1 files changed, 113 insertions, 0 deletions
diff --git a/gr-trellis/src/examples/python/test_tcm_parallel.py b/gr-trellis/src/examples/python/test_tcm_parallel.py
new file mode 100755
index 000000000..0372351aa
--- /dev/null
+++ b/gr-trellis/src/examples/python/test_tcm_parallel.py
@@ -0,0 +1,113 @@
+#!/usr/bin/env python
+
+from gnuradio import gr
+from gnuradio import trellis, digital
+from gnuradio import eng_notation
+import math
+import sys
+import fsm_utils
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+
+
+def run_test (f,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed,P):
+    tb = gr.top_block ()
+
+    # TX
+    src = gr.lfsr_32k_source_s()
+    src_head = gr.head (gr.sizeof_short,Kb/16*P) # packet size in shorts
+    s2fsmi=gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality
+    s2p = gr.stream_to_streams(gr.sizeof_short,P) # serial to parallel
+    enc = trellis.encoder_ss(f,0) # initiali state = 0
+    mod = gr.chunks_to_symbols_sf(constellation,dimensionality)
+
+    # CHANNEL
+    add=[]
+    noise=[]
+    for i in range(P):
+        add.append(gr.add_ff())
+        noise.append(gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed))
+
+    # RX
+    metrics = trellis.metrics_f(f.O(),dimensionality,constellation,digital.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.
+    p2s = gr.streams_to_stream(gr.sizeof_short,P) # parallel to serial
+    fsmi2s=gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts
+    dst = gr.check_lfsr_32k_s()
+
+    tb.connect (src,src_head,s2fsmi,s2p)
+    for i in range(P):
+        tb.connect ((s2p,i),(enc,i),(mod,i))
+        tb.connect ((mod,i),(add[i],0))
+        tb.connect (noise[i],(add[i],1))
+        tb.connect (add[i],(metrics,i))
+        tb.connect ((metrics,i),(va,i),(p2s,i))
+    tb.connect (p2s,fsmi2s,dst)
+
+
+    tb.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 ()
+
+    return (ntotal,ntotal-nright)
+
+
+
+def main():
+    parser = OptionParser(option_class=eng_option)
+    parser.add_option("-f", "--fsm_file", type="string", default="fsm_files/awgn1o2_4.fsm", help="Filename containing the fsm specification, e.g. -f fsm_files/awgn1o2_4.fsm (default=fsm_files/awgn1o2_4.fsm)")
+    parser.add_option("-e", "--esn0", type="eng_float", default=10.0, help="Symbol energy to noise PSD level ratio in dB, e.g., -e 10.0 (default=10.0)")
+    parser.add_option("-r", "--repetitions", type="int", default=100, help="Number of packets to be generated for the simulation, e.g., -r 100 (default=100)")
+
+    (options, args) = parser.parse_args ()
+    if len(args) != 0:
+        parser.print_help()
+        raise SystemExit, 1
+
+    fname=options.fsm_file
+    esn0_db=float(options.esn0)
+    rep=int(options.repetitions)
+
+    # system parameters
+    f=trellis.fsm(fname) # get the FSM specification from a file
+    P=4  # how many parallel streams?
+    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),P) # 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()
+