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Fix FR2 SSB start subcarrier and SSB frequency at gNB

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for FR2 offsetToPointA is expressed in terms of 60 kHz SCS and k_SSB expressed in terms of the subcarrier spacing provided by the higher-layer parameter subCarrierSpacingCommon
This commit is contained in:
luis_pereira87
2024-02-14 13:13:42 +00:00
parent c78399ee36
commit 3d8b38f7e6
2 changed files with 25 additions and 13 deletions
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openair1/SCHED_NR/phy_procedures_nr_gNB.c
+17 -5
View File
@@ -70,13 +70,25 @@ void nr_common_signal_procedures (PHY_VARS_gNB *gNB,int frame,int slot,nfapi_nr_
int ssb_start_symbol_abs = nr_get_ssb_start_symbol(fp,ssb_index); // computing the starting symbol for current ssb
ssb_start_symbol = ssb_start_symbol_abs % fp->symbols_per_slot; // start symbol wrt slot
// setting the first subcarrier
// Setting the first subcarrier
// 3GPP TS 38.211 sections 7.4.3.1 and 4.4.4.2
// for FR1 offsetToPointA and k_SSB are expressed in terms of 15 kHz SCS
// for FR2 offsetToPointA is expressed in terms of 60 kHz SCS and k_SSB expressed in terms of the subcarrier spacing provided
// by the higher-layer parameter subCarrierSpacingCommon
const int scs = cfg->ssb_config.scs_common.value;
const int prb_offset = (fp->freq_range == nr_FR1) ? ssb_pdu.ssb_pdu_rel15.ssbOffsetPointA>>scs : ssb_pdu.ssb_pdu_rel15.ssbOffsetPointA>>(scs-2);
const int sc_offset = (fp->freq_range == nr_FR1) ? ssb_pdu.ssb_pdu_rel15.SsbSubcarrierOffset >> scs
: ssb_pdu.ssb_pdu_rel15.SsbSubcarrierOffset >> (scs - 2);
const int prb_offset = (fp->freq_range == nr_FR1) ? ssb_pdu.ssb_pdu_rel15.ssbOffsetPointA >> scs
: ssb_pdu.ssb_pdu_rel15.ssbOffsetPointA >> (scs - 2);
const int sc_offset =
(fp->freq_range == nr_FR1) ? ssb_pdu.ssb_pdu_rel15.SsbSubcarrierOffset >> scs : ssb_pdu.ssb_pdu_rel15.SsbSubcarrierOffset;
fp->ssb_start_subcarrier = (12 * prb_offset + sc_offset);
LOG_D(PHY, "SSB first subcarrier %d (%d,%d)\n", fp->ssb_start_subcarrier, prb_offset, sc_offset);
LOG_D(PHY,
"ssbOffsetPointA %d SSB SsbSubcarrierOffset %d prb_offset %d sc_offset %d scs %d ssb_start_subcarrier %d\n",
ssb_pdu.ssb_pdu_rel15.ssbOffsetPointA,
ssb_pdu.ssb_pdu_rel15.SsbSubcarrierOffset,
prb_offset,
sc_offset,
scs,
fp->ssb_start_subcarrier);
LOG_D(PHY,"SS TX: frame %d, slot %d, start_symbol %d\n",frame,slot, ssb_start_symbol);
nr_generate_pss(&txdataF[0][txdataF_offset], gNB->TX_AMP, ssb_start_symbol, cfg, fp);
openair2/RRC/NR/rrc_gNB.c
+8 -8
View File
@@ -197,21 +197,21 @@ static int get_ssb_arfcn(const f1ap_served_cell_info_t *cell_info, const NR_MIB_
uint32_t dl_arfcn = get_dl_arfcn(cell_info);
int scs = get_ssb_scs(cell_info);
int band = get_dl_band(cell_info);
uint64_t freqpointa = from_nrarfcn(band, scs, dl_arfcn);
uint64_t freqssb = 0;
// 3GPP TS 38.211 sections 7.4.3.1 and 4.4.4.2
// for FR1 offsetToPointA and k_SSB are expressed in terms of 15 kHz SCS
// for FR2 offsetToPointA is expressed in terms of 60 kHz SCS and k_SSB expressed in terms of the subcarrier spacing provided
// by the higher-layer parameter subCarrierSpacingCommon
// FR1 includes frequency bands from 410 MHz (ARFCN 82000) to 7125 MHz (ARFCN 875000)
// FR2 includes frequency bands from 24.25 GHz (ARFCN 2016667) to 71.0 GHz (ARFCN 2795832)
uint64_t scaling = 0;
if (dl_arfcn >= 82000 && dl_arfcn < 875000)
scaling = 1;
freqssb = freqpointa + 15000 * (offsetToPointA * 12 + kssb) + 10ll * 12 * (1 << scs) * 15000;
else if (dl_arfcn >= 2016667 && dl_arfcn < 2795832)
scaling = 4;
freqssb = freqpointa + 60000 * offsetToPointA * 12 + (1 << scs) * 15000 * (kssb + 10ll * 12);
else
AssertFatal(false, "Invalid absoluteFrequencyPointA: %d\n", dl_arfcn);
uint64_t freqpointa = from_nrarfcn(band, scs, dl_arfcn);
// offsetToPointA and kSSB are both on 15kHz SCS for FR1 and 60kHz SCS for FR2 (see 38.211 sections 7.4.3.1 and 4.4.4.2)
// SSB uses the SCS of the cell and is 20 RBs wide, so use 10
uint64_t freqssb = freqpointa + scaling * 15000 * (offsetToPointA * 12 + kssb) + 10ll * 12 * (1 << scs) * 15000;
int bw_index = get_supported_band_index(scs, band, get_dl_bw(cell_info));
int band_size_hz = get_supported_bw_mhz(band > 256 ? FR2 : FR1, bw_index) * 1000 * 1000;
uint32_t ssb_arfcn = to_nrarfcn(band, freqssb, scs, band_size_hz);