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#!/usr/bin/env python
#
# Copyright 2006,2007,2008 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 3, 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.
#
import math
from gnuradio import gr
import digital_swig
import ofdm_packet_utils
from ofdm_receiver import ofdm_receiver
import gnuradio.gr.gr_threading as _threading
import psk, qam
# /////////////////////////////////////////////////////////////////////////////
# mod/demod with packets as i/o
# /////////////////////////////////////////////////////////////////////////////
class ofdm_mod(gr.hier_block2):
"""
Modulates an OFDM stream. Based on the options fft_length, occupied_tones, and
cp_length, this block creates OFDM symbols using a specified modulation option.
Send packets by calling send_pkt
"""
def __init__(self, options, msgq_limit=2, pad_for_usrp=True):
"""
Hierarchical block for sending packets
Packets to be sent are enqueued by calling send_pkt.
The output is the complex modulated signal at baseband.
@param options: pass modulation options from higher layers (fft length, occupied tones, etc.)
@param msgq_limit: maximum number of messages in message queue
@type msgq_limit: int
@param pad_for_usrp: If true, packets are padded such that they end up a multiple of 128 samples
"""
gr.hier_block2.__init__(self, "ofdm_mod",
gr.io_signature(0, 0, 0), # Input signature
gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
self._pad_for_usrp = pad_for_usrp
self._modulation = options.modulation
self._fft_length = options.fft_length
self._occupied_tones = options.occupied_tones
self._cp_length = options.cp_length
win = [] #[1 for i in range(self._fft_length)]
# Use freq domain to get doubled-up known symbol for correlation in time domain
zeros_on_left = int(math.ceil((self._fft_length - self._occupied_tones)/2.0))
ksfreq = known_symbols_4512_3[0:self._occupied_tones]
for i in range(len(ksfreq)):
if((zeros_on_left + i) & 1):
ksfreq[i] = 0
# hard-coded known symbols
preambles = (ksfreq,)
padded_preambles = list()
for pre in preambles:
padded = self._fft_length*[0,]
padded[zeros_on_left : zeros_on_left + self._occupied_tones] = pre
padded_preambles.append(padded)
symbol_length = options.fft_length + options.cp_length
mods = {"bpsk": 2, "qpsk": 4, "8psk": 8, "qam8": 8, "qam16": 16, "qam64": 64, "qam256": 256}
arity = mods[self._modulation]
rot = 1
if self._modulation == "qpsk":
rot = (0.707+0.707j)
if(self._modulation.find("psk") >= 0):
rotated_const = map(lambda pt: pt * rot, psk.gray_constellation[arity])
elif(self._modulation.find("qam") >= 0):
rotated_const = map(lambda pt: pt * rot, qam.constellation[arity])
#print rotated_const
self._pkt_input = digital_swig.ofdm_mapper_bcv(rotated_const,
msgq_limit,
options.occupied_tones,
options.fft_length)
self.preambles = digital_swig.ofdm_insert_preamble(self._fft_length,
padded_preambles)
self.ifft = gr.fft_vcc(self._fft_length, False, win, True)
self.cp_adder = digital_swig.ofdm_cyclic_prefixer(self._fft_length,
symbol_length)
self.scale = gr.multiply_const_cc(1.0 / math.sqrt(self._fft_length))
self.connect((self._pkt_input, 0), (self.preambles, 0))
self.connect((self._pkt_input, 1), (self.preambles, 1))
self.connect(self.preambles, self.ifft, self.cp_adder, self.scale, self)
if options.verbose:
self._print_verbage()
if options.log:
self.connect(self._pkt_input, gr.file_sink(gr.sizeof_gr_complex*options.fft_length,
"ofdm_mapper_c.dat"))
self.connect(self.preambles, gr.file_sink(gr.sizeof_gr_complex*options.fft_length,
"ofdm_preambles.dat"))
self.connect(self.ifft, gr.file_sink(gr.sizeof_gr_complex*options.fft_length,
"ofdm_ifft_c.dat"))
self.connect(self.cp_adder, gr.file_sink(gr.sizeof_gr_complex,
"ofdm_cp_adder_c.dat"))
def send_pkt(self, payload='', eof=False):
"""
Send the payload.
