Common Phase error estimation and compensation in uplink.

FEATURE STATEMENT:
- Introduce linear phase error noise model in Uplink at UE
- Perform common phase error (CPE) estimation and compensation at gNB

SOLUTION:
- A linear phase shift model is introduced in simulation.
- PTRS symbols are used to perform estimation of CPE from DMRS compensated signal
- The estimated values are interpolated in time domain and signal is compensated for the CPE.
- PTRS processing is done in Frequency Domain for each symbol in a slot and
  LLR's are calculated for each symbol accordingly.

IMPLEMENTATION:
* sim.h/channle_sim.c
- Linear Phase Noise Generation model definition.
* nr_ul_channel_estimation.c/nr_ul_estimation.h
- CPE estimation from PTRS and DMRS compensated signal.
* nr_dmrs_rx.c/nr_refsig.h
- Regenerate PTRS symbols at gNB.
* nr_ulsch_demodulation.c
- Removed old PTRS processing code and move to a common PTRS processing function
* defs_gNB.h/init.c
- New PTRS variables definition and initialization
* nr_ulsch_ue.c
- Corrected PTRS parameter to get new PTRS symbols for each OFDM symbol

TESTING
* ulsim.c
- Added Phase noise, Enable PTRS signal and verified the output.

VERIFICATION
- The LLR are rotated back with estimated CPE and no error is observed in scrambling/decoding

cmake_targets/CMakeLists.txt

@@ -2303,6 +2303,7 @@ add_library(LFDS7
 add_library(SIMU_COMMON
   ${OPENAIR1_DIR}/SIMULATION/TOOLS/random_channel.c
   ${OPENAIR1_DIR}/SIMULATION/TOOLS/rangen_double.c
+  ${OPENAIR1_DIR}/SIMULATION/TOOLS/phase_noise.c
   )
 
 # Simulation library

cmake_targets/build_oai

@@ -209,7 +209,7 @@ function main() {
                     GDB=0
                     CMAKE_BUILD_TYPE="RelWithDebInfo"
                     echo_info "Will Compile with gdb symbols"
-                    CMAKE_CMD="$CMAKE_CMD -DCMAKE_BUILD_TYPE=RelWithDebInfo"
+                    CMAKE_CMD="$CMAKE_CMD -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_EXPORT_COMPILE_COMMANDS=1"
                     shift
                     ;;
                 "MinSizeRel")

