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

NR UE scan for SSB within current bandwidth

Browse Source 
Till this commit, the UE gets the position of SSB in frequency from
command line and does the syncronization by locating the SSB in time. It
does this by generating a PSS time signal during initialization with the
SSB offset given via command line. Then PSS detection is done by
correlation.

In this commit, the UE computes a list of GSCN in the current NR band
that falls within the current bandwidth for the set center frequency.
For each GSCN in the list, the UE starts a thread and performs the
following:
1. Generate PSS time signal with SSB offset for current GSCN.
2. Detect PSS, SSS and decode PBCH (this step remains the same).
After all threads finishes, the results are collected.

For now, only the first detected PBCH is used to proceed further. So
this PBCH is indicated to MAC and UE exits initial sync.

Future work: The cell search can be standalone feature where the UE
could scan for SSB in the entire NR band. This would require changing
radio's frequency on the fly as the UE's bandwidth would not cover an
entire NR band. The cell detection can futher be imporved by looking
for SIB1 for each decoded PBCH.
This commit is contained in:
Sakthivel Velumani
2024-05-30 10:20:45 -04:00
parent 082007834c
commit 043da0c440
28 changed files with 845 additions and 570 deletions
Download Patch File Download Diff File Expand all files Collapse all files
openair1/PHY/MODULATION/modulation_UE.h
+3 -4
View File
@@ -61,12 +61,11 @@ int sl_nr_slot_fep(PHY_VARS_NR_UE *ue,
uint32_t sample_offset,
c16_t rxdataF[][ue->SL_UE_PHY_PARAMS.sl_frame_params.samples_per_slot_wCP]);
int nr_slot_fep_init_sync(PHY_VARS_NR_UE *ue,
const UE_nr_rxtx_proc_t *proc,
int nr_slot_fep_init_sync(const NR_DL_FRAME_PARMS *frame_parms,
unsigned char symbol,
int sample_offset,
bool pbch_decoded,
c16_t rxdataF[][ue->frame_parms.samples_per_slot_wCP],
const c16_t **rxdata,
c16_t rxdataF[][frame_parms->samples_per_slot_wCP],
int link_type);
int slot_fep_mbsfn(PHY_VARS_UE *phy_vars_ue,
openair1/PHY/MODULATION/slot_fep_nr.c
+12 -36
View File
@@ -203,31 +203,19 @@ int nr_slot_fep(PHY_VARS_NR_UE *ue,
return 0;
}
int nr_slot_fep_init_sync(PHY_VARS_NR_UE *ue,
const UE_nr_rxtx_proc_t *proc,
int nr_slot_fep_init_sync(const NR_DL_FRAME_PARMS *frame_parms,
unsigned char symbol,
int sample_offset,
bool pbch_decoded,
c16_t rxdataF[][ue->frame_parms.samples_per_slot_wCP],
const c16_t **rxdata,
c16_t rxdataF[][frame_parms->samples_per_slot_wCP],
int link_type)
{
NR_DL_FRAME_PARMS *frame_parms = &ue->frame_parms;
NR_UE_COMMON *common_vars = &ue->common_vars;
int Ns = proc->nr_slot_rx;
int Ns = 0;
AssertFatal(symbol < frame_parms->symbols_per_slot, "slot_fep: symbol must be between 0 and %d\n", frame_parms->symbols_per_slot-1);
AssertFatal(Ns < frame_parms->slots_per_frame, "slot_fep: Ns must be between 0 and %d\n", frame_parms->slots_per_frame-1);
unsigned int nb_prefix_samples;
unsigned int nb_prefix_samples0;
if (pbch_decoded) {
nb_prefix_samples = frame_parms->nb_prefix_samples;
nb_prefix_samples0 = frame_parms->nb_prefix_samples0;
}
else {
nb_prefix_samples = frame_parms->nb_prefix_samples;
nb_prefix_samples0 = frame_parms->nb_prefix_samples;
}
unsigned int nb_prefix_samples = frame_parms->nb_prefix_samples;
unsigned int frame_length_samples = frame_parms->samples_per_frame;
dft_size_idx_t dftsize = get_dft(frame_parms->ofdm_symbol_size);
@@ -236,10 +224,7 @@ int nr_slot_fep_init_sync(PHY_VARS_NR_UE *ue,
unsigned int slot_offset = frame_parms->get_samples_slot_timestamp(Ns,frame_parms,0);
unsigned int rx_offset = sample_offset + slot_offset;
unsigned int abs_symbol = Ns * frame_parms->symbols_per_slot + symbol;
for (int idx_symb = Ns*frame_parms->symbols_per_slot; idx_symb <= abs_symbol; idx_symb++)
rx_offset += (idx_symb%(0x7<<frame_parms->numerology_index)) ? nb_prefix_samples : nb_prefix_samples0;
rx_offset += frame_parms->ofdm_symbol_size * symbol;
rx_offset += (frame_parms->ofdm_symbol_size + nb_prefix_samples) * symbol + nb_prefix_samples;
#ifdef DEBUG_FEP
// if (ue->frame <100)
@@ -256,38 +241,29 @@ int nr_slot_fep_init_sync(PHY_VARS_NR_UE *ue,
// rxdata is 2 frames len
// we have to wrap on the end
memcpy((void *)&tmp_dft_in[0],
(void *)&common_vars->rxdata[aa][rx_offset],
(frame_length_samples*2 - rx_offset) * sizeof(int32_t));
memcpy((void *)&tmp_dft_in[frame_length_samples*2 - rx_offset],
(void *)&common_vars->rxdata[aa][0],
(frame_parms->ofdm_symbol_size - (frame_length_samples*2 - rx_offset)) * sizeof(int32_t));
memcpy((void *)&tmp_dft_in[0], (void *)&rxdata[aa][rx_offset], (frame_length_samples * 2 - rx_offset) * sizeof(int32_t));
memcpy((void *)&tmp_dft_in[frame_length_samples * 2 - rx_offset],
(void *)&rxdata[aa][0],
(frame_parms->ofdm_symbol_size - (frame_length_samples * 2 - rx_offset)) * sizeof(int32_t));
rxdata_ptr = (int16_t *)tmp_dft_in;
} else if ((rx_offset & 7) != 0) {
// if input to dft is not 256-bit aligned
memcpy((void *)&tmp_dft_in[0],
(void *)&common_vars->rxdata[aa][rx_offset],
frame_parms->ofdm_symbol_size * sizeof(int32_t));
memcpy((void *)&tmp_dft_in[0], (void *)&rxdata[aa][rx_offset], frame_parms->ofdm_symbol_size * sizeof(int32_t));
rxdata_ptr = (int16_t *)tmp_dft_in;
} else {
// use dft input from RX buffer directly
rxdata_ptr = (int16_t *)&common_vars->rxdata[aa][rx_offset];
rxdata_ptr = (int16_t *)&rxdata[aa][rx_offset];
}
start_meas(&ue->rx_dft_stats);
dft(dftsize,
rxdata_ptr,
(int16_t *)&rxdataF[aa][frame_parms->ofdm_symbol_size*symbol],
1);
stop_meas(&ue->rx_dft_stats);
int symb_offset = (Ns%frame_parms->slots_per_subframe)*frame_parms->symbols_per_slot;
c16_t rot2 = frame_parms->symbol_rotation[link_type][symbol + symb_offset];
rot2.i=-rot2.i;