, pos_sat_z, vel_sat_x, vel_sat_y, vel_sat_z);
LOG_I(HW, "Uplink delay %f ms, Doppler shift UE->SAT %f kHz\n", prop_delay * 1000, f_Doppler_shift_ue_sat / 1000);
LOG_I(HW, "Satellite velocity towards gNB: %f m/s, acceleration towards gNB: %f m/s²\n", vel_sat_gnb, acc_sat_gnb);
}
const int samples_per_subframe = channelDesc->sampling_rate / 1000;
const int abs_subframe = TS / samples_per_subframe;
if (abs_subframe % 10 == 0) { // update SIB19 information for the next frame
gnb_sat_position_update_t sat_position = {
.sfn = (abs_subframe / 10 + 1) % 1024,
.subframe = 0,
.delay = 2 * dist_sat_gnb / (c * 4.072e-9),
.drift = 2 * -vel_sat_gnb / (c * 0.2e-9),
.accel = 2 * acc_sat_gnb / (c * 0.2e-10),
.position.X = pos_sat_x / 1.3,
.position.Y = pos_sat_y / 1.3,
.position.Z = pos_sat_z / 1.3,
.velocity.X = vel_sat_x / 0.06,
.velocity.Y = vel_sat_y / 0.06,
.velocity.Z = vel_sat_z / 0.06,
};
// Here we update the SIB19 information directly in the gNB MAC layer.
// Without rf-simulaor, in a real system or with an external channel emulator, the SIB19 updates would
// be provided via an external interface (e.g. O-RAN E2 interface) to the MAC layer (in the O-DU).
// We do it directly here, because we can, and an E2 Interface implementation (e.g using FlexRIC)
// would pull too many dependencies into rf-simulator, just for updating SIB19.
nr_update_sib19(&sat_position);
}
} else {
const double dir_sat_ue_x = pos_ue_x - pos_sat_x;
@@ -151,8 +185,8 @@ void rxAddInput(const c16_t *input_sig,
if(TS - last_TS >= channelDesc->sampling_rate) {
last_TS = TS;
LOG_D(HW, "Satellite orbit: time %f s, Position = (%f, %f, %f), Velocity = (%f, %f, %f)\n", t, pos_sat_x, pos_sat_y, pos_sat_z, vel_sat_x, vel_sat_y, vel_sat_z);
LOG_D(HW, "Downlink delay %f ms, Doppler shift SAT->UE %f kHz\n", prop_delay * 1000, f_Doppler_shift_sat_ue / 1000);
LOG_I(HW, "Satellite orbit: time %f s, Position = (%f, %f, %f), Velocity = (%f, %f, %f)\n", t, pos_sat_x, pos_sat_y, pos_sat_z, vel_sat_x, vel_sat_y, vel_sat_z);
LOG_I(HW, "Downlink delay %f ms, Doppler shift SAT->UE %f kHz\n", prop_delay * 1000, f_Doppler_shift_sat_ue / 1000);
}
}
}