openair1/PHY/INIT/nr_init.c

@@ -247,10 +247,13 @@ int phy_init_nr_gNB(PHY_VARS_gNB *gNB,
     pusch_vars[ULSCH_id]->ul_ch_estimates_ext   = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
     pusch_vars[ULSCH_id]->ul_ch_ptrs_estimates     = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
     pusch_vars[ULSCH_id]->ul_ch_ptrs_estimates_ext = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
+    pusch_vars[ULSCH_id]->ptrs_phase_per_slot   = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
+    pusch_vars[ULSCH_id]->ptrs_valid_re_per_slot= (int16_t **)malloc16(Prx*sizeof(int16_t *) );
     pusch_vars[ULSCH_id]->ul_ch_estimates_time  = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
     pusch_vars[ULSCH_id]->rxdataF_comp          = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
-    pusch_vars[ULSCH_id]->ul_ch_mag0             = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
-    pusch_vars[ULSCH_id]->ul_ch_magb0            = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
+    pusch_vars[ULSCH_id]->rxdataF_ptrs_comp     = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
+    pusch_vars[ULSCH_id]->ul_ch_mag0            = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
+    pusch_vars[ULSCH_id]->ul_ch_magb0           = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
     pusch_vars[ULSCH_id]->ul_ch_mag             = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
     pusch_vars[ULSCH_id]->ul_ch_magb            = (int32_t **)malloc16(Prx*sizeof(int32_t *) );
     pusch_vars[ULSCH_id]->rho                   = (int32_t **)malloc16_clear(Prx*sizeof(int32_t*) );
@@ -264,9 +267,12 @@ int phy_init_nr_gNB(PHY_VARS_gNB *gNB,
       pusch_vars[ULSCH_id]->ul_ch_estimates_time[i]  = (int32_t *)malloc16_clear( 2*sizeof(int32_t)*fp->ofdm_symbol_size );
       pusch_vars[ULSCH_id]->ul_ch_ptrs_estimates[i]       = (int32_t *)malloc16_clear( sizeof(int32_t)*fp->ofdm_symbol_size*2*fp->symbols_per_slot ); // max intensity in freq is 1 sc every 2 RBs
       pusch_vars[ULSCH_id]->ul_ch_ptrs_estimates_ext[i]   = (int32_t *)malloc16_clear( sizeof(int32_t)*fp->ofdm_symbol_size*2*fp->symbols_per_slot );
+      pusch_vars[ULSCH_id]->ptrs_phase_per_slot[i]   = (int32_t *)malloc16_clear( sizeof(int32_t)*fp->symbols_per_slot); // symbols per slot
+      pusch_vars[ULSCH_id]->ptrs_valid_re_per_slot[i]= (int16_t *)malloc16_clear( sizeof(int16_t)*fp->symbols_per_slot);
       pusch_vars[ULSCH_id]->rxdataF_comp[i]          = (int32_t *)malloc16_clear( sizeof(int32_t)*N_RB_UL*12*fp->symbols_per_slot );
-      pusch_vars[ULSCH_id]->ul_ch_mag0[i]             = (int32_t *)malloc16_clear( fp->symbols_per_slot*sizeof(int32_t)*N_RB_UL*12 );
-      pusch_vars[ULSCH_id]->ul_ch_magb0[i]            = (int32_t *)malloc16_clear( fp->symbols_per_slot*sizeof(int32_t)*N_RB_UL*12 );
+      pusch_vars[ULSCH_id]->rxdataF_ptrs_comp[i]     = (int32_t *)malloc16_clear( sizeof(int32_t)*N_RB_UL*12*fp->symbols_per_slot );
+      pusch_vars[ULSCH_id]->ul_ch_mag0[i]            = (int32_t *)malloc16_clear( fp->symbols_per_slot*sizeof(int32_t)*N_RB_UL*12 );
+      pusch_vars[ULSCH_id]->ul_ch_magb0[i]           = (int32_t *)malloc16_clear( fp->symbols_per_slot*sizeof(int32_t)*N_RB_UL*12 );
       pusch_vars[ULSCH_id]->ul_ch_mag[i]             = (int32_t *)malloc16_clear( fp->symbols_per_slot*sizeof(int32_t)*N_RB_UL*12 );
       pusch_vars[ULSCH_id]->ul_ch_magb[i]            = (int32_t *)malloc16_clear( fp->symbols_per_slot*sizeof(int32_t)*N_RB_UL*12 );
       pusch_vars[ULSCH_id]->rho[i]                   = (int32_t *)malloc16_clear( sizeof(int32_t)*(fp->N_RB_UL*12*7*2) );
@@ -334,7 +340,10 @@ void phy_free_nr_gNB(PHY_VARS_gNB *gNB)
       free_and_zero(pusch_vars[ULSCH_id]->ul_ch_estimates_time[i]);
       free_and_zero(pusch_vars[ULSCH_id]->ul_ch_ptrs_estimates[i]);
       free_and_zero(pusch_vars[ULSCH_id]->ul_ch_ptrs_estimates_ext[i]);
+      free_and_zero(pusch_vars[ULSCH_id]->ptrs_phase_per_slot[i]);
+      free_and_zero(pusch_vars[ULSCH_id]->ptrs_valid_re_per_slot[i]);
       free_and_zero(pusch_vars[ULSCH_id]->rxdataF_comp[i]);
+      free_and_zero(pusch_vars[ULSCH_id]->rxdataF_ptrs_comp[i]);
       free_and_zero(pusch_vars[ULSCH_id]->ul_ch_mag0[i]);
       free_and_zero(pusch_vars[ULSCH_id]->ul_ch_magb0[i]);
       free_and_zero(pusch_vars[ULSCH_id]->ul_ch_mag[i]);
@@ -349,7 +358,10 @@ void phy_free_nr_gNB(PHY_VARS_gNB *gNB)
     free_and_zero(pusch_vars[ULSCH_id]->ul_ch_ptrs_estimates);
     free_and_zero(pusch_vars[ULSCH_id]->ul_ch_ptrs_estimates_ext);
     free_and_zero(pusch_vars[ULSCH_id]->ul_ch_estimates_time);
+    free_and_zero(pusch_vars[ULSCH_id]->ptrs_phase_per_slot);
+    free_and_zero(pusch_vars[ULSCH_id]->ptrs_valid_re_per_slot);
     free_and_zero(pusch_vars[ULSCH_id]->rxdataF_comp);
+    free_and_zero(pusch_vars[ULSCH_id]->rxdataF_ptrs_comp);
     free_and_zero(pusch_vars[ULSCH_id]->ul_ch_mag0);
     free_and_zero(pusch_vars[ULSCH_id]->ul_ch_magb0);
     free_and_zero(pusch_vars[ULSCH_id]->ul_ch_mag);

