merged -r5966:6112 on trondeau/ofdm_mod. Allows for generic constellations (supports bpsk, qpsk, 8psk, qam16, qam64, and qam256 currently), fixes some bugs in the correlation and altered default parameters for over-the-air operation. This merge fixes ticket:156 and ticket:157.

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@6113 221aa14e-8319-0410-a670-987f0aec2ac5

6 files changed, 451 insertions, 14 deletions

diff --git a/gnuradio-examples/python/ofdm/benchmark_ofdm.py b/gnuradio-examples/python/ofdm/benchmark_ofdm.py
index 778025405..690c57d60 100755
--- a/gnuradio-examples/python/ofdm/benchmark_ofdm.py
+++ b/gnuradio-examples/python/ofdm/benchmark_ofdm.py
@@ -36,14 +36,15 @@ class my_graph(gr.flow_graph):
     def __init__(self, callback, options):
         gr.flow_graph.__init__(self)
 
-        if options.channel_on:
+        if not options.channel_off:
             SNR = 10.0**(options.snr/10.0)
-            power_in_signal = 1.0
+            power_in_signal = abs(options.tx_amplitude)**2.0
             noise_power_in_channel = power_in_signal/SNR
             noise_voltage = math.sqrt(noise_power_in_channel/2.0)
             print "Noise voltage: ", noise_voltage
 
             frequency_offset = options.frequency_offset / options.fft_length
+            print "Frequency offset: ", frequency_offset
 
             if options.multipath_on:
                 taps = [1.0, .2, 0.0, .1, .08, -.4, .12, -.2, 0, 0, 0, .3]
@@ -70,7 +71,8 @@ class my_graph(gr.flow_graph):
 
         self.mux = gr.stream_mux(gr.sizeof_gr_complex, stream_size)
         self.throttle = gr.throttle(gr.sizeof_gr_complex, options.sample_rate)
-        self.channel = blks.channel_model(self, noise_voltage, frequency_offset, options.clockrate_ratio, taps)
+        self.channel = blks.channel_model(self, noise_voltage, frequency_offset,
+                                          options.clockrate_ratio, taps)
         self.rxpath = receive_path(self, callback, options)
                 
         self.connect(self.zeros, (self.mux,0))
@@ -116,7 +118,7 @@ def main():
                 
     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,
+    parser.add_option("-s", "--size", type="eng_float", default=400,
                       help="set packet size [default=%default]")
     parser.add_option("-M", "--megabytes", type="eng_float", default=1.0,
                       help="set megabytes to transmit [default=%default]")
@@ -130,8 +132,8 @@ def main():
                       help="set clock rate ratio (sample rate difference) between two systems [default=%default]")
     parser.add_option("","--discontinuous", type="int", default=0,
                       help="enable discontinous transmission, burst of N packets [Default is continuous]")
-    parser.add_option("","--channel-on", action="store_true", default=True,
-                      help="Enables AWGN, freq offset")
+    parser.add_option("","--channel-off", action="store_true", default=False,
+                      help="Turns AWGN, freq offset channel off")
     parser.add_option("","--multipath-on", action="store_true", default=False,
                       help="enable multipath")
 
diff --git a/gnuradio-examples/python/ofdm/benchmark_ofdm_rx.py b/gnuradio-examples/python/ofdm/benchmark_ofdm_rx.py
index 3e033af4e..a8c20d390 100755
--- a/gnuradio-examples/python/ofdm/benchmark_ofdm_rx.py
+++ b/gnuradio-examples/python/ofdm/benchmark_ofdm_rx.py
@@ -128,7 +128,7 @@ class usrp_graph(gr.flow_graph):
 
