Review Comments are updated

- updated return function value to -1
- removed static variable for dmrs symbol selection for channel
- Updated sin cos quadrant check conditions
- removed casting from PTRS slope and related calculations

openair1/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c

@@ -25,6 +25,7 @@
 #include "nr_ul_estimation.h"
 #include "PHY/sse_intrin.h"
 #include "PHY/NR_REFSIG/nr_refsig.h"
+#include "PHY/NR_REFSIG/dmrs_nr.h"
 #include "PHY/NR_REFSIG/ptrs_nr.h"
 #include "PHY/NR_TRANSPORT/nr_transport_proto.h"
 #include "PHY/NR_UE_ESTIMATION/filt16a_32.h"

openair1/PHY/NR_REFSIG/dmrs_nr.c

@@ -363,7 +363,7 @@ void generate_dmrs_pbch(uint32_t dmrs_pbch_bitmap[DMRS_PBCH_I_SSB][DMRS_PBCH_N_H
 #endif
 }
 /* return the position of next dmrs symbol in a slot */
-int get_next_dmrs_symbol_in_slot(uint16_t  ul_dmrs_symb_pos, uint8_t counter, uint8_t end_symbol)
+int8_t get_next_dmrs_symbol_in_slot(uint16_t  ul_dmrs_symb_pos, uint8_t counter, uint8_t end_symbol)
 {
   for(uint8_t symbol = counter; symbol < end_symbol; symbol++)
   {
@@ -372,7 +372,7 @@ int get_next_dmrs_symbol_in_slot(uint16_t  ul_dmrs_symb_pos, uint8_t counter, ui
       return symbol;
     }
   }
-  return 0;
+  return -1;
 }
 
 
@@ -386,3 +386,29 @@ uint8_t get_dmrs_symbols_in_slot(uint16_t l_prime_mask,  uint16_t nb_symb)
   }
   return tmp;
 }
+
+/* return the position of valid dmrs symbol in a slot for channel compensation */
+int8_t get_valid_dmrs_idx_for_channel_est(uint16_t  dmrs_symb_pos, uint8_t counter)
+{
+  int8_t  symbIdx = -1;
+  /* if current symbol is DMRS then return this index */
+  if(is_dmrs_symbol(counter,  dmrs_symb_pos ) ==1)
+  {
+    return counter;
+  }
+  /* find previous DMRS symbol */
+  for(int8_t symbol = counter;symbol >=0 ; symbol--)
+  {
+    if((1<<symbol & dmrs_symb_pos)> 0)
+    {
+      symbIdx = symbol;
+      break;
+    }
+  }
+  /* if there is no previous dmrs available then find the next possible*/
+  if(symbIdx == -1)
+  {
+    symbIdx = get_next_dmrs_symbol_in_slot(dmrs_symb_pos,counter,15);
+  }
+  return symbIdx;
+}

openair1/PHY/NR_REFSIG/dmrs_nr.h

@@ -61,6 +61,12 @@ uint8_t allowed_xlsch_re_in_dmrs_symbol(uint16_t k,
                                         uint8_t numDmrsCdmGrpsNoData,
                                         uint8_t dmrs_type);
 
+void nr_gen_ref_conj_symbols(uint32_t *in, uint32_t length, int16_t *output, uint16_t offset, int mod_order);
+int8_t get_next_dmrs_symbol_in_slot(uint16_t  ul_dmrs_symb_pos, uint8_t counter, uint8_t end_symbol);
+uint8_t get_dmrs_symbols_in_slot(uint16_t l_prime_mask,  uint16_t nb_symb);
+int8_t get_valid_dmrs_idx_for_channel_est(uint16_t  dmrs_symb_pos, uint8_t counter);
+
+static inline uint8_t is_dmrs_symbol(uint8_t l, uint16_t dmrsSymbMask ) { return ((dmrsSymbMask >> l) & 0x1); }
 #undef EXTERN
 
