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prs resource mapping

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This commit is contained in:
ahadi
2021-11-30 20:08:40 +01:00
parent f136f047c0
commit a6fd470772
1 changed files with 63 additions and 7 deletions
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openair1/PHY/NR_TRANSPORT/nr_prs.c
+63 -7
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@@ -5,7 +5,8 @@
#include "PHY/NR_REFSIG/nr_refsig.h"
#include "PHY/sse_intrin.h"
#define DEBUG_PRS
//#define DEBUG_PRS
#define DEBUG_PRS_MAP
extern short nr_qpsk_mod_table[8];
@@ -15,14 +16,25 @@ int nr_generate_prs(uint32_t *nr_gold_prs,
uint8_t ssb_start_symbol,
nfapi_nr_config_request_scf_t *config,
NR_DL_FRAME_PARMS *frame_parms) {
//int k,l;
//int16_t a;
// Get K_Prime from the table for the length of PRS or LPRS
int k_prime_table[4][12] = {
{0,1,0,1,0,1,0,1,0,1,0,1},
{0,2,1,3,0,2,1,3,0,2,1,3},
{0,3,1,4,2,5,0,3,1,4,2,5},
{0,6,3,9,1,7,4,10,2,8,5,11}};
int k_prime = 0;
int k=0;
int16_t mod_prs[NR_MAX_PRS_LENGTH<<1];
uint8_t idx=0;
uint8_t nushift = config->cell_config.phy_cell_id.value &3;
LOG_D(PHY, "PRS mapping started at symbol %d shift %d\n", ssb_start_symbol+1, nushift);
/// QPSK modulation
uint8_t combSize = 6;
uint8_t REOffset = 0;
uint8_t symbolStart = 5;
uint8_t NumPRSSymbols = 6;
// QPSK modulation
for (int m=0; m<NR_MAX_PRS_LENGTH; m++) {
idx = (((nr_gold_prs[(m<<1)>>5])>>((m<<1)&0x1f))&3);
mod_prs[m<<1] = nr_qpsk_mod_table[idx<<1];
@@ -33,8 +45,52 @@ int nr_generate_prs(uint32_t *nr_gold_prs,
(((nr_gold_prs[((m<<1)+1)>>5])>>(((m<<1)+1)&0x1f))&1), mod_prs[(m<<1)], mod_prs[(m<<1)+1]);
#endif
}
// PRS resource mapping with combsize=k which means PRS symbols exist in every k-th subcarrier in frequency domain
// According to ts138.211 sec.7.4.1.7.2
for (int l = symbolStart; l < symbolStart + NumPRSSymbols; l++) {
int symInd = l-5;
if (combSize==2) {
k_prime = k_prime_table[0][symInd];
}
else if (combSize==4){
k_prime = k_prime_table[1][symInd];
}
else if (combSize==6){
k_prime = k_prime_table[2][symInd];
}
else if (combSize==12){
k_prime = k_prime_table[3][symInd];
}
for (int m = 0; m < NR_MAX_PRS_LENGTH; m++) {
#ifdef DEBUG_PRS_MAP
printf("m %d at k %d of l %d\n", m, k, l);
#endif
((int16_t *)txdataF)[(l*frame_parms->ofdm_symbol_size + k)<<1] = (amp * mod_prs[m<<1]) >> 15;
((int16_t *)txdataF)[((l*frame_parms->ofdm_symbol_size + k)<<1) + 1] = (amp * mod_prs[(m<<1) + 1]) >> 15;
#ifdef DEBUG_PRS_MAP
printf("(%d,%d)\n",
((int16_t *)txdataF)[(l*frame_parms->ofdm_symbol_size + k)<<1],
((int16_t *)txdataF)[((l*frame_parms->ofdm_symbol_size + k)<<1)+1]);
#endif
k=m*combSize+(REOffset+k_prime)%combSize;
//if (k >= frame_parms->ofdm_symbol_size)
//k-=frame_parms->ofdm_symbol_size;
}
}
return 0;
}