From b533127553bd395168b20eb8d7ed412d9b7d6eef Mon Sep 17 00:00:00 2001 From: Robert Schmidt Date: Thu, 15 Jan 2026 16:11:06 +0100 Subject: [PATCH 1/4] Ensure noise power is non-zero Prior to this commit, noise power estimation could be zero because of a call to clearArray() in gNB_I0_measurements(). This is problematic, as this can lead to a noise power of 0 if all symbols in a RB are used, which in turn leads to a spike in SNR. To avoid this, use an intermediate array to store noise power, and only update n0_subband_power if not all RBs are used (i.e., we can detect noise power). Further, use an exponential moving average to smoothen noise estimation. Fixes: fb4235fd50e9 ("changes in PUCCH0 SNR measurement, testing for PUCCH power control") --- .../PHY/NR_ESTIMATION/nr_measurements_gNB.c | 36 ++++++++++--------- 1 file changed, 20 insertions(+), 16 deletions(-) diff --git a/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c b/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c index 89aba954e9..a14e903a3e 100644 --- a/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c +++ b/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c @@ -144,19 +144,8 @@ void gNB_I0_measurements(PHY_VARS_gNB *gNB, int slot, int first_symb, int num_sy PHY_MEASUREMENTS_gNB *measurements = &gNB->measurements; int nb_symb[275]={0}; - allocCast2D(n0_subband_power, - unsigned int, - gNB->measurements.n0_subband_power, - frame_parms->nb_antennas_rx, - frame_parms->N_RB_UL, - false); - clearArray(gNB->measurements.n0_subband_power, unsigned int); - allocCast2D(n0_subband_power_dB, - unsigned int, - gNB->measurements.n0_subband_power_dB, - frame_parms->nb_antennas_rx, - frame_parms->N_RB_UL, - false); + unsigned int tmp_n0_subband[frame_parms->nb_antennas_rx][frame_parms->N_RB_UL]; + memset(tmp_n0_subband, 0, sizeof(tmp_n0_subband)); // TODO modify the measurements to take into account concurrent beams for (int s = first_symb; s < first_symb + num_symb; s++) { @@ -176,7 +165,8 @@ void gNB_I0_measurements(PHY_VARS_gNB *gNB, int slot, int first_symb, int num_sy } else { signal_energy = signal_energy_nodc(ul_ch, 12); } - n0_subband_power[aarx][rb] += signal_energy; + // noise power per antenna/RB, symbols summed up + tmp_n0_subband[aarx][rb] += signal_energy; LOG_D(NR_PHY,"slot %d symbol %d RB %d aarx %d n0_subband_power %d\n", slot, s, rb, aarx, signal_energy); } //antenna } @@ -185,14 +175,28 @@ void gNB_I0_measurements(PHY_VARS_gNB *gNB, int slot, int first_symb, int num_sy int nb_rb=0; int64_t n0_subband_tot=0; int32_t n0_subband_tot_perANT[frame_parms->nb_antennas_rx]; - memset(n0_subband_tot_perANT, 0, sizeof(n0_subband_tot_perANT)); + allocCast2D(n0_subband_power, + unsigned int, + gNB->measurements.n0_subband_power, + frame_parms->nb_antennas_rx, + frame_parms->N_RB_UL, + false); + allocCast2D(n0_subband_power_dB, + unsigned int, + gNB->measurements.n0_subband_power_dB, + frame_parms->nb_antennas_rx, + frame_parms->N_RB_UL, + false); + for (int rb = 0 ; rbN_RB_UL;rb++) { int32_t n0_subband_tot_perPRB=0; if (nb_symb[rb] > 0) { for (int