 #endif /* DMRS_NR_H */

openair1/PHY/NR_REFSIG/nr_refsig.h

@@ -52,13 +52,7 @@ int nr_pusch_dmrs_rx(PHY_VARS_gNB *gNB,
                      uint8_t dmrs_type);
 
 void init_scrambling_luts(void);
-void nr_gen_ref_conj_symbols(uint32_t *in, uint32_t length, int16_t *output, uint16_t offset, int mod_order);
-uint8_t get_next_dmrs_symbol_in_slot(uint16_t  ul_dmrs_symb_pos, uint8_t counter, uint8_t end_symbol);
-uint8_t get_dmrs_symbols_in_slot(uint16_t l_prime_mask,  uint16_t nb_symb);
-
-
 void nr_generate_modulation_table(void);
-static inline uint8_t is_dmrs_symbol(uint8_t l, uint16_t dmrsSymbMask ) { return ((dmrsSymbMask >> l) & 0x1); }
 
 extern __m64 byte2m64_re[256];
 extern __m64 byte2m64_im[256];

openair1/PHY/NR_REFSIG/ptrs_nr.c

@@ -192,29 +192,29 @@ uint8_t get_ptrs_symbols_in_slot(uint16_t l_prime_mask, uint16_t start_symb, uin
 }
 
 /* return the position of next ptrs symbol in a slot */
-uint8_t get_next_ptrs_symbol_in_slot(uint16_t  ptrs_symb_pos, uint8_t counter, uint8_t nb_symb)
+int8_t get_next_ptrs_symbol_in_slot(uint16_t  ptrs_symb_pos, uint8_t counter, uint8_t nb_symb)
 {
-  for(uint8_t symbol = counter; symbol < nb_symb; symbol++)
+  for(int8_t symbol = counter; symbol < nb_symb; symbol++)
     {
       if((ptrs_symb_pos >>symbol)&0x01 )
       {
         return symbol;
       }
     }
-  return 0;
+  return -1;
 }
 
