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Improvements in UL channel estimation to consider multiple antennas for dmrs type 1

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This commit is contained in:
Roberto Louro Magueta
2022-04-29 00:51:55 +01:00
parent 724e155a3a
commit 719d7fb8be
1 changed files with 20 additions and 14 deletions
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openair1/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c
+20 -14
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@@ -246,33 +246,41 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
LOG_I(PHY, "In %s ul_ch addr %p nushift %d\n", __FUNCTION__, ul_ch, nushift);
#endif
if (pusch_pdu->dmrs_config_type == pusch_dmrs_type1 && gNB->prb_interpolation == 0){
if (pusch_pdu->dmrs_config_type == pusch_dmrs_type1 && gNB->prb_interpolation == 0) {
LOG_D(PHY,"PUSCH estimation DMRS type 1, Freq-domain interpolation");
// For configuration type 1: k = 4*n + 2*k' + delta,
// where k' is 0 or 1, and delta is in Table 6.4.1.1.3-1 from TS 38.211
int delta = nr_pusch_dmrs_delta(pusch_dmrs_type1, p);
pilot_cnt = 0;
for (int n = 0; n < 3*nb_rb_pusch; n++) {
// LS estimation
ch[0] = 0;
ch[1] = 0;
for (int p2 = 0; p2<pusch_pdu->nrOfLayers; p2+=2) {
int delta2 = nr_pusch_dmrs_delta(pusch_dmrs_type1, p2);
for (int k_line = 0; k_line <= 1; k_line++) {
re_offset = (k0 + (n << 2) + (k_line << 1) + delta2) % gNB->frame_parms.ofdm_symbol_size;
rxF = (int16_t *) &rxdataF[aarx][(soffset + symbol_offset + re_offset)];
ch[0] += (int16_t) (((int32_t) pil[0] * rxF[0] - (int32_t) pil[1] * rxF[1]) >> 15);
ch[1] += (int16_t) (((int32_t) pil[0] * rxF[1] + (int32_t) pil[1] * rxF[0]) >> 15);
pil += 2;
}
}
// Channel interpolation
for (int k_line = 0; k_line <= 1; k_line++) {
pilot_cnt++;
re_offset = (k0 + (n<<2) + (k_line<<1) + delta) % gNB->frame_parms.ofdm_symbol_size;
rxF = (int16_t *)&rxdataF[aarx][(soffset + symbol_offset + re_offset)];
ch[0] = (int16_t)(((int32_t)pil[0]*rxF[0] - (int32_t)pil[1]*rxF[1])>>15);
ch[1] = (int16_t)(((int32_t)pil[0]*rxF[1] + (int32_t)pil[1]*rxF[0])>>15);
#ifdef DEBUG_PUSCH
re_offset = (k0 + (n << 2) + (k_line << 1)) % gNB->frame_parms.ofdm_symbol_size;
rxF = (int16_t *) &rxdataF[aarx][(soffset + symbol_offset + re_offset)];
printf("pilot %4u: pil -> (%6d,%6d), rxF -> (%4d,%4d), ch -> (%4d,%4d)\n",
pilot_cnt, pil[0], pil[1], rxF[0], rxF[1], ch[0], ch[1]);
//printf("data %4u: rxF -> (%4d,%4d) (%2d)\n",pilot_cnt, rxF[2], rxF[3], dBc(rxF[2], rxF[3]));
#endif
if (pilot_cnt == 0) {
multadd_real_vector_complex_scalar(fl, ch, ul_ch, 8);
} else if (pilot_cnt == 1) {
@@ -288,8 +296,6 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
} else {
multadd_real_vector_complex_scalar(fm, ch, ul_ch, 8);
}
pil += 2;
}
}