#!/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