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OpenXG-RAN
Commit ef3be740 authored by Thomas Schlichter's avatar Thomas Schlichter
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Fix channel estimation for 3/4 sampling 

In 3/4 sampling mode, the OFDM symbol size is _not_ a power of two (e.g. 1536 instead of 2048).
In this case it is _not_ OK to calculate the modulus using a binary AND, it _must_ use either the actul modulus operator (%) using an integer division,
or a _correct_ if statement or tertianary operator like this:

re_offset = (re_offset + 4 >= ue->frame_parms.ofdm_symbol_size) ? (re_offset + 4 - ue->frame_parms.ofdm_symbol_size) : (re_offset + 4);

But of course using the actual modulus operator is much more readable and surely not much slower:

re_offset = (re_offset + 4) % ue->frame_parms.ofdm_symbol_size;
parent 348afdc1
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Showing with 35 additions and 56 deletions
openair1/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c
View file @ ef3be740
......@@ -140,7 +140,7 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
ul_ch,
8);
pil+=2;
re_offset = (re_offset+2)&(gNB->frame_parms.ofdm_symbol_size-1);
re_offset = (re_offset+2) % gNB->frame_parms.ofdm_symbol_size;
rxF = (int16_t *)&rxdataF[aarx][(symbol_offset+nushift+re_offset)];
//for (int i= 0; i<8; i++)
//printf("ul_ch addr %p %d\n", ul_ch+i, *(ul_ch+i));
......@@ -156,7 +156,7 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
ul_ch,
8);
pil+=2;
re_offset = (re_offset+2)&(gNB->frame_parms.ofdm_symbol_size-1);
re_offset = (re_offset+2) % gNB->frame_parms.ofdm_symbol_size;
rxF = (int16_t *)&rxdataF[aarx][(symbol_offset+nushift+re_offset)];
//printf("ul_ch addr %p\n",ul_ch);
......@@ -175,7 +175,7 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
//printf("ul_ch addr %p %d\n", ul_ch+i, *(ul_ch+i));
pil+=2;
re_offset = (re_offset+2)&(gNB->frame_parms.ofdm_symbol_size-1);
re_offset = (re_offset+2) % gNB->frame_parms.ofdm_symbol_size;
rxF = (int16_t *)&rxdataF[aarx][(symbol_offset+nushift+re_offset)];
ul_ch+=8;
......@@ -193,7 +193,7 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
8);
pil+=2;
re_offset = (re_offset+2)&(gNB->frame_parms.ofdm_symbol_size-1);
re_offset = (re_offset+2) % gNB->frame_parms.ofdm_symbol_size;
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);
......@@ -206,7 +206,7 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
ul_ch,
8);
pil+=2;
re_offset = (re_offset+2)&(gNB->frame_parms.ofdm_symbol_size-1);
re_offset = (re_offset+2) % gNB->frame_parms.ofdm_symbol_size;
rxF = (int16_t *)&rxdataF[aarx][(symbol_offset+nushift+re_offset)];
ul_ch+=8;
......@@ -227,7 +227,7 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
//printf("ul_ch addr %p %d\n", ul_ch+i, *(ul_ch+i));
pil+=2;
re_offset = (re_offset+2)&(gNB->frame_parms.ofdm_symbol_size-1);
re_offset = (re_offset+2) % gNB->frame_parms.ofdm_symbol_size;
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);
......@@ -242,7 +242,7 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
8);
pil+=2;
re_offset = (re_offset+2)&(gNB->frame_parms.ofdm_symbol_size-1);
re_offset = (re_offset+2) % gNB->frame_parms.ofdm_symbol_size;
rxF = (int16_t *)&rxdataF[aarx][(symbol_offset+nushift+re_offset)];
ul_ch+=8;
......@@ -267,7 +267,7 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
pil += (idxPil-2);
ul_ch += (idxDC-4);
ul_ch = memset(ul_ch, 0, sizeof(int16_t)*10);
re_offset = (re_offset+idxDC/2-2)&(gNB->frame_parms.ofdm_symbol_size-1);
re_offset = (re_offset+idxDC/2-2) % gNB->frame_parms.ofdm_symbol_size;
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);
......@@ -281,7 +281,7 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
8);
pil += 4;
re_offset = (re_offset+4)&(gNB->frame_parms.ofdm_symbol_size-1);
re_offset = (re_offset+4) % gNB->frame_parms.ofdm_symbol_size;
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);
......@@ -298,7 +298,7 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
8);
pil += 4;
re_offset = (re_offset+4)&(gNB->frame_parms.ofdm_symbol_size-1);
re_offset = (re_offset+4) % gNB->frame_parms.ofdm_symbol_size;
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);
......
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