@param payload: data to send
@type payload: string
"""
if eof:
msg = gr.message(1) # tell self._pkt_input we're not sending any more packets
else:
# print "original_payload =", string_to_hex_list(payload)
pkt = ofdm_packet_utils.make_packet(payload, 1, 1,
self._pad_for_usrp,
whitening=True)
#print "pkt =", string_to_hex_list(pkt)
msg = gr.message_from_string(pkt)
self._pkt_input.msgq().insert_tail(msg)
def add_options(normal, expert):
"""
Adds OFDM-specific options to the Options Parser
"""
normal.add_option("-m", "--modulation", type="string", default="bpsk",
help="set modulation type (bpsk, qpsk, 8psk, qam{16,64}) [default=%default]")
expert.add_option("", "--fft-length", type="intx", default=512,
help="set the number of FFT bins [default=%default]")
expert.add_option("", "--occupied-tones", type="intx", default=200,
help="set the number of occupied FFT bins [default=%default]")
expert.add_option("", "--cp-length", type="intx", default=128,
help="set the number of bits in the cyclic prefix [default=%default]")
# Make a static method to call before instantiation
add_options = staticmethod(add_options)
def _print_verbage(self):
"""
Prints information about the OFDM modulator
"""
print "\nOFDM Modulator:"
print "Modulation Type: %s" % (self._modulation)
print "FFT length: %3d" % (self._fft_length)
print "Occupied Tones: %3d" % (self._occupied_tones)
print "CP length: %3d" % (self._cp_length)
class ofdm_demod(gr.hier_block2):
"""
Demodulates a received OFDM stream. Based on the options fft_length, occupied_tones, and
cp_length, this block performs synchronization, FFT, and demodulation of incoming OFDM
symbols and passes packets up the a higher layer.
The input is complex baseband. When packets are demodulated, they are passed to the
app via the callback.
"""
def __init__(self, options, callback=None):
"""
Hierarchical block for demodulating and deframing packets.
The input is the complex modulated signal at baseband.
Demodulated packets are sent to the handler.
@param options: pass modulation options from higher layers (fft length, occupied tones, etc.)
@param callback: function of two args: ok, payload
@type callback: ok: bool; payload: string
"""
gr.hier_block2.__init__(self, "ofdm_demod",
gr.io_signature(1, 1, gr.sizeof_gr_complex), # Input signature
gr.io_signature(1, 1, gr.sizeof_gr_complex)) # Output signature
self._rcvd_pktq = gr.msg_queue() # holds packets from the PHY
self._modulation = options.modulation
self._fft_length = options.fft_length
self._occupied_tones = options.occupied_tones
self._cp_length = options.cp_length
self._snr = options.snr
# Use freq domain to get doubled-up known symbol for correlation in time domain
zeros_on_left = int(math.ceil((self._fft_length - self._occupied_tones)/2.0))
ksfreq = known_symbols_4512_3[0:self._occupied_tones]
for i in range(len(ksfreq)):
if((zeros_on_left + i) & 1):
ksfreq[i] = 0
# hard-coded known symbols
preambles = (ksfreq,)
symbol_length = self._fft_length + self._cp_length
self.ofdm_recv = ofdm_receiver(self._fft_length,
self._cp_length,
self._occupied_tones,
self._snr, preambles,
options.log)
mods = {"bpsk": 2, "qpsk": 4, "8psk": 8, "qam8": 8, "qam16": 16, "qam64": 64, "qam256": 256}
arity = mods[self._modulation]
rot = 1
if self._modulation == "qpsk":
rot = (0.707+0.707j)
if(self._modulation.find("psk") >= 0):
rotated_const = map(lambda pt: pt * rot, psk.gray_constellation[arity])
elif(self._modulation.find("qam") >= 0):
rotated_const = map(lambda pt: pt * rot, qam.constellation[arity])
#print rotated_const
phgain = 0.25
frgain = phgain*phgain / 4.0
self.ofdm_demod = digital_swig.ofdm_frame_sink(rotated_const, range(arity),
self._rcvd_pktq,
self._occupied_tones,
phgain, frgain)
