Feat / add frequency equalization for 16/64QAM with transform precoding

CMakeLists.txt

@@ -1179,6 +1179,7 @@ set(PHY_SRC_UE
   ${OPENAIR1_DIR}/PHY/NR_REFSIG/ptrs_nr.c
   ${OPENAIR1_DIR}/PHY/NR_UE_ESTIMATION/filt16a_32.c
   ${OPENAIR1_DIR}/PHY/NR_ESTIMATION/nr_ul_channel_estimation.c
+  ${OPENAIR1_DIR}/PHY/NR_ESTIMATION/nr_freq_equalization.c
   ${OPENAIR1_DIR}/PHY/NR_ESTIMATION/nr_measurements_gNB.c
   ${OPENAIR1_DIR}/PHY/TOOLS/file_output.c
   ${OPENAIR1_DIR}/PHY/TOOLS/cadd_vv.c

openair1/PHY/INIT/nr_init.c

@@ -28,6 +28,7 @@
 #include "PHY/CODING/nrPolar_tools/nr_polar_pbch_defs.h"
 #include "PHY/NR_TRANSPORT/nr_transport_proto.h"
 #include "PHY/NR_TRANSPORT/nr_transport_common_proto.h"
+#include "PHY/NR_ESTIMATION/nr_ul_estimation.h"
 #include "openair1/PHY/MODULATION/nr_modulation.h"
 #include "openair1/PHY/defs_RU.h"
 #include "openair1/PHY/CODING/nrLDPC_extern.h"
@@ -536,6 +537,8 @@ int phy_init_nr_gNB(PHY_VARS_gNB *gNB)
   init_scrambling_luts();
   init_pucch2_luts();
 
+  nr_init_fde(); // Init array for frequency equalization of transform precoding of PUSCH
+
   load_nrLDPClib(NULL);
 
   if (gNB->ldpc_offload_flag)

openair1/PHY/NR_ESTIMATION/nr_freq_equalization.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 "PHY/defs_eNB.h"
+#include "PHY/sse_intrin.h"
+#include "PHY/NR_ESTIMATION/nr_ul_estimation.h"
+
+// Reference of openair1/PHY/LTE_ESTIMATION/freq_equalization.c
+
+// This is 4096/(1:4096) in simde__m128i format
+simde__m128i nr_inv_ch[4096]={0};/* = {0, 4096/1, 4096/2, 4096/3, 4096/4...}*/
+
+void nr_init_fde() {
+  for (int i=1;i<4096;i++) nr_inv_ch[i] = simde_mm_set1_epi16(4096/i);
+}
+
+void nr_freq_equalization(NR_DL_FRAME_PARMS *frame_parms,
+                          int32_t *rxdataF_comp,
+                          int32_t *ul_ch_mag,
+                          int32_t *ul_ch_magb,
+                          uint8_t symbol,
+                          uint16_t Msc_RS,
+                          uint8_t Qm) {
+  uint16_t re;
+  int16_t amp;
+  size_t offset = frame_parms != NULL ? (symbol*frame_parms->N_RB_DL*12) : 0;
+
+  simde__m128i *rxdataF_comp128 = (simde__m128i *)&rxdataF_comp[offset];
+  simde__m128i *ul_ch_mag128    = (simde__m128i *)&ul_ch_mag[offset];
+  simde__m128i *ul_ch_magb128   = (simde__m128i *)&ul_ch_magb[offset];
+
+  if(frame_parms != NULL){
+    AssertFatal(symbol<frame_parms->symbols_per_slot,"symbol %d >= %d\n",
+                symbol,frame_parms->symbols_per_slot);
+    AssertFatal(Msc_RS<=frame_parms->N_RB_UL*12,"Msc_RS %d >= %d\n",
+                Msc_RS,frame_parms->N_RB_UL*12);
+  }
+
+  for (re=0; re<(Msc_RS>>2); re++) {
+    amp=(*((int16_t*)&ul_ch_mag128[re]));
+
+    if (amp>4095)
+      amp=4095;
+
+    //printf("freq_eq: symbol %d re %d => mag %d,amp %d,inv %d, prod %d (%d,%d)\n",symbol,re,*((int16_t*)(&ul_ch_mag128[re])),amp,simde_mm_extract_epi16(nr_inv_ch[amp],0),(*((int16_t*)(&ul_ch_mag128[re]))*simde_mm_extract_epi16(nr_inv_ch[amp],0))>>3,*(int16_t*)&(rxdataF_comp128[re]),*(1+(int16_t*)&(rxdataF_comp128[re])));
+    rxdataF_comp128[re] = simde_mm_srai_epi16(simde_mm_mullo_epi16(rxdataF_comp128[re],nr_inv_ch[amp]),3);
+
+    if (Qm == 4)
+      ul_ch_mag128[re]  = simde_mm_set1_epi16(324);  // this is 512*2/sqrt(10)
+    else if(Qm == 6){
+      ul_ch_mag128[re]  = simde_mm_set1_epi16(316);  // this is 512*4/sqrt(42)
+      ul_ch_magb128[re] = simde_mm_set1_epi16(158);  // this is 512*2/sqrt(42)
+    }
+    else if(Qm != 2)
+      AssertFatal(1, "nr_freq_equalization(), Qm = %d, should be 2, 4 or 6. symbol=%d, Msc_RS=%d\n", Qm, symbol, Msc_RS);
+
+    //            printf("(%d,%d)\n",*(int16_t*)&(rxdataF_comp128[re]),*(1+(int16_t*)&(rxdataF_comp128[re])));
+
+  }
+}