openair1/PHY/NR_ESTIMATION/nr_ul_estimation.h

@@ -48,4 +48,30 @@ int nr_pusch_channel_estimation(PHY_VARS_gNB *gNB,
 
 int nr_est_timing_advance_pusch(PHY_VARS_gNB* phy_vars_gNB, int UE_id);
 
+
+void nr_pusch_ptrs_processing(PHY_VARS_gNB *gNB,
+                              nfapi_nr_pusch_pdu_t *rel15_ul,
+                              uint8_t ulsch_id,
+                              uint8_t nr_tti_rx,
+                              uint8_t dmrs_symbol_flag,
+                              unsigned char symbol,
+                              uint32_t nb_re_pusch);
+
+void nr_pusch_phase_estimation(NR_DL_FRAME_PARMS *frame_parms,
+                               nfapi_nr_pusch_pdu_t *rel15_ul,
+                               int16_t *ptrs_ch_p,
+                               unsigned char Ns,
+                               unsigned char symbol,
+                               int16_t *rxF_comp,
+                               uint32_t ***ptrs_gold_seq,
+                               int16_t *error_est,
+                               uint16_t  *ptrs_sc);
+
+void nr_pusch_phase_interpolation(int16_t *error_est,
+                                  uint8_t start_symbol,
+                                  uint8_t end_symbol);
+
+int nr_ptrs_find_next_estimate(int16_t *error_est,
+                               uint8_t counter,
+                               uint8_t end_symbol);
 #endif

openair1/PHY/NR_REFSIG/dmrs_nr.c

@@ -362,4 +362,25 @@ void generate_dmrs_pbch(uint32_t dmrs_pbch_bitmap[DMRS_PBCH_I_SSB][DMRS_PBCH_N_H
   free(dmrs_sequence);
 #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)
+{
+  for(uint8_t symbol = counter; symbol < end_symbol; symbol++)
+    if((ul_dmrs_symb_pos >>symbol)&0x01 )
+    {
+      return symbol;
+    }
+  return 0;
+}
+
 
+/* return the total number of dmrs symbol in a slot */
+uint8_t get_dmrs_symbols_in_slot(uint16_t l_prime_mask,  uint16_t nb_symb)
+{
+  uint8_t tmp = 0;
+  for (int i = 0; i < nb_symb; i++)
+  {
+    tmp += (l_prime_mask >> i) & 0x01;
+  }
+  return tmp;
+}

openair1/PHY/NR_REFSIG/nr_dmrs_rx.c

@@ -223,3 +223,30 @@ int nr_pbch_dmrs_rx(int symbol,
   
   return(0);
 }
+
+/*!
+  \brief This function generate gold ptrs sequence for each OFDM symbol
+  \param *in gold sequence for ptrs per OFDM symbol
+  \param length is number of RE in a OFDM symbol
+  \param *output pointer to all ptrs RE in a OFDM symbol
+*/
+void nr_ptrs_rx_gen(uint32_t *in, uint32_t length, int16_t *output)
+{
+  uint16_t offset;
+  uint8_t idx, b_idx;
+  int mod_order = 2;
+  offset = NR_MOD_TABLE_QPSK_OFFSET;
+  for (int i=0; i<length/mod_order; i++)
+    {
+      idx = 0;
+      for (int j=0; j<mod_order; j++)
+        {
+          b_idx = (i*mod_order+j)&0x1f;
+          if (i && (!b_idx))
+            in++;
+          idx ^= (((*in)>>b_idx)&1)<<(mod_order-j-1);
+        }
+      output[i<<1] = nr_rx_mod_table[(offset+idx)<<1];
+      output[(i<<1)+1] =  nr_rx_mod_table[((offset+idx)<<1)+1];
+    }
+}

