3 from gnuradio import gr
4 from gnuradio import audio
5 from gnuradio import trellis
6 from gnuradio import eng_notation
11 def run_test (f,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed):
15 src = gr.lfsr_32k_source_s()
16 src_head = gr.head (gr.sizeof_short,Kb/16) # packet size in shorts
17 s2fsmi = gr.packed_to_unpacked_ss(bitspersymbol,gr.GR_MSB_FIRST) # unpack shorts to symbols compatible with the FSM input cardinality
18 enc = trellis.encoder_ss(f,0) # initial state = 0
19 mod = gr.chunks_to_symbols_sf(constellation,dimensionality)
24 noise = gr.noise_source_f(gr.GR_GAUSSIAN,math.sqrt(N0/2),seed)
28 va = trellis.viterbi_combined_fs(f,K,0,-1,dimensionality,constellation,trellis.TRELLIS_EUCLIDEAN) # Put -1 if the Initial/Final states are not set.
29 fsmi2s = gr.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts
30 dst = gr.check_lfsr_32k_s();
33 tb.connect (src,src_head,s2fsmi,enc,mod)
34 tb.connect (mod,(add,0))
35 tb.connect (noise,(add,1))
36 tb.connect (add,va,fsmi2s,dst)
41 # A bit of cheating: run the program once and print the
42 # final encoder state..
43 # Then put it as the last argument in the viterbi block
44 #print "final state = " , enc.ST()
46 ntotal = dst.ntotal ()
47 nright = dst.nright ()
48 runlength = dst.runlength ()
50 return (ntotal,ntotal-nright)
59 esn0_db=float(args[1]) # Es/No in dB
60 rep=int(args[2]) # number of times the experiment is run to collect enough errors
62 sys.stderr.write ('usage: test_tcm_combined.py fsm_fname Es/No_db repetitions\n')
66 f=trellis.fsm(fname) # get the FSM specification from a file (will hopefully be automated in the future...)
67 Kb=1024*16 # packet size in bits (make it multiple of 16)
68 bitspersymbol = int(round(math.log(f.I())/math.log(2))) # bits per FSM input symbol
69 K=Kb/bitspersymbol # packet size in trellis steps
70 modulation = fsm_utils.psk4 # see fsm_utils.py for available predefined modulations
71 dimensionality = modulation[0]
72 constellation = modulation[1]
73 if len(constellation)/dimensionality != f.O():
74 sys.stderr.write ('Incompatible FSM output cardinality and modulation size.\n')
76 # calculate average symbol energy
78 for i in range(len(constellation)):
79 Es = Es + constellation[i]**2
80 Es = Es / (len(constellation)/dimensionality)
81 N0=Es/pow(10.0,esn0_db/10.0); # noise variance
83 tot_s=0 # total number of transmitted shorts
84 terr_s=0 # total number of shorts in error
85 terr_p=0 # total number of packets in error
87 (s,e)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-long(666+i)) # run experiment with different seed to get different noise realizations
90 terr_p=terr_p+(terr_s!=0)
91 if ((i+1)%100==0) : # display progress
92 print i+1,terr_p, '%.2e' % ((1.0*terr_p)/(i+1)),tot_s,terr_s, '%.2e' % ((1.0*terr_s)/tot_s)
93 # estimate of the (short or bit) error rate
94 print rep,terr_p, '%.2e' % ((1.0*terr_p)/(i+1)),tot_s,terr_s, '%.2e' % ((1.0*terr_s)/tot_s)
98 if __name__ == '__main__':