Added TA and beta options to PRACH example

lte/examples/prach_ue.c

@@ -65,6 +65,9 @@ typedef struct {
   int force_N_id_2;
   uint16_t rnti;
   uint32_t file_nof_prb;
+  float beta_prach;
+  float ta_usec; 
+  float beta_pusch; 
   char *uhd_args; 
   float uhd_rx_freq; 
   float uhd_tx_freq; 
@@ -78,6 +81,9 @@ void args_default(prog_args_t *args) {
   args->rnti = SIRNTI;
   args->force_N_id_2 = -1; // Pick the best
   args->file_nof_prb = 6; 
+  args->beta_prach = 0.2;
+  args->beta_pusch = 1.5;
+  args->ta_usec = -1.0;
   args->uhd_args = "";
   args->uhd_rx_freq = 2112500000.0;
   args->uhd_tx_freq = 1922500000.0;
@@ -87,12 +93,15 @@ void args_default(prog_args_t *args) {
 }
 
 void usage(prog_args_t *args, char *prog) {
-  printf("Usage: %s [agfFrlnv]\n", prog);
+  printf("Usage: %s [agfFbrlnv]\n", prog);
   printf("\t-a UHD args [Default %s]\n", args->uhd_args);
   printf("\t-g UHD TX/RX gain [Default %.2f dB]\n", args->uhd_rx_gain);
   printf("\t-G UHD TX/RX gain [Default %.2f dB]\n", args->uhd_tx_gain);
   printf("\t-f UHD RX freq [Default %.1f MHz]\n", args->uhd_rx_freq/1000000);
   printf("\t-F UHD TX freq [Default %.1f MHz]\n", args->uhd_tx_freq/1000000);
+  printf("\t-b beta PRACH (transmission amplitude) [Default %f]\n",args->beta_prach);
+  printf("\t-B beta PUSCH (transmission amplitude) [Default %f]\n",args->beta_pusch);
+  printf("\t-t TA usec (time advance, -1 from RAR) [Default %f]\n",args->ta_usec);
   printf("\t-r RNTI [Default 0x%x]\n",args->rnti);
   printf("\t-l Force N_id_2 [Default best]\n");
   printf("\t-n nof_subframes [Default %d]\n", args->nof_subframes);
@@ -102,11 +111,20 @@ void usage(prog_args_t *args, char *prog) {
 void parse_args(prog_args_t *args, int argc, char **argv) {
   int opt;
   args_default(args);
-  while ((opt = getopt(argc, argv, "agGfFrlnv")) != -1) {
+  while ((opt = getopt(argc, argv, "agGfFrlnvbBt")) != -1) {
     switch (opt) {
     case 'a':
       args->uhd_args = argv[optind];
       break;
+    case 'b':
+      args->beta_prach = atof(argv[optind]);
+      break;
+    case 'B':
+      args->beta_pusch = atof(argv[optind]);
+      break;
+    case 't':
+      args->ta_usec = atof(argv[optind]);
+      break;
     case 'g':
       args->uhd_rx_gain = atof(argv[optind]);
       break;
@@ -181,7 +199,7 @@ cf_t *sf_buffer = NULL;
 
 int generate_prach_sequences(){
   for(int i=0;i<NOF_PRACH_SEQUENCES;i++){
-    if(prach_gen(&prach, i, 0, prach_buffers[i])){
+    if(prach_gen(&prach, i, 0, prog_args.beta_prach, prach_buffers[i])){
       fprintf(stderr, "Error generating prach sequence\n");
       return -1;
     }
@@ -533,6 +551,9 @@ int main(int argc, char **argv) {
                 uint32_t n_ta = lte_N_ta_new_rar(rar_msg.timing_adv_cmd);
                 printf("ta: %d, n_ta: %d\n", rar_msg.timing_adv_cmd, n_ta);
                 float time_adv_sec = ((float) n_ta+15)/(15000.0*lte_symbol_sz(cell.nof_prb));
+                if (prog_args.ta_usec >= 0) {
+                  time_adv_sec = prog_args.ta_usec*1e-6;
+                }
 #define N_TX  5
                 const uint32_t rv[N_TX]={0,2,3,1,0};
                 for (int i=0; i<N_TX;i++) {
@@ -545,7 +566,7 @@ int main(int argc, char **argv) {
                     exit(-1);
                   }
                   