 /* get the next nearest estimate from DMRS or PTRS */
-uint8_t get_next_estimate_in_slot(uint16_t  ptrsSymbPos,uint16_t  dmrsSymbPos, uint8_t counter,uint8_t nb_symb)
+int8_t get_next_estimate_in_slot(uint16_t  ptrsSymbPos,uint16_t  dmrsSymbPos, uint8_t counter,uint8_t nb_symb)
 {
-  uint8_t nextPtrs = get_next_ptrs_symbol_in_slot(ptrsSymbPos, counter,nb_symb);
-  uint8_t nextDmrs = get_next_dmrs_symbol_in_slot(dmrsSymbPos, counter,nb_symb);
-  if(nextDmrs == 0)
+  int8_t nextPtrs = get_next_ptrs_symbol_in_slot(ptrsSymbPos, counter,nb_symb);
+  int8_t nextDmrs = get_next_dmrs_symbol_in_slot(dmrsSymbPos, counter,nb_symb);
+  if(nextDmrs == -1)
   {
     return nextPtrs;
   }
   /* Special case when DMRS is next valid estimation */
-  if(nextPtrs == 0 && nextDmrs !=0)
+  if(nextPtrs == -1)
   {
     return nextDmrs;
   }
@@ -360,9 +360,9 @@ int8_t nr_ptrs_process_slot(uint16_t dmrsSymbPos,
   int32_t         slope      = 0;
   int16_t         *slope_p   = (int16_t*)&slope; 
   uint8_t         symbInSlot = startSymbIdx + noSymb;
-  uint8_t         rightRef   = 0;
-  uint8_t         leftRef    = 0;
-  uint8_t         tmp        = 0;
+  int8_t         rightRef   = 0;
+  int8_t         leftRef    = 0;
+  int8_t         tmp        = 0;
   for(uint8_t symb = startSymbIdx; symb <symbInSlot;  symb ++)
     {
       /* set DMRS estimates to 0 angle with magnitude 1 */
@@ -384,7 +384,7 @@ int8_t nr_ptrs_process_slot(uint16_t dmrsSymbPos,
         else
           {
             /* The very first symbol must be a PTRS or DMRS */
-            if((symb == startSymbIdx) && (leftRef == 0) && (rightRef == 0))
+            if((symb == startSymbIdx) && (leftRef == -1) && (rightRef == -1))
               {
                 printf("Wrong PTRS Setup, PTRS compensation will be skipped !");
                 return -1;
@@ -396,7 +396,7 @@ int8_t nr_ptrs_process_slot(uint16_t dmrsSymbPos,
                 /* calculate slope from next valid estimates*/
                 tmp =  get_next_estimate_in_slot(ptrsSymbPos,dmrsSymbPos,rightRef+1,symbInSlot);
                 /* Special case when DMRS is not followed by PTRS symbol then reuse old slope */
-                if(tmp!=0)
+                if(tmp!=-1)
                 {
                   get_slope_from_estimates(rightRef, tmp, estPerSymb, slope_p);
                 }
@@ -405,12 +405,12 @@ int8_t nr_ptrs_process_slot(uint16_t dmrsSymbPos,
               }
             else if(is_ptrs_symbol(rightRef,ptrsSymbPos))
               {
-                /* calculate slope from next valid estimates*/
+                /* calculate slope from next valid estimates */
                 get_slope_from_estimates(leftRef,rightRef,estPerSymb, slope_p);
                 ptrs_estimate_from_slope(estPerSymb,slope_p,leftRef, rightRef);
                 symb = rightRef -1;
               }
-            else if((rightRef ==0) && (symb <symbInSlot))
+            else if((rightRef ==-1) && (symb <symbInSlot))
               {
                 // in right extrapolation use the last slope
 #ifdef DEBUG_PTRS
@@ -433,8 +433,8 @@ int8_t nr_ptrs_process_slot(uint16_t dmrsSymbPos,
 void get_slope_from_estimates(uint8_t start, uint8_t end, int16_t *est_p, int16_t *slope_p)
 {
   uint8_t distance = end - start;
-  slope_p[0] = (((double)(est_p[end*2]) - (double)(est_p[start*2])) /(double)distance);
-  slope_p[1] = (((double)(est_p[(end*2)+1]) - (double)(est_p[(start*2)+1])) /(double)distance);
+  slope_p[0] = (est_p[end*2] - est_p[start*2]) /distance;
+  slope_p[1] = (est_p[(end*2)+1] - est_p[(start*2)+1]) /distance;
 #ifdef DEBUG_PTRS
   printf("[PHY][PTRS]: Slop is :(%4d %4d) between Symbol %2d & Symbol %2d\n", slope_p[0],slope_p[1], start, end);
   //printf("%d %d - %d %d\n",est_p[end*2],est_p[(end*2)+1],est_p[start*2],est_p[(start*2)+1]);
@@ -446,8 +446,8 @@ void ptrs_estimate_from_slope(int16_t *error_est, int16_t *slope_p, uint8_t star
 {
   for(uint8_t i = 1; i< (end -start);i++)
   {
-    error_est[(start+i)*2]      = 8 * (((double)(error_est[start*2]) * 0.125 ) + ((double)(0.125 * i * slope_p[0])));// real
-    error_est[((start +i)*2)+1] = 8 * (((double)(error_est[(start*2)+1]) * 0.125) + ((double)(0.125 * i * slope_p[1]))); //imag
+    error_est[(start+i)*2]      = (error_est[start*2]   + (i * slope_p[0]));// real
+    error_est[((start +i)*2)+1] = (error_est[(start*2)+1] + ( i * slope_p[1])); //imag
 #ifdef DEBUG_PTRS
   printf("[PHY][PTRS]: Estimated Symbol %2d -> %4d %4d from Slope (%4d %4d)\n", start+i,error_est[(start+i)*2],error_est[((start +i)*2)+1],
          slope_p[0],slope_p[1]);

openair1/PHY/NR_REFSIG/ptrs_nr.h

@@ -81,8 +81,8 @@ uint8_t is_ptrs_subcarrier(uint16_t k,
 static inline uint8_t is_ptrs_symbol(uint8_t l, uint16_t ptrs_symbols) { return ((ptrs_symbols >> l) & 1); }
 