openair1/PHY/NR_ESTIMATION/nr_ul_estimation.h

@@ -86,4 +86,15 @@ int nr_srs_channel_estimation(const PHY_VARS_gNB *gNB,
                               int32_t srs_estimated_channel_time_shifted[][1<<srs_pdu->num_ant_ports][gNB->frame_parms.ofdm_symbol_size],
                               int8_t *snr_per_rb,
                               int8_t *snr);
+
+void nr_freq_equalization(NR_DL_FRAME_PARMS *frame_parms,
+                          int *rxdataF_comp,
+                          int *ul_ch_mag,
+                          int *ul_ch_mag_b,
+                          unsigned char symbol,
+                          unsigned short Msc_RS,
+                          unsigned char Qm);
+
+void nr_init_fde(void);
+
 #endif

openair1/PHY/NR_TRANSPORT/nr_ulsch_demodulation.c

@@ -2796,8 +2796,17 @@ void nr_pusch_symbol_processing_noprecoding(void *arg)
       }
 
       // Perform IDFT if transform precoding is enabled
-      // TODO: Frequency equalizer
       if(rel15_ul->transform_precoding == transformPrecoder_enabled){
+        // Perform frequency equalization
+        if(rel15_ul->qam_mod_order > 2){
+          nr_freq_equalization(NULL,
+                               rxF_comp,
+                               rxF_ch_mag,
+                               rxF_ch_magb,
+                               symbol,
+                               nb_re_pusch,
+                               rel15_ul->qam_mod_order);
+        }
         nr_idft(rxF_comp, nb_re_pusch);
       }
 

openair1/PHY/NR_UE_TRANSPORT/nr_ulsch_ue.c

@@ -472,7 +472,7 @@ void nr_ue_ulsch_procedures(PHY_VARS_NR_UE *UE,
 
         if (++k >= frame_parms->ofdm_symbol_size)
           k -= frame_parms->ofdm_symbol_size;
-      } //for (i=0; i< nb_rb*NR_NB_SC_PER_RB; i++) 
+      } //for (i=0; i< nb_rb*NR_NB_SC_PER_RB; i++)
     }//for (l=start_symbol; l<start_symbol+number_of_symbols; l++)
   }//for (nl=0; nl < Nl; nl++)