-                  vec_sc_prod_cfc(ul_signal, 1.5, ul_signal, SF_LEN_PRB(cell.nof_prb));
+                  vec_sc_prod_cfc(ul_signal, prog_args.beta_pusch, ul_signal, SF_LEN_PRB(cell.nof_prb));
                   /*
                   for (int i=0;i<7680;i++) {
                     if (i < 100) {

lte/phy/include/liblte/phy/phch/prach.h

@@ -95,6 +95,7 @@ LIBLTE_API int prach_init(prach_t *p,
 LIBLTE_API int prach_gen(prach_t *p,
                          uint32_t seq_index,
                          uint32_t freq_offset,
+                         float beta_prach,
                          cf_t *signal);
 
 LIBLTE_API int prach_detect(prach_t *p,

lte/phy/lib/phch/src/prach.c

@@ -317,14 +317,14 @@ int prach_init(prach_t *p,
       return LIBLTE_ERROR;
     }
     dft_plan_set_mirror(p->zc_fft, false);
-    dft_plan_set_norm(p->zc_fft, true);
+    dft_plan_set_norm(p->zc_fft, false);
 
     p->zc_ifft = (dft_plan_t*)vec_malloc(sizeof(dft_plan_t));
     if(dft_plan(p->zc_ifft, p->N_zc, BACKWARD, COMPLEX)){
       return LIBLTE_ERROR;
     }
     dft_plan_set_mirror(p->zc_ifft, false);
-    dft_plan_set_norm(p->zc_ifft, true);
+    dft_plan_set_norm(p->zc_ifft, false);
 
     // Generate our 64 sequences
     p->N_roots = 0;
@@ -371,6 +371,7 @@ int prach_init(prach_t *p,
 int prach_gen(prach_t *p,
               uint32_t seq_index,
               uint32_t freq_offset,
+              float beta_prach,
               cf_t *signal)
 {
   int ret = LIBLTE_ERROR;
@@ -401,7 +402,7 @@ int prach_gen(prach_t *p,
     }
                 
     // Normalize 
-    vec_sc_prod_cfc(signal, 1.0/sqrtf(p->N_ifft_prach*2), signal, (p->N_cp + p->N_seq));
+    vec_sc_prod_cfc(signal, beta_prach, signal, (p->N_cp + p->N_seq));
 
     ret = LIBLTE_SUCCESS;
   }

lte/phy/lib/phch/test/prach_test.c

@@ -77,6 +77,7 @@ int main(int argc, char **argv) {
     prach_gen(p,
               seq_index,
               frequency_offset,
+              0.2,
               preamble);
 
     uint32_t prach_len = p->N_seq;

lte/phy/lib/phch/test/prach_test_mex.c

@@ -97,7 +97,7 @@ void mexFunction(int nlhs, mxArray *plhs[], int nrhs, const mxArray *prhs[])
     return;
   }
   bzero(signal, sizeof(cf_t) * nof_samples);
-  if (prach_gen(&prach, seq_idx, frequency_offset, signal)) {
+  if (prach_gen(&prach, seq_idx, frequency_offset, 0.2, signal)) {
     mexErrMsgTxt("Error generating PRACH\n");
     return; 
   }

lte/phy/lib/phch/test/prach_test_multi.c

@@ -84,6 +84,7 @@ int main(int argc, char **argv) {
     prach_gen(p,
               seq_index,
               frequency_offset,
+              0.2,
               preamble);
 
     for(int i=0;i<p->N_cp+p->N_seq;i++)

matlab/tests/pusch_decode_test.m

@@ -1,7 +1,7 @@
-ueConfig=struct('NCellID',0,'NULRB',25,'NSubframe',4,'RNTI',122,'CyclicPrefixUL','Normal','NTxAnts',1);
+ueConfig=struct('NCellID',0,'NULRB',25,'NSubframe',4,'RNTI',109,'CyclicPrefixUL','Normal','NTxAnts',1);
 puschConfig=struct('NLayers',1,'OrthCover','Off','PRBSet',(19:22)','Modulation','QPSK','RV',0,'Shortened',0);
 
-subframe_rx=lteSCFDMADemodulate(ueConfig,x.*transpose(exp(-1i*2*pi*0.04*(1:length(x))/512)));
+subframe_rx=lteSCFDMADemodulate(ueConfig,x.*transpose(exp(-1i*2*pi*0.18*(1:length(x))/512)));
 idx=ltePUSCHIndices(ueConfig,puschConfig);
 pusch_rx=subframe_rx(idx);
 [hest, noiseest] = lteULChannelEstimate(ueConfig,puschConfig,subframe_rx);
@@ -9,3 +9,4 @@ ce=hest(idx);
 [cws,symbols] = ltePUSCHDecode(ueConfig,puschConfig,pusch_rx,ce,noiseest);
 [trblkout,blkcrc,stateout] = lteULSCHDecode(ueConfig,puschConfig,88,cws);
 disp(blkcrc)
+scatter(real(symbols),imag(symbols))