transceiver: Add an option to generate random Access Bursts.

GSM/GSMCommon.cpp

@@ -56,6 +56,9 @@ const BitVector GSM::gDummyBurst("0001111101101110110000010100100111000001001000
 
 const BitVector GSM::gRACHSynchSequence("01001011011111111001100110101010001111000");
 
+//                               |-head-||---------midamble----------------------||--------------data----------------||t|
+const BitVector GSM::gRACHBurst("0011101001001011011111111001100110101010001111000110111101111110000111001001010110011000");
+
 
 int32_t GSM::FNDelta(int32_t v1, int32_t v2)
 {

GSM/GSMCommon.h

@@ -53,6 +53,8 @@ extern const BitVector gDummyBurst;
 
 /** Random access burst synch. sequence */
 extern const BitVector gRACHSynchSequence;
+/** Random access burst synch. sequence, GSM 05.02 5.2.7 */
+extern const BitVector gRACHBurst;
 
 
 /**@name Modulus operations for frame numbers. */

Transceiver52M/Transceiver.cpp

@@ -90,6 +90,9 @@ bool TransceiverState::init(int filler, size_t sps, float scale, size_t rtsc)
       case Transceiver::FILLER_EDGE_RAND:
         burst = generateEdgeBurst(rtsc);
         break;
+      case Transceiver::FILLER_ACCESS_RAND:
+        burst = genRandAccessBurst(sps, n);
+        break;
       case Transceiver::FILLER_ZERO:
       default:
         burst = generateEmptyBurst(sps, n);

Transceiver52M/Transceiver.h

@@ -156,6 +156,7 @@ public:
     FILLER_ZERO,
     FILLER_NORM_RAND,
     FILLER_EDGE_RAND,
+    FILLER_ACCESS_RAND,
   };
 
 private:

Transceiver52M/osmo-trx.cpp

@@ -187,6 +187,9 @@ bool trx_setup_config(struct trx_config *config)
 	case Transceiver::FILLER_EDGE_RAND:
 		fillstr = "EDGE busrts with random payload";
 		break;
+	case Transceiver::FILLER_ACCESS_RAND:
+		fillstr = "Access busrts with random payload";
+		break;
 	}
 
 	std::ostringstream ost("");
@@ -319,6 +322,7 @@ static void print_help()
 		"  -f    Enable C0 filler table\n"
 		"  -o    Set baseband frequency offset (default=auto)\n"
 		"  -r    Random burst test mode with TSC\n"
+		"  -A    Random burst test mode with Access Bursts\n"
 		"  -R    RSSI to dBm offset in dB (default=0)\n"
 		"  -S    Swap channels (UmTRX only)\n",
 		"EMERG, ALERT, CRT, ERR, WARNING, NOTICE, INFO, DEBUG");
@@ -341,7 +345,7 @@ static void handle_options(int argc, char **argv, struct trx_config *config)
 	config->swap_channels = false;
 	config->edge = false;
 
-	while ((option = getopt(argc, argv, "ha:l:i:p:c:dxfo:s:r:R:Se")) != -1) {
+	while ((option = getopt(argc, argv, "ha:l:i:p:c:dxfo:s:r:AR:Se")) != -1) {
 		switch (option) {
 		case 'h':
 			print_help();
@@ -381,6 +385,9 @@ static void handle_options(int argc, char **argv, struct trx_config *config)
 			config->rtsc = atoi(optarg);
 			config->filler = Transceiver::FILLER_NORM_RAND;
 			break;
+		case 'A':
+			config->filler = Transceiver::FILLER_ACCESS_RAND;
+			break;
 		case 'R':
 			config->rssi_offset = atof(optarg);
 			break;

Transceiver52M/sigProcLib.cpp

@@ -1005,6 +1005,39 @@ signalVector *genRandNormalBurst(int tsc, int sps, int tn)
   return burst;
 }
 
+/*
+ * Generate a random GSM access burst.
+ */
+signalVector *genRandAccessBurst(int sps, int tn)
+{
+  if ((tn < 0) || (tn > 7))
+    return NULL;
+  if ((sps != 1) && (sps != 4))
+    return NULL;
+
+  int i = 0;
+  BitVector *bits = new BitVector(88);
+  signalVector *burst;
+
+  /* head and synch bits */
+  for (int n = 0; i < 49; i++, n++)
+    (*bits)[i] = gRACHBurst[n];
+
+  /* Random bits */
+  for (; i < 85; i++)
+    (*bits)[i] = rand() % 2;
+
+  /* Tail bits */
+  for (; i < 88; i++)
+    (*bits)[i] = 0;
+
+  int guard = 68 + !(tn % 4);
+  burst = modulateBurst(*bits, guard, sps);
+  delete bits;
+
+  return burst;
+}
+
 signalVector *generateEmptyBurst(int sps, int tn)
 {
 	if ((tn < 0) || (tn > 7))

Transceiver52M/sigProcLib.h

@@ -122,6 +122,9 @@ signalVector *generateEmptyBurst(int sps, int tn);
 /** Generate a normal GSM burst with random payload - 4 or 1 SPS */
 signalVector *genRandNormalBurst(int tsc, int sps, int tn);
 
+/** Generate an access GSM burst with random payload - 4 or 1 SPS */
+signalVector *genRandAccessBurst(int sps, int tn);
+
 /** Generate a dummy GSM burst - 4 or 1 SPS */
 signalVector *generateDummyBurst(int sps, int tn);