3 from gnuradio import gr
4 from gnuradio import audio
5 from gnuradio import trellis
6 from gnuradio import eng_notation
15 def run_test (fo,fi,interleaver,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed):
20 src = gr.lfsr_32k_source_s()
21 src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts
22 s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the outer FSM input cardinality
23 enc_out = trellis.encoder_ss(fo,0) # initial state = 0
24 inter = trellis.permutation(interleaver.K(),interleaver.INTER(),1,gr.sizeof_short)
25 enc_in = trellis.encoder_ss(fi,0) # initial state = 0
26 mod = gr.chunks_to_symbols_sf(constellation,dimensionality)
30 noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed)
33 metrics_in = trellis.metrics_f(fi.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for innner Viterbi
34 gnd = gr.vector_source_f([0],True);
35 siso_in = trellis.siso_f(fi,K,0,-1,True,False,trellis.TRELLIS_MIN_SUM) # Put -1 if the Initial/Final states are not set.
36 deinter = trellis.permutation(interleaver.K(),interleaver.DEINTER(),fi.I(),gr.sizeof_float)
37 va_out = trellis.viterbi_s(fo,K,0,-1) # Put -1 if the Initial/Final states are not set.
38 fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts
39 dst = gr.check_lfsr_32k_s()
41 tb.connect (src,src_head,s2fsmi,enc_out,inter,enc_in,mod)
42 tb.connect (mod,(add,0))
43 tb.connect (noise,(add,1))
44 tb.connect (add,metrics_in)
45 tb.connect (gnd,(siso_in,0))
46 tb.connect (metrics_in,(siso_in,1))
47 tb.connect (siso_in,deinter,va_out,fsmi2s,dst)
51 ntotal = dst.ntotal ()
52 nright = dst.nright ()
53 runlength = dst.runlength ()
54 return (ntotal,ntotal-nright)
62 esn0_db=float(args[2]) # Es/No in dB
63 rep=int(args[3]) # number of times the experiment is run to collect enough errors
65 sys.stderr.write ('usage: test_tcm.py fsm_name_out fsm_fname_in Es/No_db repetitions\n')
69 Kb=1024*16 # packet size in bits (make it multiple of 16 so it can be packed in a short)
70 fo=trellis.fsm(fname_out) # get the outer FSM specification from a file
71 fi=trellis.fsm(fname_in) # get the innner FSM specification from a file
72 bitspersymbol = int(round(math.log(fo.I())/math.log(2))) # bits per FSM input symbol
74 sys.stderr.write ('Incompatible cardinality between outer and inner FSM.\n')
76 K=Kb/bitspersymbol # packet size in trellis steps
77 interleaver=trellis.interleaver(K,666) # construct a random interleaver
78 modulation = fsm_utils.psk8 # see fsm_utlis.py for available predefined modulations
79 dimensionality = modulation[0]
80 constellation = modulation[1]
81 if len(constellation)/dimensionality != fi.O():
82 sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n')
84 # calculate average symbol energy
86 for i in range(len(constellation)):
87 Es = Es + constellation[i]**2
88 Es = Es / (len(constellation)/dimensionality)
89 N0=Es/pow(10.0,esn0_db/10.0); # calculate noise variance
92 tot_s=0 # total number of transmitted shorts
93 terr_s=0 # total number of shorts in error
94 terr_p=0 # total number of packets in error
96 (s,e)=run_test(fo,fi,interleaver,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations
99 terr_p=terr_p+(terr_s!=0)
100 if ((i+1)%100==0) : # display progress
101 print i+1,terr_p, '%.2e' % ((1.0*terr_p)/(i+1)),tot_s,terr_s, '%.2e' % ((1.0*terr_s)/tot_s)
102 # estimate of the (short or bit) error rate
103 print rep,terr_p, '%.2e' % ((1.0*terr_p)/(i+1)),tot_s,terr_s, '%.2e' % ((1.0*terr_s)/tot_s)
107 if __name__ == '__main__':