openair1/PHY/NR_REFSIG/nr_refsig.h

@@ -52,6 +52,9 @@ int nr_pusch_dmrs_rx(PHY_VARS_gNB *gNB,
                      uint8_t dmrs_type);
 
 void init_scrambling_luts(void);
+void nr_ptrs_rx_gen(uint32_t *in, uint32_t length, int16_t *output);
+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);
 
 extern __m64 byte2m64_re[256];
 extern __m64 byte2m64_im[256];

openair1/PHY/NR_UE_TRANSPORT/nr_ulsch_ue.c

@@ -372,7 +372,7 @@ void nr_ue_ulsch_procedures(PHY_VARS_NR_UE *UE,
     uint16_t m=0, n=0, dmrs_idx=0, ptrs_idx = 0;
 
     for (l=start_symbol; l<start_symbol+number_of_symbols; l++) {
-
+      ptrs_idx = 0; // every PTRS symbol has a new gold sequence
       k = start_sc;
       n = 0;
       dmrs_idx = 0;

openair1/PHY/defs_gNB.h

@@ -403,6 +403,10 @@ typedef struct {
   /// - first index: rx antenna id [0..nb_antennas_rx[
   /// - second index: ? [0..12*N_RB_UL*frame_parms->symbols_per_tti[
   int32_t **rxdataF_comp;
+  /// \brief Holds the PTRS compensated signal.
+  /// - first index: rx antenna id [0..nb_antennas_rx[
+  /// - second index: ? [0..12*N_RB_UL*frame_parms->symbols_per_tti[
+  int32_t **rxdataF_ptrs_comp;
   /// \brief Magnitude of the UL channel estimates. Used for 2nd-bit level thresholds in LLR computation
   /// - first index: rx antenna id [0..nb_antennas_rx[
   /// - second index: ? [0..12*N_RB_UL*frame_parms->symbols_per_tti[
@@ -446,6 +450,14 @@ typedef struct {
   uint16_t ptrs_symbols;
   // PTRS subcarriers per OFDM symbol
   uint16_t ptrs_sc_per_ofdm_symbol;
+  /// \brief Estimated phase error based upon PTRS on each symbol .
+  /// - first index: ? [0..7] Number of Antenna
+  /// - second index: ? [0...14] smybol per slot
+  int32_t **ptrs_phase_per_slot;
+  /// \brief Total RE count after PTRS RE's are extracted from respective symbol.
+  /// - first index: ? [0..7] Number of Antenna
+  /// - second index: ? [0...14] smybol per slot
+  int16_t **ptrs_valid_re_per_slot;
   /// flag to verify if channel level computation is done
   uint8_t cl_done;
 } NR_gNB_PUSCH;
@@ -775,9 +787,11 @@ typedef struct PHY_VARS_gNB_s {
   time_stats_t ulsch_deinterleaving_stats;
   time_stats_t ulsch_unscrambling_stats;
   time_stats_t ulsch_channel_estimation_stats;
+  time_stats_t ulsch_ptrs_processing_stats;
   time_stats_t ulsch_channel_compensation_stats;
   time_stats_t ulsch_rbs_extraction_stats;
   time_stats_t ulsch_llr_stats;
+
   /*
   time_stats_t rx_dft_stats;
   time_stats_t ulsch_freq_offset_estimation_stats;

openair1/SIMULATION/NR_PHY/ulsim.c

@@ -447,7 +447,7 @@ int main(int argc, char **argv)
 				  0);
   fix_scc(scc,ssb_bitmap);
 
-  xer_fprint(stdout, &asn_DEF_NR_CellGroupConfig, (const void*)secondaryCellGroup);
+  // xer_fprint(stdout, &asn_DEF_NR_CellGroupConfig, (const void*)secondaryCellGroup);
 
   AssertFatal((gNB->if_inst         = NR_IF_Module_init(0))!=NULL,"Cannot register interface");
 
