From 497afe4f58afdb8acdeb36be6068ac25fa5c21ef Mon Sep 17 00:00:00 2001 From: Sakthivel Velumani <sakthivel.velumani@eurecom.fr> Date: Fri, 8 Nov 2019 10:27:06 +0100 Subject: [PATCH] UL improved channel estimation around DC --- .../NR_ESTIMATION/nr_ul_channel_estimation.c | 67 ++++++++++++++++++- 1 file changed, 66 insertions(+), 1 deletion(-) diff --git a/openair1/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c b/openair1/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c index 0656091c78..c5a47e6a22 100644 --- a/openair1/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c +++ b/openair1/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c @@ -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); -} \ No newline at end of file +} -- 2.26.2