         expert.add_option("", "--rx-freq", type="eng_float", default=None,
                           help="set Rx frequency to FREQ [default=%default]", metavar="FREQ")
-        expert.add_option("-d", "--decim", type="intx", default=32,
+        expert.add_option("-d", "--decim", type="intx", default=128,
                           help="set fpga decimation rate to DECIM [default=%default]")
         expert.add_option("", "--snr", type="eng_float", default=30,
                           help="set the SNR of the channel in dB [default=%default]")
diff --git a/gnuradio-examples/python/ofdm/benchmark_ofdm_tx.py b/gnuradio-examples/python/ofdm/benchmark_ofdm_tx.py
index ac7bc0bc7..a9d1e00e6 100755
--- a/gnuradio-examples/python/ofdm/benchmark_ofdm_tx.py
+++ b/gnuradio-examples/python/ofdm/benchmark_ofdm_tx.py
@@ -131,7 +131,7 @@ class usrp_graph(gr.flow_graph):
 
         expert.add_option("", "--tx-freq", type="eng_float", default=None,
                           help="set transmit frequency to FREQ [default=%default]", metavar="FREQ")
-        expert.add_option("-i", "--interp", type="intx", default=64,
+        expert.add_option("-i", "--interp", type="intx", default=256,
                           help="set fpga interpolation rate to INTERP [default=%default]")
     # Make a static method to call before instantiation
     add_options = staticmethod(add_options)
@@ -171,7 +171,7 @@ def main():
 
     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,
+    parser.add_option("-s", "--size", type="eng_float", default=400,
                       help="set packet size [default=%default]")
     parser.add_option("-M", "--megabytes", type="eng_float", default=1.0,
                       help="set megabytes to transmit [default=%default]")
diff --git a/gnuradio-examples/python/ofdm/receive_path.py b/gnuradio-examples/python/ofdm/receive_path.py
index 93e1e59a3..2ebaad883 100644
--- a/gnuradio-examples/python/ofdm/receive_path.py
+++ b/gnuradio-examples/python/ofdm/receive_path.py
@@ -47,10 +47,10 @@ class receive_path(gr.hier_block):
                      blks.ofdm_demod(fg, options, callback=self._rx_callback)
 
         # Carrier Sensing Blocks
-        #alpha = 0.001
-        #thresh = 30   # in dB, will have to adjust
-        #self.probe = gr.probe_avg_mag_sqrd_c(thresh,alpha)
-        #fg.connect(self.chan_filt, self.probe)
+        alpha = 0.001
+        thresh = 30   # in dB, will have to adjust
+        self.probe = gr.probe_avg_mag_sqrd_c(thresh,alpha)
+        fg.connect(self.ofdm_rx.ofdm_recv.chan_filt, self.probe)
 