aarx=0;aarxnb_antennas_rx;aarx++) { - n0_subband_power[aarx][rb] /= nb_symb[rb]; + tmp_n0_subband[aarx][rb] /= nb_symb[rb]; + // apply exponential moving average to smooth noise measurements + n0_subband_power[aarx][rb] = 0.9 * n0_subband_power[aarx][rb] + 0.1 * tmp_n0_subband[aarx][rb]; n0_subband_power_dB[aarx][rb] = dB_fixed(n0_subband_power[aarx][rb]); n0_subband_tot_perPRB += n0_subband_power[aarx][rb]; n0_subband_tot_perANT[aarx] += n0_subband_power[aarx][rb]; From 656b1d52a008013cb28b6182836e9a0e62b7fc22 Mon Sep 17 00:00:00 2001 From: Laurent THOMAS Date: Wed, 4 Feb 2026 19:04:00 +0100 Subject: [PATCH 2/4] Remove unused global variables --- openair1/PHY/INIT/nr_init.c | 1 - openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c | 14 +++----------- openair1/PHY/defs_gNB.h | 4 ---- 3 files changed, 3 insertions(+), 16 deletions(-) diff --git a/openair1/PHY/INIT/nr_init.c b/openair1/PHY/INIT/nr_init.c index ad92ae6c34..1615fc86f3 100644 --- a/openair1/PHY/INIT/nr_init.c +++ b/openair1/PHY/INIT/nr_init.c @@ -228,7 +228,6 @@ void phy_free_nr_gNB(PHY_VARS_gNB *gNB) PHY_MEASUREMENTS_gNB *meas = &gNB->measurements; free_and_zero(meas->n0_subband_power); - free_and_zero(meas->n0_subband_power_dB); for (int id = 0; id < gNB->max_nb_srs; id++) { for(int i=0; imeasurements.n0_subband_power, - frame_parms->nb_antennas_rx, - frame_parms->N_RB_UL, - false); - allocCast2D(n0_subband_power_dB, - unsigned int, - gNB->measurements.n0_subband_power_dB, + measurements->n0_subband_power, frame_parms->nb_antennas_rx, frame_parms->N_RB_UL, false); @@ -193,17 +187,15 @@ void gNB_I0_measurements(PHY_VARS_gNB *gNB, int slot, int first_symb, int num_sy for (int rb = 0 ; rbN_RB_UL;rb++) { int32_t n0_subband_tot_perPRB=0; if (nb_symb[rb] > 0) { - for (int aarx=0;aarxnb_antennas_rx;aarx++) { + for (int aarx = 0; aarx < frame_parms->nb_antennas_rx; aarx++) { tmp_n0_subband[aarx][rb] /= nb_symb[rb]; // apply exponential moving average to smooth noise measurements n0_subband_power[aarx][rb] = 0.9 * n0_subband_power[aarx][rb] + 0.1 * tmp_n0_subband[aarx][rb]; - n0_subband_power_dB[aarx][rb] = dB_fixed(n0_subband_power[aarx][rb]); n0_subband_tot_perPRB += n0_subband_power[aarx][rb]; n0_subband_tot_perANT[aarx] += n0_subband_power[aarx][rb]; } - n0_subband_tot_perPRB/=frame_parms->nb_antennas_rx; + n0_subband_tot_perPRB /= frame_parms->nb_antennas_rx; measurements->n0_subband_power_tot_dB[rb] = dB_fixed(n0_subband_tot_perPRB); - measurements->n0_subband_power_tot_dBm[rb] = measurements->n0_subband_power_tot_dB[rb] - gNB->rx_total_gain_dB - dB_fixed(frame_parms->N_RB_UL); LOG_D(NR_PHY,"n0_subband_power_tot_dB[%d] => %d, over %d symbols\n",rb,measurements->n0_subband_power_tot_dB[rb],nb_symb[rb]); n0_subband_tot += n0_subband_tot_perPRB; nb_rb++; diff --git a/openair1/PHY/defs_gNB.h b/openair1/PHY/defs_gNB.h index 46ba246dbe..62860283d9 100644 --- a/openair1/PHY/defs_gNB.h +++ b/openair1/PHY/defs_gNB.h @@ -340,16 +340,12 @@ typedef struct { unsigned int n0_power_tot_dB; //! estimated avg noise power per RB per RX ant (lin) fourDimArray_t *n0_subband_power; - //! estimated avg