1 files changed, 118 insertions, 0 deletions
diff --git a/gr-trellis/src/examples/test_tcm.py b/gr-trellis/src/examples/test_tcm.py
new file mode 100755
index 000000000..f22501558
--- /dev/null
+++ b/gr-trellis/src/examples/test_tcm.py
@@ -0,0 +1,118 @@
+#!/usr/bin/env python
+
+from gnuradio import gr
+from gnuradio import audio
+from gnuradio import trellis
+from gnuradio import eng_notation
+import math
+import sys
+import random
+import fsm_utils
+
+def run_test (f,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed):
+    fg = gr.flow_graph ()
+
+
+    # TX
+    #packet = [0]*Kb
+    #for i in range(Kb-1*16): # last 16 bits = 0 to drive the final state to 0
+        #packet[i] = random.randint(0, 1) # random 0s and 1s
+    #src = gr.vector_source_s(packet,False)
+    src = gr.lfsr_32k_source_s()
+    src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts
+    #b2s = gr.unpacked_to_packed_ss(1,gr.GR_MSB_FIRST) # pack bits in shorts
+    s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality
+    enc = trellis.encoder_ss(f,0) # initial state = 0
+    mod = gr.chunks_to_symbols_sf(constellation,dimensionality)
+
+    # CHANNEL
+    add = gr.add_ff()
+    noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed)
+
+    # RX
+    metrics = trellis.metrics_f(f.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for Viterbi
+    va = trellis.viterbi_s(f,K,0,-1) # Put -1 if the Initial/Final states are not set.
+    fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts
+    #s2b = gr.packed_to_unpacked_ss(1,gr.GR_MSB_FIRST) # unpack shorts to bits
+    #dst = gr.vector_sink_s(); 
+    dst = gr.check_lfsr_32k_s()
+    
+
+    fg.connect (src,src_head,s2fsmi,enc,mod)
+    #fg.connect (src,b2s,s2fsmi,enc,mod)
+    fg.connect (mod,(add,0))
+    fg.connect (noise,(add,1))
+    fg.connect (add,metrics)
+    fg.connect (metrics,va,fsmi2s,dst)
+    #fg.connect (metrics,va,fsmi2s,s2b,dst)
+    
+
+    fg.run()
+    
+    # A bit of cheating: run the program once and print the 
+    # final encoder state..
+    # Then put it as the last argument in the viterbi block
+    #print "final state = " , enc.ST()
+
+    ntotal = dst.ntotal ()
+    nright = dst.nright ()
+    runlength = dst.runlength ()
+    #ntotal = len(packet)
+    #if len(dst.data()) != ntotal:
+        #print "Error: not enough data\n"
+    #nright = 0;
+    #for i in range(ntotal):
+        #if packet[i]==dst.data()[i]:
+            #nright=nright+1
+        #else:
+            #print "Error in ", i
+    return (ntotal,ntotal-nright)
+
+
+
+
+def main(args):
+    nargs = len (args)
+    if nargs == 3:
+        fname=args[0]
+        esn0_db=float(args[1]) # Es/No in dB
+        rep=int(args[2]) # number of times the experiment is run to collect enough errors
+    else:
+        sys.stderr.write ('usage: test_tcm.py fsm_fname Es/No_db  repetitions\n')
+        sys.exit (1)
+
+    # system parameters
+    f=trellis.fsm(fname) # get the FSM specification from a file
+    Kb=1024*16  # packet size in bits (make it multiple of 16 so it can be packed in a short)
+    bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol
+    K=Kb/bitspersymbol # packet size in trellis steps
+    modulation = fsm_utils.psk4 # see fsm_utlis.py for available predefined modulations
+    dimensionality = modulation[0]
+    constellation = modulation[1] 
+    if len(constellation)/dimensionality != f.O():
+        sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n')
+        sys.exit (1)
+    # calculate average symbol energy
+    Es = 0
+    for i in range(len(constellation)):
+        Es = Es + constellation[i]**2
+    Es = Es / (len(constellation)/dimensionality)
+    N0=Es/pow(10.0,esn0_db/10.0); # calculate noise variance
+    
+    tot_s=0 # total number of transmitted shorts
+    terr_s=0 # total number of shorts in error
+    terr_p=0 # total number of packets in error
+    for i in range(rep):
+        (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations
+        tot_s=tot_s+s
+        terr_s=terr_s+e
+        terr_p=terr_p+(terr_s!=0)
+        if ((i+1)%100==0) : # display progress
+            print i+1,terr_p, '%.2e' % ((1.0*terr_p)/(i+1)),tot_s,terr_s, '%.2e' % ((1.0*terr_s)/tot_s)
+    # estimate of the (short or bit) error rate
+    print rep,terr_p, '%.2e' % ((1.0*terr_p)/(i+1)),tot_s,terr_s, '%.2e' % ((1.0*terr_s)/tot_s)
+
+
+
+if __name__ == '__main__':
+    main (sys.argv[1:])