@@ -562,14 +562,13 @@ int main(int argc, char **argv)
   uint8_t ptrs_time_density = get_L_ptrs(ptrs_mcs1, ptrs_mcs2, ptrs_mcs3, Imcs, mcs_table);
   uint8_t ptrs_freq_density = get_K_ptrs(n_rb0, n_rb1, nb_rb);
   int ptrs_symbols = 0; // to calculate total PTRS RE's in a slot
+  double ts = 1.0/(frame_parms->subcarrier_spacing * frame_parms->ofdm_symbol_size);
+
+  number_dmrs_symbols = get_dmrs_symbols_in_slot(l_prime_mask, nb_symb_sch);
 
   if(1<<ptrs_time_density >= nb_symb_sch)
     pdu_bit_map &= ~PUSCH_PDU_BITMAP_PUSCH_PTRS; // disable PUSCH PTRS
 
-  for (i = 0; i < nb_symb_sch; i++) {
-    number_dmrs_symbols += (l_prime_mask >> i) & 0x01;
-  }
-
   mod_order      = nr_get_Qm_ul(Imcs, 0);
   code_rate      = nr_get_code_rate_ul(Imcs, 0);
 
@@ -586,6 +585,7 @@ int main(int argc, char **argv)
       reset_meas(&gNB->ulsch_ldpc_decoding_stats);
       reset_meas(&gNB->ulsch_unscrambling_stats);
       reset_meas(&gNB->ulsch_channel_estimation_stats);
+      reset_meas(&gNB->ulsch_ptrs_processing_stats);
       reset_meas(&gNB->ulsch_llr_stats);
       reset_meas(&gNB->ulsch_channel_compensation_stats);
       reset_meas(&gNB->ulsch_rbs_extraction_stats);
@@ -765,19 +765,24 @@ int main(int argc, char **argv)
 
       int error_flag;
       for (trial = 0; trial < n_trials; trial++) {
-	
-	error_flag = 0;
-	  //----------------------------------------------------------
-	  //------------------------ add noise -----------------------
-	  //----------------------------------------------------------
-	if (input_fd == NULL ) {
-	  for (i=0; i<slot_length; i++) {
-	    for (ap=0; ap<frame_parms->nb_antennas_rx; ap++) {
-	      ((int16_t*) &gNB->common_vars.rxdata[ap][slot_offset])[(2*i) + (delay*2)]   = (int16_t)((double)(((int16_t *)&UE->common_vars.txdata[ap][slot_offset])[(i<<1)])/sqrt(scale)   + (sqrt(sigma/2)*gaussdouble(0.0,1.0))); // convert to fixed point
-	      ((int16_t*) &gNB->common_vars.rxdata[ap][slot_offset])[(2*i)+1 + (delay*2)]   = (int16_t)((double)(((int16_t *)&UE->common_vars.txdata[ap][slot_offset])[(i<<1)+1])/sqrt(scale) + (sqrt(sigma/2)*gaussdouble(0.0,1.0)));
-	    }
-	  }
-	}
+
+        error_flag = 0;
+        //----------------------------------------------------------
+        //------------------------ add noise -----------------------
+        //----------------------------------------------------------
+        if (input_fd == NULL ) {
+          for (i=0; i<slot_length; i++) {
+            for (ap=0; ap<frame_parms->nb_antennas_rx; ap++) {
+              /* Add phase noise if enabled */
+              if (pdu_bit_map & PUSCH_PDU_BITMAP_PUSCH_PTRS) {
+                phase_noise(ts, &((int16_t*)&UE->common_vars.txdata[ap][slot_offset])[(i<<1)],
+                            &((int16_t*)&UE->common_vars.txdata[ap][slot_offset])[(i<<1)+1]);
+              }
+              ((int16_t*) &gNB->common_vars.rxdata[ap][slot_offset])[(2*i) + (delay*2)]   = (int16_t)((double)(((int16_t *)&UE->common_vars.txdata[ap][slot_offset])[(i<<1)])/sqrt(scale)   + (sqrt(sigma/2)*gaussdouble(0.0,1.0))); // convert to fixed point
+              ((int16_t*) &gNB->common_vars.rxdata[ap][slot_offset])[(2*i)+1 + (delay*2)]   = (int16_t)((double)(((int16_t *)&UE->common_vars.txdata[ap][slot_offset])[(i<<1)+1])/sqrt(scale) + (sqrt(sigma/2)*gaussdouble(0.0,1.0)));
+            }
+          }
+        }
 	else {
 	  AssertFatal(frame_parms->nb_antennas_rx == 1, "nb_ant != 1\n");
 	  // 800 samples is N_TA_OFFSET for FR1 @ 30.72 Ms/s,
@@ -825,6 +830,10 @@ int main(int argc, char **argv)
 		&gNB->pusch_vars[0]->ul_ch_estimates_ext[0][(start_symbol+1)*NR_NB_SC_PER_RB * pusch_pdu->rb_size],(nb_symb_sch-1)*NR_NB_SC_PER_RB * pusch_pdu->rb_size,1,1);
 	  LOG_M("rxsigF0_comp.m","rxsF0_comp",
 		&gNB->pusch_vars[0]->rxdataF_comp[0][(start_symbol+1)*NR_NB_SC_PER_RB * pusch_pdu->rb_size],(nb_symb_sch-1)*NR_NB_SC_PER_RB * pusch_pdu->rb_size,1,1);
+#ifdef DEBUG_UL_PTRS
+          LOG_M("rxdataF_ptrs_comp.m","ptrs_comp",
+                &gNB->pusch_vars[0]->rxdataF_ptrs_comp[0][(start_symbol+1)*NR_NB_SC_PER_RB * pusch_pdu->rb_size],(nb_symb_sch-1)*NR_NB_SC_PER_RB * pusch_pdu->rb_size,1,1);
+#endif
 	}
         start_meas(&gNB->phy_proc_rx);
         ////////////////////////////////////////////////////////////
@@ -902,6 +911,7 @@ int main(int argc, char **argv)
       if (print_perf==1) {
         printDistribution(&gNB->phy_proc_rx,table_rx,"Total PHY proc rx");
         printStatIndent(&gNB->ulsch_channel_estimation_stats,"ULSCH channel estimation time");
+        printStatIndent(&gNB->ulsch_ptrs_processing_stats,"ULSCH PTRS Processing time");
         printStatIndent(&gNB->ulsch_rbs_extraction_stats,"ULSCH rbs extraction time");
         printStatIndent(&gNB->ulsch_channel_compensation_stats,"ULSCH channel compensation time");
         printStatIndent(&gNB->ulsch_llr_stats,"ULSCH llr computation");