self.connect(self, self.ofdm_recv)
self.connect((self.ofdm_recv, 0), (self.ofdm_demod, 0))
self.connect((self.ofdm_recv, 1), (self.ofdm_demod, 1))
# added output signature to work around bug, though it might not be a bad
# thing to export, anyway
self.connect(self.ofdm_recv.chan_filt, self)
if options.log:
self.connect(self.ofdm_demod,
gr.file_sink(gr.sizeof_gr_complex*self._occupied_tones,
"ofdm_frame_sink_c.dat"))
else:
self.connect(self.ofdm_demod,
gr.null_sink(gr.sizeof_gr_complex*self._occupied_tones))
if options.verbose:
self._print_verbage()
self._watcher = _queue_watcher_thread(self._rcvd_pktq, callback)
def add_options(normal, expert):
"""
Adds OFDM-specific options to the Options Parser
"""
normal.add_option("-m", "--modulation", type="string", default="bpsk",
help="set modulation type (bpsk or qpsk) [default=%default]")
expert.add_option("", "--fft-length", type="intx", default=512,
help="set the number of FFT bins [default=%default]")
expert.add_option("", "--occupied-tones", type="intx", default=200,
help="set the number of occupied FFT bins [default=%default]")
expert.add_option("", "--cp-length", type="intx", default=128,
help="set the number of bits in the cyclic prefix [default=%default]")
expert.add_option("", "--snr", type="float", default=30.0,
help="SNR estimate [default=%default]")
# Make a static method to call before instantiation
add_options = staticmethod(add_options)
def _print_verbage(self):
"""
Prints information about the OFDM demodulator
"""
print "\nOFDM Demodulator:"
print "Modulation Type: %s" % (self._modulation)
print "FFT length: %3d" % (self._fft_length)
print "Occupied Tones: %3d" % (self._occupied_tones)
print "CP length: %3d" % (self._cp_length)
class _queue_watcher_thread(_threading.Thread):
def __init__(self, rcvd_pktq, callback):
_threading.Thread.__init__(self)
self.setDaemon(1)
self.rcvd_pktq = rcvd_pktq
self.callback = callback
self.keep_running = True
self.start()
def run(self):
while self.keep_running:
msg = self.rcvd_pktq.delete_head()
ok, payload = ofdm_packet_utils.unmake_packet(msg.to_string())
if self.callback:
self.callback(ok, payload)
# Generating known symbols with:
# i = [2*random.randint(0,1)-1 for i in range(4512)]
known_symbols_4512_3 = [-1, -1, 1, -1, 1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, -1, 1, -1, -1, -1, 1, -1, -1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, -1, -1, -1, -1, 1, -1, -1, -1, -1, 1, -1, 1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, 1, -1, 1, 1, 1, -1, -1, -1, 1, 1, 1, 1, 1, 1, -1, -1, 1, 1, 1, -1, -1, 1, -1, -1, 1, 1, 1, -1, -1, 1, 1, -1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, 1, -1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, -1, 1, -1, 1, 1, -1, -1, -1, 1, 1, -1, -1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, -1, -1, 1, -1, -1, 1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, -1, -1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, 1, 1, -1, -1, -1, -1, 1, -1, -1, 1, 1, -1, 1, -1, 1, -1, 1, -1, 1, -1, -1, -1, -1, 1, -1, 1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, 1, -1, 1, 1, -1, 1, -1, 1, 1, -1, 1, -1, -1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, -1, -1, -1, 1, -1, -1, 1, 1, 1, -1, 1, -1, 1, 1, -1, -1, -1, -1, 1, -1, 1, -1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, 1, -1, -1, 1, -1, -1, 1, -1, -1, -1, 1, -1, 1, -1, 1, 1, 1, 1, 1, 1, -1, -1, 1, -1, 1, -1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, -1, 1, 1, 1, 1, 1, -1, 1, -1, -1, -1, -1, -1, -1, 1, 1, -1, -1, 1, -1, 1, 1, 1, 1, -1, 1, -1, 1, -1, -1, 1, -1, -1, -1, -1, 1, 1, -1, 1, 1, 1, -1, -1, 1, 1, 1, -1, -1, -1, -1, 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