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#!/usr/bin/env python
from __future__ import print_function
from __future__ import division
from __future__ import unicode_literals
from gnuradio import gr
from gnuradio import trellis, digital, blocks
from gnuradio import eng_notation
import math
import sys
import random
from gnuradio.trellis import fsm_utils
from gnuradio.eng_option import eng_option
from optparse import OptionParser
import numpy
try:
from gnuradio import analog
except ImportError:
sys.stderr.write("Error: Program requires gr-analog.\n")
sys.exit(1)
def run_test (f,Kb,bitspersymbol,K,dimensionality,constellation,N0,seed):
tb = gr.top_block ()
# TX
numpy.random.seed(-seed)
packet = numpy.random.randint(0,2,Kb) # create Kb random bits
packet[Kb-10:Kb]=0
packet[0:Kb]=0
src = blocks.vector_source_s(packet.tolist(),False)
b2s = blocks.unpacked_to_packed_ss(1,gr.GR_MSB_FIRST) # pack bits in shorts
s2fsmi = blocks.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 = digital.chunks_to_symbols_sf(constellation,dimensionality)
# CHANNEL
add = blocks.add_ff()
noise = analog.noise_source_f(analog.GR_GAUSSIAN,math.sqrt(N0 / 2),int(seed))
# RX
va = trellis.viterbi_combined_fs(f,K,0,0,dimensionality,constellation,digital.TRELLIS_EUCLIDEAN) # Put -1 if the Initial/Final states are not set.
fsmi2s = blocks.unpacked_to_packed_ss(bitspersymbol,gr.GR_MSB_FIRST) # pack FSM input symbols to shorts
s2b = blocks.packed_to_unpacked_ss(1,gr.GR_MSB_FIRST) # unpack shorts to bits
dst = blocks.vector_sink_s();
tb.connect (src,b2s,s2fsmi,enc,mod)
tb.connect (mod,(add,0))
tb.connect (noise,(add,1))
tb.connect (add,va,fsmi2s,s2b,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()
if len(dst.data()) != len(packet):
print("Error: not enough data:", len(dst.data()), len(packet))
ntotal=len(packet)
nwrong = sum(abs(packet-numpy.array(dst.data())));
return (ntotal,nwrong,abs(packet-numpy.array(dst.data())))
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
# alternatively you can specify the fsm from its generator matrix
#f=trellis.fsm(1,2,[5,7])
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_b=0 # total number of transmitted bits
terr_b=0 # total number of bits in error
terr_p=0 # total number of packets in error
for i in range(rep):
(b,e,pattern)=run_test(f,Kb,bitspersymbol,K,dimensionality,constellation,N0,-(666+i)) # run experiment with different seed to get different noise realizations
tot_b=tot_b+b
terr_b=terr_b+e
terr_p=terr_p+(e!=0)
if ((i+1)%100==0) : # display progress
print(i+1,terr_p, '%.2e' % ((1.0*terr_p) / (i+1)),tot_b,terr_b, '%.2e' % ((1.0*terr_b) / tot_b))
if e!=0:
print("rep=",i, e)
for k in range(Kb):
if pattern[k]!=0:
print(k)
# estimate of the bit error rate
print(rep,terr_p, '%.2e' % ((1.0*terr_p) / (i+1)),tot_b,terr_b, '%.2e' % ((1.0*terr_b) / tot_b))
if __name__ == '__main__':
main()
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