Fix calculation of pucch interference power.

(cherry picked from commit 0622f7d40523e39334708ce4b9b0ee68e8fb2bf1)

openair1/PHY/LTE_TRANSPORT/pucch.c

@@ -721,6 +721,140 @@ int16_t pucchfmt3_Decode( int16_t b[48],
   }
 }
 
+
+uint32_t calc_pucch_1x_interference(PHY_VARS_eNB *eNB,
+		  int     frame,
+		  uint8_t subframe,
+		  uint8_t shortened_format
+)
+//-----------------------------------------------------------------------------
+{
+  LTE_eNB_COMMON *common_vars = &eNB->common_vars;
+  LTE_DL_FRAME_PARMS *frame_parms = &eNB->frame_parms;
+
+  uint32_t u,v,n,aa;
+  uint32_t z[12*14];
+  int16_t *zptr;
+  int16_t rxcomp[NB_ANTENNAS_RX][2*12*14];
+  uint8_t ns,N_UL_symb,nsymb;
+  uint8_t c = (frame_parms->Ncp==0) ? 3 : 2;
+  uint16_t i,j,re_offset;
+  uint8_t m,l;
+  uint8_t n_cs,alpha_ind;
+  int16_t tmp_re,tmp_im,W_re=0,W_im=0;
+  int16_t W4_nouse[4]={1,1,-1,-1};
+  int32_t interference_power;
+  int16_t *rxptr;
+  uint32_t symbol_offset;
+
+  uint8_t deltaPUCCH_Shift          = frame_parms->pucch_config_common.deltaPUCCH_Shift;
+  uint8_t Ncs1_div_deltaPUCCH_Shift = frame_parms->pucch_config_common.nCS_AN;
+
+  uint32_t u0 = (frame_parms->Nid_cell + frame_parms->pusch_config_common.ul_ReferenceSignalsPUSCH.grouphop[subframe<<1]) % 30;
+  uint32_t u1 = (frame_parms->Nid_cell + frame_parms->pusch_config_common.ul_ReferenceSignalsPUSCH.grouphop[1+(subframe<<1)]) % 30;
+  uint32_t v0=frame_parms->pusch_config_common.ul_ReferenceSignalsPUSCH.seqhop[subframe<<1];
+  uint32_t v1=frame_parms->pusch_config_common.ul_ReferenceSignalsPUSCH.seqhop[1+(subframe<<1)];
+  int calc_cnt;
+
+  if ((deltaPUCCH_Shift==0) || (deltaPUCCH_Shift>3)) {
+    LOG_E(PHY,"[eNB] rx_pucch: Illegal deltaPUCCH_shift %d (should be 1,2,3)\n",deltaPUCCH_Shift);
+    return(-1);
+  }
+
+  if (Ncs1_div_deltaPUCCH_Shift > 7) {
+    LOG_E(PHY,"[eNB] rx_pucch: Illegal Ncs1_div_deltaPUCCH_Shift %d (should be 0...7)\n",Ncs1_div_deltaPUCCH_Shift);
+    return(-1);
+  }
+
+  zptr = (int16_t *)z;
+  N_UL_symb = (frame_parms->Ncp==NORMAL) ? 7 : 6;
+
+  interference_power=0;
+  calc_cnt=0;
+  // loop over 2 slots
+  for (n_cs=0; n_cs<12; n_cs++) {
+    for (ns=(subframe<<1),u=u0,v=v0; ns<(2+(subframe<<1)); ns++,u=u1,v=v1) {
+
+      //loop over symbols in slot
+      for (l=0; l<N_UL_symb; l++) {
+        if(((l>1)&&(l<N_UL_symb-2)) || ((ns==(1+(subframe<<1))) && (shortened_format==1)) ){
+          continue;
+        }
+
+        if (l<2) {                                         // data
+          W_re=W4_nouse[l];
+          W_im=0;
+        } else if ((l>=N_UL_symb-2)) {                     // data
+          W_re=W4_nouse[l-N_UL_symb+4];
+          W_im=0;
+        }
+
+        alpha_ind=0;
+        // compute output sequence
+
+        for (n=0; n<12; n++) {
+
+          // this is r_uv^alpha(n)
+          tmp_re = (int16_t)(((int32_t)alpha_re[alpha_ind] * ul_ref_sigs[u][v][0][n<<1] - (int32_t)alpha_im[alpha_ind] * ul_ref_sigs[u][v][0][1+(n<<1)])>>15);
+          tmp_im = (int16_t)(((int32_t)alpha_re[alpha_ind] * ul_ref_sigs[u][v][0][1+(n<<1)] + (int32_t)alpha_im[alpha_ind] * ul_ref_sigs[u][v][0][n<<1])>>15);
+
+          // this is S(ns)*w_noc(m)*r_uv^alpha(n)
+          zptr[n<<1] = (tmp_re*W_re - tmp_im*W_im)>>15;
+          zptr[1+(n<<1)] = -(tmp_re*W_im + tmp_im*W_re)>>15;
+
+          alpha_ind = (alpha_ind + n_cs)%12;
+        } // n
+
+        zptr+=24;
+      } // l
+    } // ns
+
+    m = 0;
+
+    nsymb = N_UL_symb<<1;
+
+    zptr = (int16_t*)z;
+
+    // Do detection
+    for (aa=0; aa<frame_parms->nb_antennas_rx; aa++) {
+      for (j=0,l=0; l<nsymb; l++) {
+        if((((l%N_UL_symb)>1)&&((l%N_UL_symb)<N_UL_symb-2)) || ((nsymb>=N_UL_symb) && (shortened_format==1)) ){
+          continue;
+        }
+          if ((l<(nsymb>>1)) && ((m&1) == 0))
+            re_offset = (m*6) + frame_parms->first_carrier_offset;
+          else if ((l<(nsymb>>1)) && ((m&1) == 1))
+            re_offset = frame_parms->first_carrier_offset + (frame_parms->N_RB_DL - (m>>1) - 1)*12;
+          else if ((m&1) == 0)
+            re_offset = frame_parms->first_carrier_offset + (frame_parms->N_RB_DL - (m>>1) - 1)*12;
+          else
+            re_offset = ((m-1)*6) + frame_parms->first_carrier_offset;
+
+        if (re_offset > frame_parms->ofdm_symbol_size)
+          re_offset -= (frame_parms->ofdm_symbol_size);
+
+        symbol_offset = (unsigned int)frame_parms->ofdm_symbol_size*l;
+        rxptr = (int16_t *)&common_vars->rxdataF[aa][symbol_offset];
+
+        for (i=0; i<12; i++,j+=2,re_offset++) {
+          if (re_offset==frame_parms->ofdm_symbol_size)
+            re_offset = 0;
+
+          rxcomp[aa][j]   = (int16_t)((rxptr[re_offset<<1]*(int32_t)zptr[j])>>15)   - ((rxptr[1+(re_offset<<1)]*(int32_t)zptr[1+j])>>15);
+          rxcomp[aa][1+j] = (int16_t)((rxptr[re_offset<<1]*(int32_t)zptr[1+j])>>15) + ((rxptr[1+(re_offset<<1)]*(int32_t)zptr[j])>>15);
+          interference_power+= ((int32_t)rxcomp[aa][j]*(int32_t)rxcomp[aa][j]+(int32_t)rxcomp[aa][1+j]*(int32_t)rxcomp[aa][1+j]);
+          calc_cnt++;
+        } //re
+      } // symbol
+    }  // antenna
+  }
+  calc_cnt/=12;
+  //printf("pucch noise %d %d %d\n",interference_power,calc_cnt,eNB->measurements.n0_subband_power_tot_dB[0]);
+  eNB->measurements.n0_pucch_dB = dB_fixed_x10(interference_power/calc_cnt)/10;
+  return 0;
+}
+
+
 /* PUCCH format3 << */
 
