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UL improved channel estimation around DC

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This commit is contained in:
Sakthivel Velumani
2019-11-08 10:27:06 +01:00
parent 9e7186c2cb
commit 497afe4f58
1 changed files with 66 additions and 1 deletions
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openair1/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c
+66 -1
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@@ -256,6 +256,71 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
ul_ch,
8);
// check if PRB crosses DC and improve estimates around DC
if ((bwp_start_subcarrier >= gNB->frame_parms.ofdm_symbol_size/2) && (bwp_start_subcarrier+nb_rb_pusch*12 >= gNB->frame_parms.ofdm_symbol_size)) {
ul_ch = (int16_t *)&ul_ch_estimates[aarx][ch_offset];
uint16_t idxDC = 2*(gNB->frame_parms.ofdm_symbol_size - bwp_start_subcarrier);
uint16_t idxPil = idxDC/2;
re_offset = k;
pil = (int16_t *)&pilot[0];
pil += (idxPil-4);
ul_ch += (idxDC-8);
ul_ch = memset(ul_ch, 0, sizeof(int16_t)*14);
re_offset = (re_offset+idxDC/2-4)&(gNB->frame_parms.ofdm_symbol_size-1);
rxF = (int16_t *)&rxdataF[aarx][(symbol_offset+nushift+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);
multadd_real_vector_complex_scalar(fl,
ch,
ul_ch,
8);
pil += 2;
re_offset = (re_offset+2)&(gNB->frame_parms.ofdm_symbol_size-1);
rxF = (int16_t *)&rxdataF[aarx][(symbol_offset+nushift+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);
multadd_real_vector_complex_scalar(filt8_dcl,
ch,
ul_ch,
8);
pil += 4;
re_offset = (re_offset+4)&(gNB->frame_parms.ofdm_symbol_size-1);
rxF = (int16_t *)&rxdataF[aarx][(symbol_offset+nushift+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);
multadd_real_vector_complex_scalar(filt8_dcr,
ch,
ul_ch,
8);
/*
pil += 2;
re_offset = (re_offset+2)&(gNB->frame_parms.ofdm_symbol_size-1);
rxF = (int16_t *)&rxdataF[aarx][(symbol_offset+nushift+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);
multadd_real_vector_complex_scalar(filt8_dcmd,
ch,
ul_ch,
8);
*/
}
#ifdef DEBUG_PDSCH
ul_ch = (int16_t *)&ul_ch_estimates[aarx][ch_offset];
for(uint16_t idxP=0; idxP<(nb_rb_pusch*12/8); idxP++) {
for(uint8_t idxI=0; idxI<16; idxI+=2) {
printf("%d\t%d\t",ul_ch[idxP*16+idxI],ul_ch[idxP*16+idxI+1]);
}
printf("\n");
}
#endif
// Convert to time domain
memset(temp_in_ifft_0, 0, gNB->frame_parms.ofdm_symbol_size*sizeof(int32_t));
memcpy(temp_in_ifft_0, &ul_ch_estimates[aarx][symbol_offset], nb_rb_pusch * NR_NB_SC_PER_RB * sizeof(int32_t));
@@ -322,4 +387,4 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
#endif
return(0);
}
}