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#!/usr/bin/env python
#
# Copyright 2005, 2006 Free Software Foundation, Inc.
#
# This file is part of GNU Radio
#
# GNU Radio is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
#
# GNU Radio is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with GNU Radio; see the file COPYING. If not, write to
# the Free Software Foundation, Inc., 51 Franklin Street,
# Boston, MA 02110-1301, USA.
#
from gnuradio import gr, gru, modulation_utils
from gnuradio import usrp
from gnuradio import eng_notation
from gnuradio.eng_option import eng_option
from optparse import OptionParser
import random, time, struct, sys, math, os
# from current dir
from transmit_path import transmit_path
from receive_path import receive_path
import ofdm
class awgn_channel(gr.hier_block):
def __init__(self, fg, sample_rate, noise_voltage, frequency_offset):
self.input = gr.add_const_cc(0)
self.noise_adder = gr.add_cc()
self.noise = gr.noise_source_c(gr.GR_GAUSSIAN,noise_voltage)
self.offset = gr.sig_source_c(1, gr.GR_SIN_WAVE, frequency_offset, 1.0, 0.0)
self.mixer_offset = gr.multiply_cc()
fg.connect(self.input, (self.mixer_offset,0))
fg.connect(self.offset,(self.mixer_offset,1))
fg.connect(self.mixer_offset, (self.noise_adder,1))
fg.connect(self.noise, (self.noise_adder,0))
gr.hier_block.__init__(self, fg, self.input, self.noise_adder)
class multipath_channel(gr.hier_block):
def __init__(self, fg):
self.taps = [1.0, .2, 0.0, .1, .08, -.4, .12, -.2, 0, 0, 0, .3]
self.chan = gr.fir_filter_ccc(1, self.taps)
gr.hier_block.__init__(self, fg, self.chan, self.chan)
class my_graph(gr.flow_graph):
def __init__(self, callback, options):
gr.flow_graph.__init__(self)
channel_on = True
SNR = 10.0**(options.snr/10.0)
frequency_offset = options.frequency_offset / options.fft_length
power_in_signal = options.occupied_tones
noise_power_in_channel = power_in_signal/SNR
noise_power_required = noise_power_in_channel * options.fft_length / options.occupied_tones
noise_voltage = math.sqrt(noise_power_required)
self.txpath = transmit_path(self, options)
self.throttle = gr.throttle(gr.sizeof_gr_complex, options.sample_rate)
self.rxpath = receive_path(self, callback, options)
if channel_on:
self.channel = awgn_channel(self, options.sample_rate, noise_voltage, frequency_offset)
self.multipath = multipath_channel(self)
if options.discontinuous:
z = 20000*[0,]
self.zeros = gr.vector_source_c(z, True)
packet_size = 15*((4+8+4+1500+4) * 8)
self.mux = gr.stream_mux(gr.sizeof_gr_complex, [packet_size-0, int(10e5)])
# Connect components
self.connect(self.txpath, (self.mux,0))
self.connect(self.zeros, (self.mux,1))
self.connect(self.mux, self.throttle, self.channel, self.rxpath)
self.connect(self.mux, gr.file_sink(gr.sizeof_gr_complex, "tx_ofdm.dat"))
else:
#self.connect(self.txpath, self.throttle, self.multipath, self.channel)
self.connect(self.txpath, self.throttle, self.channel)
self.connect(self.channel, self.rxpath)
self.connect(self.txpath, gr.file_sink(gr.sizeof_gr_complex, "tx_ofdm.dat"))
else:
self.connect(self.txpath, self.throttle, self.rxpath)
self.connect(self.txpath, gr.file_sink(gr.sizeof_gr_complex, "tx"))
self.connect(self.rxpath.ofdm_demod.ofdm_rx, gr.file_sink(options.fft_length*gr.sizeof_gr_complex, "rx"))
# /////////////////////////////////////////////////////////////////////////////
# main
# /////////////////////////////////////////////////////////////////////////////
def main():
global n_rcvd, n_right
n_rcvd = 0
n_right = 0
def send_pkt(payload='', eof=False):
return fg.txpath.send_pkt(payload, eof)
def rx_callback(ok, payload):
global n_rcvd, n_right
n_rcvd += 1
(pktno,) = struct.unpack('!H', payload[0:2])
if ok:
n_right += 1
print "ok: %r \t pktno: %d \t n_rcvd: %d \t n_right: %d" % (ok, pktno, n_rcvd, n_right)
parser = OptionParser(option_class=eng_option, conflict_handler="resolve")
expert_grp = parser.add_option_group("Expert")
parser.add_option("-s", "--size", type="eng_float", default=1450,
help="set packet size [default=%default]")
parser.add_option("-M", "--megabytes", type="eng_float", default=1.0,
help="set megabytes to transmit [default=%default]")
parser.add_option("-r", "--sample-rate", type="eng_float", default=1e5,
help="set sample rate to RATE (%default)")
parser.add_option("", "--snr", type="eng_float", default=30,
help="set the SNR of the channel in dB [default=%default]")
parser.add_option("", "--frequency-offset", type="eng_float", default=0,
help="set frequency offset introduced by channel [default=%default]")
parser.add_option("","--discontinuous", action="store_true", default=False,
help="enable discontinous transmission (bursts of 5 packets)")
transmit_path.add_options(parser, expert_grp)
receive_path.add_options(parser, expert_grp)
ofdm.ofdm_mod.add_options(parser, expert_grp)
ofdm.ofdm_demod.add_options(parser, expert_grp)
(options, args) = parser.parse_args ()
if(options.mtu < options.size):
sys.stderr.write("MTU (%.0f) must be larger than the packet size (%.0f)\n"
% (options.mtu, options.size))
sys.exit(1)
# build the graph
fg = my_graph(rx_callback, options)
r = gr.enable_realtime_scheduling()
# if r != gr.RT_OK:
# print "Warning: failed to enable realtime scheduling"
fg.start() # start flow graph
# generate and send packets
nbytes = int(1e6 * options.megabytes)
n = 0
pktno = 0
pkt_size = int(options.size)
while n < nbytes:
r = ''.join([chr(random.randint(0,255)) for i in range(pkt_size-2)])
#pkt_contents = struct.pack('!H', pktno) + (pkt_size - 2) * chr(pktno & 0xff)
pkt_contents = struct.pack('!H', pktno) + r
send_pkt(pkt_contents)
n += pkt_size
#sys.stderr.write('.')
#if options.discontinuous and pktno % 5 == 4:
# time.sleep(1)
pktno += 1
send_pkt(eof=True)
fg.wait() # wait for it to finish
if __name__ == '__main__':
try:
main()
except KeyboardInterrupt:
pass
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