noise power per RB per RX ant (dB) - fourDimArray_t *n0_subband_power_dB; //! estimated avg subband noise power (dB) unsigned int n0_subband_power_avg_dB; //! estimated avg subband noise power per antenna (dB) unsigned int n0_subband_power_avg_perANT_dB[MAX_ANT]; //! estimated avg noise power per RB (dB) int n0_subband_power_tot_dB[275]; - //! estimated avg noise power per RB (dBm) - int n0_subband_power_tot_dBm[275]; /// PRACH background noise level int prach_I0; } PHY_MEASUREMENTS_gNB; From ee00eb346e1b761a166baa21c23e51083a65145a Mon Sep 17 00:00:00 2001 From: Laurent THOMAS Date: Wed, 4 Feb 2026 19:11:10 +0100 Subject: [PATCH 3/4] Reformat dump_nr_I0_stats() --- .../PHY/NR_ESTIMATION/nr_measurements_gNB.c | 65 +++++++++++-------- openair1/PHY/NR_TRANSPORT/nr_ulsch.h | 2 - 2 files changed, 38 insertions(+), 29 deletions(-) diff --git a/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c b/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c index fc190c4542..6005c39343 100644 --- a/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c +++ b/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c @@ -105,36 +105,47 @@ void nr_est_srs_timing_advance_offset(uint16_t ofdm_symbol_size, max_idx); } -void dump_nr_I0_stats(FILE *fd,PHY_VARS_gNB *gNB) { - - - int min_I0=1000,max_I0=0; - int amin=0,amax=0; - fprintf(fd,"Blacklisted PRBs %d/%d\n",gNB->num_ulprbbl,gNB->frame_parms.N_RB_UL); - for (int i=0; iframe_parms.N_RB_UL; i++) { - if (gNB->ulprbbl[i] > 0) continue; - - if (gNB->measurements.n0_subband_power_tot_dB[i]measurements.n0_subband_power_tot_dB[i]; amin=i;} - - if (gNB->measurements.n0_subband_power_tot_dB[i]>max_I0) {max_I0 = gNB->measurements.n0_subband_power_tot_dB[i]; amax=i;} +void dump_nr_I0_stats(FILE *fd, PHY_VARS_gNB *gNB) +{ + int min_I0 = 1000, max_I0 = 0; + int amin = 0, amax = 0; + fprintf(fd, "Blacklisted PRBs %d/%d\n", gNB->num_ulprbbl, gNB->frame_parms.N_RB_UL); + for (int i = 0; i < gNB->frame_parms.N_RB_UL; i++) { + if (gNB->ulprbbl[i] > 0) + continue; + if (gNB->measurements.n0_subband_power_tot_dB[i] < min_I0) { + min_I0 = gNB->measurements.n0_subband_power_tot_dB[i]; + amin = i; } - - for (int i=0; iframe_parms.N_RB_UL; i++) { - if (gNB->ulprbbl[i] ==0) fprintf(fd,"%2d.",gNB->measurements.n0_subband_power_tot_dB[i]-gNB->measurements.n0_subband_power_avg_dB); - else fprintf(fd," X."); - if (i%25 == 24) fprintf(fd,"\n"); + if (gNB->measurements.n0_subband_power_tot_dB[i] > max_I0) { + max_I0 = gNB->measurements.n0_subband_power_tot_dB[i]; + amax = i; } - fprintf(fd,"\n"); - fprintf(fd,"max_IO = %d (%d), min_I0 = %d (%d), avg_I0 = %d dB",max_I0,amax,min_I0,amin,gNB->measurements.n0_subband_power_avg_dB); - if (gNB->frame_parms.nb_antennas_rx>1) { - fprintf(fd,"("); - for (int aarx=0;aarxframe_parms.nb_antennas_rx;aarx++) - fprintf(fd,"%d.",gNB->measurements.n0_subband_power_avg_perANT_dB[aarx]); - fprintf(fd,")"); - } - fprintf(fd,"\nPRACH I0 = %d.