From 107f20ad2912c351683ae139b62ce9e760fd5160 Mon Sep 17 00:00:00 2001 From: Thomas Schlichter Date: Mon, 18 Oct 2021 12:01:05 +0000 Subject: [PATCH] fix rounding in TA calculation --- openair1/SCHED_NR/phy_procedures_nr_gNB.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/openair1/SCHED_NR/phy_procedures_nr_gNB.c b/openair1/SCHED_NR/phy_procedures_nr_gNB.c index 63cf6f2f2d..1685e206ae 100644 --- a/openair1/SCHED_NR/phy_procedures_nr_gNB.c +++ b/openair1/SCHED_NR/phy_procedures_nr_gNB.c @@ -403,8 +403,6 @@ void nr_fill_indication(PHY_VARS_gNB *gNB, int frame, int slot_rx, int ULSCH_id, pthread_mutex_lock(&gNB->UL_INFO_mutex); - int timing_advance_update, cqi; - int sync_pos; NR_gNB_ULSCH_t *ulsch = gNB->ulsch[ULSCH_id][0]; NR_UL_gNB_HARQ_t *harq_process = ulsch->harq_processes[harq_pid]; NR_gNB_SCH_STATS_t *stats=get_ulsch_stats(gNB,ulsch); @@ -412,19 +410,20 @@ void nr_fill_indication(PHY_VARS_gNB *gNB, int frame, int slot_rx, int ULSCH_id, nfapi_nr_pusch_pdu_t *pusch_pdu = &harq_process->ulsch_pdu; // pdu->data = gNB->ulsch[ULSCH_id+1][0]->harq_processes[harq_pid]->b; - sync_pos = nr_est_timing_advance_pusch(gNB, ULSCH_id); // estimate timing advance for MAC + int sync_pos = nr_est_timing_advance_pusch(gNB, ULSCH_id); // estimate timing advance for MAC // scale the 16 factor in N_TA calculation in 38.213 section 4.2 according to the used FFT size uint16_t bw_scaling = 16 * gNB->frame_parms.ofdm_symbol_size / 2048; - int sync_pos_rounded; + // do some integer rounding to improve TA accuracy + int sync_pos_rounded; if (sync_pos > 0) sync_pos_rounded = sync_pos + (bw_scaling / 2) - 1; else - sync_pos_rounded = sync_pos - (bw_scaling / 2) - 1; + sync_pos_rounded = sync_pos - (bw_scaling / 2) + 1; if (stats) stats->sync_pos = sync_pos; - timing_advance_update = sync_pos_rounded / bw_scaling; + int timing_advance_update = sync_pos_rounded / bw_scaling; // put timing advance command in 0..63 range timing_advance_update += 31; @@ -449,6 +448,7 @@ void nr_fill_indication(PHY_VARS_gNB *gNB, int frame, int slot_rx, int ULSCH_id, LOG_D(PHY, "Estimated SNR for PUSCH is = %f dB (ulsch_power %f, noise %f)\n", SNRtimes10/10.0,dB_fixed_x10(gNB->pusch_vars[ULSCH_id]->ulsch_power_tot)/10.0,dB_fixed_x10(gNB->pusch_vars[ULSCH_id]->ulsch_noise_power_tot)/10.0); + int cqi; if (SNRtimes10 < -640) cqi=0; else if (SNRtimes10 > 635) cqi=255; else cqi=(640+SNRtimes10)/5;