 uint32_t rx_pucch(PHY_VARS_eNB *eNB,
@@ -740,7 +874,8 @@ uint32_t rx_pucch(PHY_VARS_eNB *eNB,
   static int first_call = 1;
   LTE_eNB_COMMON *common_vars = &eNB->common_vars;
   LTE_DL_FRAME_PARMS *frame_parms = &eNB->frame_parms;
-  int8_t sigma2_dB = max(eNB->measurements.n0_subband_power_tot_dB[0], eNB->measurements.n0_subband_power_tot_dB[eNB->frame_parms.N_RB_UL-1]);
+  int8_t sigma2_dB = eNB->measurements.n0_pucch_dB;
+
   uint32_t u,v,n,aa;
   uint32_t z[12*14];
   int16_t *zptr;

openair1/PHY/LTE_TRANSPORT/transport_proto.h

@@ -621,7 +621,11 @@ void dlsch_scrambling(LTE_DL_FRAME_PARMS *frame_parms,
                       uint16_t frame,
                       uint8_t Ns);
 
-
+uint32_t calc_pucch_1x_interference(PHY_VARS_eNB *eNB,
+                 int     frame,
+                 uint8_t subframe,
+                 uint8_t shortened_format
+);
 
 uint32_t rx_pucch(PHY_VARS_eNB *phy_vars_eNB,
                   PUCCH_FMT_t fmt,

openair1/PHY/defs_eNB.h

@@ -419,6 +419,8 @@ typedef struct {
   int            subband_cqi_tot_dB[NUMBER_OF_UE_MAX][100];
   /// PRACH background noise level
   int            prach_I0;
+  /// PUCCH background noise level
+  int            n0_pucch_dB;
 } PHY_MEASUREMENTS_eNB;
 
 

openair1/SCHED/phy_procedures_lte_eNb.c

@@ -791,6 +791,8 @@ uci_procedures(PHY_VARS_eNB *eNB,
   LTE_eNB_UCI *uci = NULL;
   LTE_DL_FRAME_PARMS *fp = &(eNB->frame_parms);
 
+  calc_pucch_1x_interference(eNB, frame, subframe, 0);
+  
   for (int i = 0; i < NUMBER_OF_UCI_VARS_MAX; i++) {
     uci = &(eNB->uci_vars[i]);