 uint8_t get_ptrs_symbols_in_slot(uint16_t l_prime_mask, uint16_t start_symb, uint16_t nb_symb);
-uint8_t get_next_ptrs_symbol_in_slot(uint16_t  ptrsSymbPos, uint8_t counter, uint8_t nb_symb);
-uint8_t get_next_estimate_in_slot(uint16_t  ptrsSymbPos,uint16_t  dmrsSymbPos, uint8_t counter,uint8_t nb_symb);
+int8_t get_next_ptrs_symbol_in_slot(uint16_t  ptrsSymbPos, uint8_t counter, uint8_t nb_symb);
+int8_t get_next_estimate_in_slot(uint16_t  ptrsSymbPos,uint16_t  dmrsSymbPos, uint8_t counter,uint8_t nb_symb);
 void get_slope_from_estimates(uint8_t leftSide, uint8_t rightSide, int16_t *est_p, int16_t *slope_p);
 int8_t nr_ptrs_process_slot(uint16_t dmrsSymbPos,
                             uint16_t ptrsSymbPos,

openair1/PHY/NR_TRANSPORT/nr_dlsch.c

@@ -37,11 +37,10 @@
 #include "PHY/NR_REFSIG/dmrs_nr.h"
 #include "PHY/NR_REFSIG/ptrs_nr.h"
 #include "common/utils/LOG/vcd_signal_dumper.h"
+#include "LAYER2/NR_MAC_gNB/mac_proto.h"
 
 //#define DEBUG_DLSCH
 //#define DEBUG_DLSCH_MAPPING
-// forward declarations for mac function to avoid semantic issues
-extern int get_num_dmrs(uint16_t dmrs_mask );
 
 void nr_pdsch_codeword_scrambling(uint8_t *in,
                                   uint32_t size,

openair1/PHY/NR_UE_ESTIMATION/nr_dl_channel_estimation.c

@@ -25,6 +25,7 @@
 #include "nr_estimation.h"
 #include "PHY/NR_REFSIG/refsig_defs_ue.h"
 #include "PHY/NR_REFSIG/nr_refsig.h"
+#include "PHY/NR_REFSIG/dmrs_nr.h"
 #include "PHY/NR_REFSIG/ptrs_nr.h"
 #include "filt16a_32.h"
 

openair1/PHY/NR_UE_TRANSPORT/nr_dlsch_demodulation.c

@@ -40,6 +40,7 @@
 #include "openair1/PHY/NR_UE_ESTIMATION/nr_estimation.h"
 #include "openair1/PHY/NR_TRANSPORT/nr_dlsch.h"
 #include "PHY/NR_REFSIG/nr_refsig.h"
+#include "PHY/NR_REFSIG/dmrs_nr.h"
 
 #ifndef USER_MODE
 #define NOCYGWIN_STATIC static
@@ -2099,8 +2100,7 @@ unsigned short nr_dlsch_extract_rbs_single(int **rxdataF,
   unsigned char i,aarx; //,nsymb,sss_symb,pss_symb=0,l;
   int *dl_ch0,*dl_ch0_ext,*rxF,*rxF_ext;
 
-  int8_t DMRSdist = 15; //temporarily save the distance to the DMRS symbol 
-  static uint8_t validDmrsEst = 0; //store last DMRS Symbol index
+  int8_t validDmrsEst = 0; //store last DMRS Symbol index
 
   unsigned char j=0;
 
@@ -2111,15 +2111,9 @@ unsigned short nr_dlsch_extract_rbs_single(int **rxdataF,
 
     k = frame_parms->first_carrier_offset + NR_NB_SC_PER_RB*start_rb;
 
-    if(validDmrsEst == 0)
-    {
-      validDmrsEst = get_next_dmrs_symbol_in_slot(dlDmrsSymbPos, symbol, DMRSdist);
-    }
-    if(is_dmrs_symbol(symbol,dlDmrsSymbPos ) == 1)
-    {
-      validDmrsEst = symbol;
-    }
-    dl_ch0     = &dl_ch_estimates[aarx][(validDmrsEst*(frame_parms->ofdm_symbol_size))]; //use closest DMRS
+    validDmrsEst = get_valid_dmrs_idx_for_channel_est(dlDmrsSymbPos,symbol);
+
+    dl_ch0     = &dl_ch_estimates[aarx][(validDmrsEst*(frame_parms->ofdm_symbol_size))];
 
     dl_ch0_ext = &dl_ch_estimates_ext[aarx][symbol*(nb_rb_pdsch*12)];
 

openair1/PHY/defs_nr_UE.h

@@ -906,7 +906,7 @@ typedef struct {
   uint32_t nr_gold_pbch[2][64][NR_PBCH_DMRS_LENGTH_DWORD];
 
