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#!/usr/bin/env python
from gnuradio import gr, blks
from gnuradio.eng_option import eng_option
from optparse import OptionParser
import random
import struct
from mpsk_pkt import *
import cmath
class my_graph(gr.flow_graph):
def __init__(self, rx_callback, spb, excess_bw, SNR, freq_error, arity):
gr.flow_graph.__init__(self)
fg = self
# Tuning Parameters
gain_mu = 0.05/spb
# transmitter
self.packet_transmitter = \
mpsk_mod_pkts(fg, spb=spb, excess_bw=excess_bw, diff=True, arity=arity)
# ----------------------------------------------------------------
# Channel model
# ----------------------------------------------------------------
awgn = gr.noise_source_c(gr.GR_GAUSSIAN, pow(10.0,-SNR/20.0))
add = gr.add_cc() # add some noise
fg.connect(awgn, (add,1))
radians = 17*pi/180
phase_rotate = gr.multiply_const_cc(cmath.exp(radians * 1j))
# ----------------------------------------------------------------
# channel filter
rx_filt_taps = gr.firdes.low_pass(1,spb,0.8,0.1,gr.firdes.WIN_HANN)
#rx_filt_taps = (1,)
rx_filt = gr.fir_filter_ccf(1,rx_filt_taps)
# receiver
self.packet_receiver = \
mpsk_demod_pkts(fg, callback=rx_callback,
excess_bw=excess_bw, arity=arity, diff=True,
costas_alpha=.005, gain_mu=gain_mu, spb=spb)
fg.connect (self.packet_transmitter, (add,0))
fg.connect(add, phase_rotate, rx_filt, self.packet_receiver)
class stats(object):
def __init__(self):
self.npkts = 0
self.nright = 0
def main():
st = stats()
def send_pkt(payload='', eof=False):
fg.packet_transmitter.send_pkt(payload, eof)
def rx_callback(ok, payload):
st.npkts += 1
if ok:
st.nright += 1
if len(payload) <= 16:
print "ok = %5r payload = '%s' %d/%d" % (ok, payload, st.nright, st.npkts)
else:
(pktno,) = struct.unpack('!H', payload[0:2])
print "ok = %5r pktno = %4d len(payload) = %4d %d/%d" % (ok, pktno, len(payload),
st.nright, st.npkts)
parser = OptionParser (option_class=eng_option)
parser.add_option("-M", "--megabytes", type="eng_float", default=1,
help="set megabytes to transmit [default=%default]")
parser.add_option("-s", "--size", type="eng_float", default=1500,
help="set packet size [default=%default]")
parser.add_option("","--spb", type=int, default=4,
help="set samples per baud to SPB [default=%default]")
parser.add_option("", "--excess-bw", type="eng_float", default=0.4,
help="set excess bandwidth for RRC filter [default=%default]")
parser.add_option("", "--snr", type="eng_float", default=40,
help="set SNR in dB for simulation [default=%default]")
parser.add_option("", "--m-arity", type=int, default=4,
help="PSK arity [default=%default]")
parser.add_option("", "--freq-error", type="eng_float", default=0,
help="set frequency error for simulation [default=%default]")
(options, args) = parser.parse_args ()
if len(args) != 0:
parser.print_help()
sys.exit(1)
pkt_size = int(options.size)
fg = my_graph(rx_callback, options.spb, options.excess_bw, options.snr,
options.freq_error, options.m_arity)
fg.start()
nbytes = int(1e6 * options.megabytes)
n = 0
pktno = 0
send_pkt('Hello World')
# generate and send packets
while n < nbytes:
send_pkt(struct.pack('!H', pktno) + (pkt_size - 2) * chr(pktno & 0xff))
n += pkt_size
pktno += 1
send_pkt('Goodbye World')
send_pkt(eof=True) # tell modulator we're not sending any more pkts
fg.wait()
if __name__ == '__main__':
try:
main()
except KeyboardInterrupt:
pass
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