         # Display some information about the setup
         if self._verbose:
diff --git a/gnuradio-examples/python/ofdm/transmit_path.py b/gnuradio-examples/python/ofdm/transmit_path.py
index 080aee923..f15845b00 100644
--- a/gnuradio-examples/python/ofdm/transmit_path.py
+++ b/gnuradio-examples/python/ofdm/transmit_path.py
@@ -73,7 +73,7 @@ class transmit_path(gr.hier_block):
         """
         Adds transmitter-specific options to the Options Parser
         """
-        normal.add_option("", "--tx-amplitude", type="eng_float", default=1, metavar="AMPL",
+        normal.add_option("", "--tx-amplitude", type="eng_float", default=200, metavar="AMPL",
                           help="set transmitter digital amplitude: 0 <= AMPL < 32768 [default=%default]")
         normal.add_option("-v", "--verbose", action="store_true", default=False)
         expert.add_option("", "--log", action="store_true", default=False,
diff --git a/gnuradio-examples/python/ofdm/tunnel.py b/gnuradio-examples/python/ofdm/tunnel.py
new file mode 100755
index 000000000..5babd3282
--- /dev/null
+++ b/gnuradio-examples/python/ofdm/tunnel.py
@@ -0,0 +1,435 @@
+#!/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.
+# 
+
+
+# /////////////////////////////////////////////////////////////////////////////
+#
+#    This code sets up up a virtual ethernet interface (typically gr0),
+#    and relays packets between the interface and the GNU Radio PHY+MAC
+#
+#    What this means in plain language, is that if you've got a couple
+#    of USRPs on different machines, and if you run this code on those
+#    machines, you can talk between them using normal TCP/IP networking.
+#
+# /////////////////////////////////////////////////////////////////////////////
+
+
+from gnuradio import gr, gru, blks
+from gnuradio import usrp
+from gnuradio import eng_notation
+from gnuradio.eng_option import eng_option
+from optparse import OptionParser
+
+import random
+import time
+import struct
+import sys
+import os
+
+# from current dir
+from transmit_path import transmit_path
+from receive_path import receive_path
+import fusb_options
+
+#print os.getpid()
+#raw_input('Attach and press enter')
+
+
+# /////////////////////////////////////////////////////////////////////////////
+#
+#   Use the Universal TUN/TAP device driver to move packets to/from kernel
+#
+#   See /usr/src/linux/Documentation/networking/tuntap.txt
+#
+# /////////////////////////////////////////////////////////////////////////////
+
+# Linux specific...
+# TUNSETIFF ifr flags from <linux/tun_if.h>
+
+IFF_TUN		= 0x0001   # tunnel IP packets
+IFF_TAP		= 0x0002   # tunnel ethernet frames
+IFF_NO_PI	= 0x1000   # don't pass extra packet info
+IFF_ONE_QUEUE	= 0x2000   # beats me ;)
+
+def open_tun_interface(tun_device_filename):
+    from fcntl import ioctl
+    
+    mode = IFF_TAP | IFF_NO_PI
+    TUNSETIFF = 0x400454ca
+
+    tun = os.open(tun_device_filename, os.O_RDWR)
+    ifs = ioctl(tun, TUNSETIFF, struct.pack("16sH", "gr%d", mode))
+    ifname = ifs[:16].strip("\x00")
+    return (tun, ifname)
+    
+
+# /////////////////////////////////////////////////////////////////////////////
+#                             the flow graph
+# /////////////////////////////////////////////////////////////////////////////
+
+class usrp_graph(gr.flow_graph):
+    def __init__(self, callback, options):
+        gr.flow_graph.__init__(self)
+
+        self._tx_freq            = options.tx_freq         # tranmitter's center frequency
+        self._tx_subdev_spec     = options.tx_subdev_spec  # daughterboard to use
+        self._interp             = options.interp          # interpolating rate for the USRP (prelim)
+        self._rx_freq            = options.rx_freq         # receiver's center frequency
+        self._rx_gain            = options.rx_gain         # receiver's gain
+        self._rx_subdev_spec     = options.rx_subdev_spec  # daughterboard to use
+        self._decim              = options.decim           # Decimating rate for the USRP (prelim)
+        self._fusb_block_size    = options.fusb_block_size # usb info for USRP
+        self._fusb_nblocks       = options.fusb_nblocks    # usb info for USRP
+
+        if self._tx_freq is None:
+            sys.stderr.write("-f FREQ or --freq FREQ or --tx-freq FREQ must be specified\n")
+            raise SystemExit
+
+        if self._rx_freq is None:
+            sys.stderr.write("-f FREQ or --freq FREQ or --rx-freq FREQ must be specified\n")
+            raise SystemExit
+
+        # Set up USRP sink and source
+        self._setup_usrp_sink()
+        self._setup_usrp_source()
+
+        # Set center frequency of USRP
+        ok = self.set_freq(self._tx_freq)
+        if not ok:
+            print "Failed to set Tx frequency to %s" % (eng_notation.num_to_str(self._tx_freq),)
+            raise ValueError
+
+        # copy the final answers back into options for use by modulator
+        #options.bitrate = self._bitrate
+
+        self.txpath = transmit_path(self, options)
+        self.rxpath = receive_path(self, callback, options)
+
+        self.connect(self.txpath, self.u_snk)
+        self.connect(self.u_src, self.rxpath)
+
+    def carrier_sensed(self):
+        """
+        Return True if the receive path thinks there's carrier
+        """
+        return self.rxpath.carrier_sensed()
+
+    def _setup_usrp_sink(self):
+        """
+        Creates a USRP sink, determines the settings for best bitrate,
+        and attaches to the transmitter's subdevice.
+        """
+        self.u_snk = usrp.sink_c(fusb_block_size=self._fusb_block_size,
+                                 fusb_nblocks=self._fusb_nblocks)
+
+        self.u_snk.set_interp_rate(self._interp)
+
+        # determine the daughterboard subdevice we're using
+        if self._tx_subdev_spec is None:
+            self._tx_subdev_spec = usrp.pick_tx_subdevice(self.u_snk)
+        self.u_snk.set_mux(usrp.determine_tx_mux_value(self.u_snk, self._tx_subdev_spec))
+        self.subdev = usrp.selected_subdev(self.u_snk, self._tx_subdev_spec)
+
+        # Set the USRP for maximum transmit gain
+        # (Note that on the RFX cards this is a nop.)
+        self.set_gain(self.subdev.gain_range()[1])
+
+        # enable Auto Transmit/Receive switching
+        self.set_auto_tr(True)
+
+    def _setup_usrp_source(self):
+        self.u_src = usrp.source_c (fusb_block_size=self._fusb_block_size,
+                                fusb_nblocks=self._fusb_nblocks)
+        adc_rate = self.u_src.adc_rate()
+
+        self.u_src.set_decim_rate(self._decim)
+
+        # determine the daughterboard subdevice we're using
+        if self._rx_subdev_spec is None:
+            self._rx_subdev_spec = usrp.pick_rx_subdevice(self.u_src)
+        self.subdev = usrp.selected_subdev(self.u_src, self._rx_subdev_spec)
+
+        self.u_src.set_mux(usrp.determine_rx_mux_value(self.u_src, self._rx_subdev_spec))
+
+    def set_freq(self, target_freq):
+        """
+        Set the center frequency we're interested in.
+
+        @param target_freq: frequency in Hz
+        @rypte: bool
+
+        Tuning is a two step process.  First we ask the front-end to
+        tune as close to the desired frequency as it can.  Then we use
+        the result of that operation and our target_frequency to
+        determine the value for the digital up converter.
+        """
+        r_snk = self.u_snk.tune(self.subdev._which, self.subdev, target_freq)
+        r_src = self.u_src.tune(self.subdev._which, self.subdev, target_freq)
+        if r_snk and r_src:
+            return True
+
+        return False
+        
+    def set_gain(self, gain):
+        """
+        Sets the analog gain in the USRP
+        """
+        self.gain = gain
+        self.subdev.set_gain(gain)
+
+    def set_auto_tr(self, enable):
+        """
+        Turns on auto transmit/receive of USRP daughterboard (if exits; else ignored)
+        """
+        return self.subdev.set_auto_tr(enable)
+        
+    def interp(self):
+        return self._interp
+
+    def add_options(normal, expert):
+        """
+        Adds usrp-specific options to the Options Parser
+        """
+        add_freq_option(normal)
+        normal.add_option("-T", "--tx-subdev-spec", type="subdev", default=None,
+                          help="select USRP Tx side A or B")
+        normal.add_option("-v", "--verbose", action="store_true", default=False)
+
+        expert.add_option("", "--tx-freq", type="eng_float", default=None,
+                          help="set transmit frequency to FREQ [default=%default]", metavar="FREQ")
+        expert.add_option("-i", "--interp", type="intx", default=256,
+                          help="set fpga interpolation rate to INTERP [default=%default]")
+        normal.add_option("-R", "--rx-subdev-spec", type="subdev", default=None,