   /// PDSCH DMRS
-  uint32_t nr_gold_pdsch[2][20][14][NR_MAX_PDSCH_DMRS_INIT_LENGTH_DWORD];//sfn
+  uint32_t nr_gold_pdsch[2][20][14][NR_MAX_PDSCH_DMRS_INIT_LENGTH_DWORD];
 
   /// PDCCH DMRS
   uint32_t nr_gold_pdcch[7][20][3][52];

openair1/SIMULATION/TOOLS/phase_noise.c

@@ -37,23 +37,34 @@ void phase_noise(double ts, int16_t * InRe, int16_t * InIm)
   int16_t IdxModulo = ((int32_t)(IdxDouble>0 ? IdxDouble+0.5 : IdxDouble-0.5)) % (ResolSinCos*4);
   IdxModulo = IdxModulo<0 ? IdxModulo+ResolSinCos*4 : IdxModulo;
 
-  if ( IdxModulo>=0 && IdxModulo<ResolSinCos ) {
+  if(IdxModulo<2*ResolSinCos)//< 2 check for 1st and 2nd
+  {
+    if(IdxModulo>=ResolSinCos)//>= 1 is 2nd Quadrant
+    {
+      SinValue = LUTSin[2*ResolSinCos-IdxModulo];
+      CosValue = -LUTSin[IdxModulo-ResolSinCos];
+    }
+    else// 1st Quadrant
+    {
       SinValue = LUTSin[IdxModulo];
       CosValue = LUTSin[ResolSinCos-IdxModulo];
     }
-  else if ( IdxModulo>=ResolSinCos && IdxModulo<2*ResolSinCos ) {
-    SinValue = LUTSin[2*ResolSinCos-IdxModulo];
-    CosValue = -LUTSin[IdxModulo-ResolSinCos];
   }
-  else if ( IdxModulo>=2*ResolSinCos && IdxModulo<3*ResolSinCos ) {
+  else if((IdxModulo>2*ResolSinCos))//> 2 check for 3rd and 4th
+  {
+    if(IdxModulo>=3*ResolSinCos)//> 3 is 4th Quadrant
+    {
+      SinValue = -LUTSin[4*ResolSinCos-IdxModulo];
+      CosValue = LUTSin[IdxModulo-3*ResolSinCos];
+    }
+    else//3rd Quadrant
+    {
       SinValue = -LUTSin[IdxModulo-2*ResolSinCos];
       CosValue = -LUTSin[3*ResolSinCos-IdxModulo];
     }
-  else if ( IdxModulo>=3*ResolSinCos && IdxModulo<4*ResolSinCos ) {
-    SinValue = -LUTSin[4*ResolSinCos-IdxModulo];
-    CosValue = LUTSin[IdxModulo-3*ResolSinCos];
   }
-  else {
+  else
+  {
     AssertFatal(0==1,"Error in look-up table of sine function!\n");
   }
   x = ( ((int32_t)InRe[0] * CosValue) - ((int32_t)InIm[0] * SinValue ));
@@ -68,3 +79,4 @@ void InitSinLUT( void ) {
     LUTSin[i] = sin((double)(M_PI*i)/(2*ResolSinCos)) * (1<<14); //Format: Q14
   }
 }
+

openair2/LAYER2/NR_MAC_COMMON/nr_mac_common.c

@@ -1824,7 +1824,7 @@ void nr_get_tbs_dl(nfapi_nr_dl_tti_pdsch_pdu *pdsch_pdu,
                        R,
                        pdsch_rel15->rbSize,
                        N_sh_symb,
-                       N_PRB_DMRS*dmrs_length, // FIXME // This should be multiplied by the number of dmrs symbols
+                       N_PRB_DMRS*dmrs_length,
                        N_PRB_oh,
                        tb_scaling,
 		       pdsch_rel15->nrOfLayers)>>3;