12-bit frequency-domain equalizer LUT. fix for log2_maxh in ULSCH receiver

openair1/PHY/INIT/lte_init.c

@@ -425,6 +425,7 @@ int phy_init_lte_eNB(PHY_VARS_eNB *eNB,
   generate_phich_reg_mapping (fp);
   init_sss();
 
+  init_fde();
   for (UE_id = 0; UE_id < NUMBER_OF_UE_MAX; UE_id++) {
     eNB->first_run_timing_advance[UE_id] =
       1;   ///This flag used to be static. With multiple eNBs this does no longer work, hence we put it in the structure. However it has to be initialized with 1, which is performed here.

openair1/PHY/LTE_ESTIMATION/freq_equalization.c

@@ -22,8 +22,8 @@
 #include "PHY/defs_eNB.h"
 #include "PHY/sse_intrin.h"
 
-// This is 512/(1:256) in __m128i format
-int16_t inv_ch[256*8] = {512,512,512,512,512,512,512,512,
+// This is 4096/(1:4096) in __m128i format
+__m128i inv_ch[4096];/* = {512,512,512,512,512,512,512,512,
                          256,256,256,256,256,256,256,256,
                          170,170,170,170,170,170,170,170,
                          128,128,128,128,128,128,128,128,
@@ -279,7 +279,11 @@ int16_t inv_ch[256*8] = {512,512,512,512,512,512,512,512,
                          2,2,2,2,2,2,2,2,
                          2,2,2,2,2,2,2,2,
                          2,2,2,2,2,2,2,2,
-                        };
+                        };*/
+
+void init_fde() {
+  for (int i=1;i<4096;i++) inv_ch[i] = _mm_set1_epi16(4096/i);
+}
 
 void freq_equalization(LTE_DL_FRAME_PARMS *frame_parms,
                        int32_t **rxdataF_comp,
@@ -312,12 +316,12 @@ void freq_equalization(LTE_DL_FRAME_PARMS *frame_parms,
 
     amp=(*((int16_t*)&ul_ch_mag128[re]));
 
-    if (amp>255)
-      amp=255;
+    if (amp>4095)
+      amp=4095;
 
-    //     printf("freq_eq: symbol %d re %d => %d,%d,%d, (%d) (%d,%d) => ",symbol,re,*((int16_t*)(&ul_ch_mag128[re])),amp,inv_ch[8*amp],*((int16_t*)(&ul_ch_mag128[re]))*inv_ch[8*amp],*(int16_t*)&(rxdataF_comp128[re]),*(1+(int16_t*)&(rxdataF_comp128[re])));
+    //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,_mm_extract_epi16(inv_ch[amp],0),(*((int16_t*)(&ul_ch_mag128[re]))*_mm_extract_epi16(inv_ch[amp],0))>>3,*(int16_t*)&(rxdataF_comp128[re]),*(1+(int16_t*)&(rxdataF_comp128[re])));
 #if defined(__x86_64__) || defined(__i386__)
-    rxdataF_comp128[re] = _mm_mullo_epi16(rxdataF_comp128[re],*((__m128i *)&inv_ch[8*amp]));
+    rxdataF_comp128[re] = _mm_srai_epi16(_mm_mullo_epi16(rxdataF_comp128[re],inv_ch[amp]),3);
 
     if (Qm==4)
       ul_ch_mag128[re]  = _mm_set1_epi16(324);  // this is 512*2/sqrt(10)
@@ -326,7 +330,7 @@ void freq_equalization(LTE_DL_FRAME_PARMS *frame_parms,
       ul_ch_magb128[re] = _mm_set1_epi16(158);  // this is 512*2/sqrt(42)
     }
 #elif defined(__arm__)
-    rxdataF_comp128[re] = vmulq_s16(rxdataF_comp128[re],*((int16x8_t *)&inv_ch[8*amp]));
+    rxdataF_comp128[re] = vmulq_s16(rxdataF_comp128[re],inv_ch[amp]);
 
     if (Qm==4)
       ul_ch_mag128[re]  = vdupq_n_s16(324);  // this is 512*2/sqrt(10)

openair1/PHY/LTE_ESTIMATION/lte_estimation.h

@@ -288,6 +288,7 @@ void freq_equalization(LTE_DL_FRAME_PARMS *frame_parms,
                        unsigned short Msc_RS,
                        unsigned char Qm);
 
+void init_fde(void);
 
 void dump_I0_stats(FILE *fd,PHY_VARS_eNB *eNB);
 /** @} */

openair1/PHY/LTE_TRANSPORT/ulsch_demodulation.c

@@ -514,7 +514,6 @@ void ulsch_16qam_llr(LTE_DL_FRAME_PARMS *frame_parms,
   for (i=0; i<(nb_rb*3); i++) {
 #if defined(__x86_64__) || defined(__i386__)
     mmtmpU0 = _mm_abs_epi16(rxF[i]);
-    //    print_shorts("tmp0",&tmp0);
     mmtmpU0 = _mm_subs_epi16(ch_mag[i],mmtmpU0);
     (*llrp128)[0] = _mm_unpacklo_epi32(rxF[i],mmtmpU0);
     (*llrp128)[1] = _mm_unpackhi_epi32(rxF[i],mmtmpU0);
@@ -1160,8 +1159,7 @@ void rx_ulsch(PHY_VARS_eNB *eNB,
   for (aarx=0; aarx<frame_parms->nb_antennas_rx; aarx++)
     avgs = cmax(avgs,avgU[aarx]);
 
-  //      log2_maxh = 4+(log2_approx(avgs)/2);
-  log2_maxh = (log2_approx(avgs)/2); //+ log2_approx(frame_parms->nb_antennas_rx-1)+4;
+  log2_maxh = 4+(log2_approx(avgs)/2); 
   LOG_D(PHY,"[ULSCH] log2_maxh = %d (%d,%d)\n",log2_maxh,avgU[0],avgs);
 
   for (l=0; l<(frame_parms->symbols_per_tti-ulsch[UE_id]->harq_processes[harq_pid]->srs_active); l++) {