3 from gnuradio import gr
4 from gnuradio import audio
5 from gnuradio import trellis
6 from gnuradio import eng_notation
14 def make_rx(tb,fo,fi,dimensionality,constellation,K,interleaver,IT,Es,N0,type):
15 metrics_in = trellis.metrics_f(fi.O(),dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # data preprocessing to generate metrics for innner Viterbi
16 scale = gr.multiply_const_ff(1.0/N0)
17 gnd = gr.vector_source_f([0],True);
26 inter.append( trellis.permutation(interleaver.K(),interleaver.INTER(),fi.I(),gr.sizeof_float) )
27 siso_in.append( trellis.siso_f(fi,K,0,-1,True,False,type) )
28 deinter.append( trellis.permutation(interleaver.K(),interleaver.DEINTER(),fi.I(),gr.sizeof_float) )
30 siso_out.append( trellis.siso_f(fo,K,0,-1,False,True,type) )
32 siso_out.append( trellis.viterbi_s(fo,K,0,-1) ) # no soft outputs needed
35 tb.connect (gnd,inter[0])
36 tb.connect (metrics_in,scale)
37 tb.connect (scale,(siso_in[0],1))
42 tb.connect (metrics_in,(siso_in[it+1],1))
43 tb.connect (siso_in[it],deinter[it],(siso_out[it],1))
44 tb.connect (gnd,(siso_out[it],0))
45 tb.connect (siso_out[it],inter[it+1])
46 tb.connect (inter[it],(siso_in[it],0))
48 tb.connect (siso_in[it],deinter[it],siso_out[it])
49 tb.connect (inter[it],(siso_in[it],0))
51 return (metrics_in,siso_out[IT-1])
54 def run_test (fo,fi,interleaver,Kb,bitspersymbol,K,dimensionality,constellation,Es,N0,IT,seed):
59 src = gr.lfsr_32k_source_s()
60 src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts
61 s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the outer FSM input cardinality
62 enc_out = trellis.encoder_ss(fo,0) # initial state = 0
63 inter = trellis.permutation(interleaver.K(),interleaver.INTER(),1,gr.sizeof_short)
64 enc_in = trellis.encoder_ss(fi,0) # initial state = 0
65 mod = gr.chunks_to_symbols_sf(constellation,dimensionality)
69 noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed)
72 (head,tail) = make_rx(tb,fo,fi,dimensionality,constellation,K,interleaver,IT,Es,N0,trellis.TRELLIS_MIN_SUM)
73 #(head,tail) = make_rx(tb,fo,fi,dimensionality,constellation,K,interleaver,IT,Es,N0,trellis.TRELLIS_SUM_PRODUCT)
74 fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts
75 dst = gr.check_lfsr_32k_s()
77 tb.connect (src,src_head,s2fsmi,enc_out,inter,enc_in,mod)
78 tb.connect (mod,(add,0))
79 tb.connect (noise,(add,1))
81 tb.connect (tail,fsmi2s,dst)
85 #print enc_out.ST(), enc_in.ST()
87 ntotal = dst.ntotal ()
88 nright = dst.nright ()
89 runlength = dst.runlength ()
90 return (ntotal,ntotal-nright)
98 esn0_db=float(args[2]) # Es/No in dB
99 rep=int(args[3]) # number of times the experiment is run to collect enough errors
101 sys.stderr.write ('usage: test_tcm.py fsm_name_out fsm_fname_in Es/No_db repetitions\n')
105 Kb=1024*16 # packet size in bits (make it multiple of 16 so it can be packed in a short)
106 fo=trellis.fsm(fname_out) # get the outer FSM specification from a file
107 fi=trellis.fsm(fname_in) # get the innner FSM specification from a file
108 bitspersymbol = int(round(math.log(fo.I())/math.log(2))) # bits per FSM input symbol
110 sys.stderr.write ('Incompatible cardinality between outer and inner FSM.\n')
112 K=Kb/bitspersymbol # packet size in trellis steps
113 interleaver=trellis.interleaver(K,666) # construct a random interleaver
114 modulation = fsm_utils.psk8 # see fsm_utlis.py for available predefined modulations
115 dimensionality = modulation[0]
116 constellation = modulation[1]
117 if len(constellation)/dimensionality != fi.O():
118 sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n')
120 # calculate average symbol energy
122 for i in range(len(constellation)):
123 Es = Es + constellation[i]**2
124 Es = Es / (len(constellation)/dimensionality)
125 N0=Es/pow(10.0,esn0_db/10.0); # calculate noise variance
126 IT = 3 # number of turbo iterations
128 tot_s=0 # total number of transmitted shorts
129 terr_s=0 # total number of shorts in error
130 terr_p=0 # total number of packets in error
132 (s,e)=run_test(fo,fi,interleaver,Kb,bitspersymbol,K,dimensionality,constellation,Es,N0,IT,-long(666+i)) # run experiment with different seed to get different noise realizations
135 terr_p=terr_p+(terr_s!=0)
136 if ((i+1)%10==0): # display progress
137 print i+1,terr_p, '%.2e' % ((1.0*terr_p)/(i+1)),tot_s,terr_s, '%.2e' % ((1.0*terr_s)/tot_s)
138 # estimate of the (short or bit) error rate
139 print rep,terr_p, '%.2e' % ((1.0*terr_p)/(i+1)),tot_s,terr_s, '%.2e' % ((1.0*terr_s)/tot_s)
142 if __name__ == '__main__':