openair1/SIMULATION/TOOLS/phase_noise.c

+/*
+ * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The OpenAirInterface Software Alliance licenses this file to You under
+ * the OAI Public License, Version 1.1  (the "License"); you may not use this file
+ * except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.openairinterface.org/?page_id=698
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *-------------------------------------------------------------------------------
+ * For more information about the OpenAirInterface (OAI) Software Alliance:
+ *      contact@openairinterface.org
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <math.h>
+#include <time.h>
+#include  "sim.h"
+
+
+/* linear phase noise model */
+void phase_noise(double ts, int16_t * InRe, int16_t * InIm)
+{
+  double fd = 300;//0.01*30000
+  static double i=0;
+  double real, imag,x ,y;
+  i++;
+  real = cos(fd * 2 * M_PI * i * ts);
+  imag = sin (fd * 2 * M_PI * i * ts);
+  x = ((real * (double)InRe[0]) - (imag * (double)InIm[0])) ;
+  y= ((real * (double)InIm[0]) + (imag * (double)InRe[0])) ;
+  InRe[0]= (int16_t)(x);
+  InIm[0]= (int16_t)(y);
+}

openair1/SIMULATION/TOOLS/sim.h

@@ -440,6 +440,14 @@ void init_channelmod(void) ;
 double N_RB2sampling_rate(uint16_t N_RB);
 double N_RB2channel_bandwidth(uint16_t N_RB);
 
+/* Linear phase noise model */
+/*!
+  \brief This function produce phase noise and add to input signal
+  \param ts Sampling time 
+  \param *Re *Im Real and Imag part of the signal
+*/
+void phase_noise(double ts, int16_t * InRe, int16_t * InIm);
+
 #include "targets/RT/USER/rfsim.h"
 
 void do_DL_sig(sim_t *sim,