%d dB\n",gNB->measurements.prach_I0/10,gNB->measurements.prach_I0%10); - + } + for (int i = 0; i < gNB->frame_parms.N_RB_UL; i++) { + if (gNB->ulprbbl[i] == 0) + fprintf(fd, "%2d.", gNB->measurements.n0_subband_power_tot_dB[i] - gNB->measurements.n0_subband_power_avg_dB); + else + fprintf(fd, " X."); + if (i % 25 == 24) + fprintf(fd, "\n"); + } + fprintf(fd, "\n"); + fprintf(fd, + "max_IO = %d (%d), min_I0 = %d (%d), avg_I0 = %d dB", + max_I0, + amax, + min_I0, + amin, + gNB->measurements.n0_subband_power_avg_dB); + if (gNB->frame_parms.nb_antennas_rx > 1) { + fprintf(fd, "("); + for (int aarx = 0; aarx < gNB->frame_parms.nb_antennas_rx; aarx++) + fprintf(fd, "%d.", gNB->measurements.n0_subband_power_avg_perANT_dB[aarx]); + fprintf(fd, ")"); + } + fprintf(fd, "\nPRACH I0 = %d.%d dB\n", gNB->measurements.prach_I0 / 10, gNB->measurements.prach_I0 % 10); } void gNB_I0_measurements(PHY_VARS_gNB *gNB, int slot, int first_symb, int num_symb, uint32_t rb_mask_ul[14][9]) diff --git a/openair1/PHY/NR_TRANSPORT/nr_ulsch.h b/openair1/PHY/NR_TRANSPORT/nr_ulsch.h index 95474f64c0..0f66e49ff6 100644 --- a/openair1/PHY/NR_TRANSPORT/nr_ulsch.h +++ b/openair1/PHY/NR_TRANSPORT/nr_ulsch.h @@ -74,8 +74,6 @@ void nr_ulsch_layer_demapping(int16_t *llr_cw, uint8_t Nl, uint8_t mod_order, ui void dump_pusch_stats(FILE *fd,PHY_VARS_gNB *gNB); -void dump_nr_I0_stats(FILE *fd,PHY_VARS_gNB *gNB); - NR_gNB_SCH_STATS_t *get_ulsch_stats(PHY_VARS_gNB *gNB,NR_gNB_ULSCH_t *ulsch); #endif /* NR_ULSCH_H_ */ From 74b998a0d8c8a2b9f9cc1e17a66e6d75a3dea316 Mon Sep 17 00:00:00 2001 From: Laurent THOMAS Date: Wed, 4 Feb 2026 19:20:38 +0100 Subject: [PATCH 4/4] Rewrite n0_subband_power_avg_dB calculation with better locality --- openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c b/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c index 6005c39343..c11741eb40 100644 --- a/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c +++ b/openair1/PHY/NR_ESTIMATION/nr_measurements_gNB.c @@ -184,7 +184,6 @@ void gNB_I0_measurements(PHY_VARS_gNB *gNB, int slot, int first_symb, int num_sy } //rb } // symb int nb_rb=0; - int64_t n0_subband_tot=0; int32_t n0_subband_tot_perANT[frame_parms->nb_antennas_rx]; memset(n0_subband_tot_perANT, 0, sizeof(n0_subband_tot_perANT)); @@ -208,14 +207,15 @@ void gNB_I0_measurements(PHY_VARS_gNB *gNB, int slot, int first_symb, int num_sy n0_subband_tot_perPRB /= frame_parms->nb_antennas_rx; measurements->n0_subband_power_tot_dB[rb] = dB_fixed(n0_subband_tot_perPRB); LOG_D(NR_PHY,"n0_subband_power_tot_dB[%d] => %d, over %d symbols\n",rb,measurements->n0_subband_power_tot_dB[rb],nb_symb[rb]); - n0_subband_tot += n0_subband_tot_perPRB; nb_rb++; } } if (nb_rb>0) { - measurements->n0_subband_power_avg_dB = dB_fixed(n0_subband_tot/nb_rb); - for (int aarx=0;aarxnb_antennas_rx;aarx++) { - measurements->n0_subband_power_avg_perANT_dB[aarx] = dB_fixed(n0_subband_tot_perANT[aarx]/nb_rb); - } + int64_t n0_subband_tot = 0; + for (int aarx = 0; aarx < frame_parms->nb_antennas_rx; aarx++) { + measurements->n0_subband_power_avg_perANT_dB[aarx] = dB_fixed(n0_subband_tot_perANT[aarx] / nb_rb); + n0_subband_tot += n0_subband_tot_perANT[aarx]; + } + measurements->n0_subband_power_avg_dB = dB_fixed(n0_subband_tot / nb_rb); } }