+                          help="select USRP Rx side A or B")
+        normal.add_option("", "--rx-gain", type="eng_float", default=None, metavar="GAIN",
+                          help="set receiver gain in dB [default=midpoint].  See also --show-rx-gain-range")
+        normal.add_option("", "--show-rx-gain-range", action="store_true", default=False, 
+                          help="print min and max Rx gain available on selected daughterboard")
+        normal.add_option("-v", "--verbose", action="store_true", default=False)
+
+        expert.add_option("", "--rx-freq", type="eng_float", default=None,
+                          help="set Rx frequency to FREQ [default=%default]", metavar="FREQ")
+        expert.add_option("-d", "--decim", type="intx", default=128,
+                          help="set fpga decimation rate to DECIM [default=%default]")
+        expert.add_option("", "--snr", type="eng_float", default=30,
+                          help="set the SNR of the channel in dB [default=%default]")
+   
+    # Make a static method to call before instantiation
+    add_options = staticmethod(add_options)
+
+    def _print_verbage(self):
+        """
+        Prints information about the transmit path
+        """
+        print "Using TX d'board %s"    % (self.subdev.side_and_name(),)
+        print "modulation:      %s"    % (self._modulator_class.__name__)
+        print "interp:          %3d"   % (self._interp)
+        print "Tx Frequency:    %s"    % (eng_notation.num_to_str(self._tx_freq))
+        
+def add_freq_option(parser):
+    """
+    Hackery that has the -f / --freq option set both tx_freq and rx_freq
+    """
+    def freq_callback(option, opt_str, value, parser):
+        parser.values.rx_freq = value
+        parser.values.tx_freq = value
+
+    if not parser.has_option('--freq'):
+        parser.add_option('-f', '--freq', type="eng_float",
+                          action="callback", callback=freq_callback,
+                          help="set Tx and/or Rx frequency to FREQ [default=%default]",
+                          metavar="FREQ")
+
+
+# /////////////////////////////////////////////////////////////////////////////
+#                           Carrier Sense MAC
+# /////////////////////////////////////////////////////////////////////////////
+
+class cs_mac(object):
+    """
+    Prototype carrier sense MAC
+
+    Reads packets from the TUN/TAP interface, and sends them to the PHY.
+    Receives packets from the PHY via phy_rx_callback, and sends them
+    into the TUN/TAP interface.
+
+    Of course, we're not restricted to getting packets via TUN/TAP, this
+    is just an example.
+    """
+    def __init__(self, tun_fd, verbose=False):
+        self.tun_fd = tun_fd       # file descriptor for TUN/TAP interface
+        self.verbose = verbose
+        self.fg = None             # flow graph (access to PHY)
+
+    def set_flow_graph(self, fg):
+        self.fg = fg
+
+    def phy_rx_callback(self, ok, payload):
+        """
+        Invoked by thread associated with PHY to pass received packet up.
+
+        @param ok: bool indicating whether payload CRC was OK
+        @param payload: contents of the packet (string)
+        """
+        if self.verbose:
+            print "Rx: ok = %r  len(payload) = %4d" % (ok, len(payload))
+        if ok:
+            os.write(self.tun_fd, payload)
+
+    def main_loop(self):
+        """
+        Main loop for MAC.
+        Only returns if we get an error reading from TUN.
+
+        FIXME: may want to check for EINTR and EAGAIN and reissue read
+        """
+        min_delay = 0.001               # seconds
+
+        while 1:
+            payload = os.read(self.tun_fd, 10*1024)
+            if not payload:
+                self.fg.send_pkt(eof=True)
+                break
+
+            if self.verbose:
+                print "Tx: len(payload) = %4d" % (len(payload),)
+
+            delay = min_delay
+            while self.fg.carrier_sensed():
+                sys.stderr.write('B')
+                time.sleep(delay)
+                if delay < 0.050:
+                    delay = delay * 2       # exponential back-off
+
+            self.fg.send_pkt(payload)
+
+
+# /////////////////////////////////////////////////////////////////////////////
+#                                   main
+# /////////////////////////////////////////////////////////////////////////////
+
+def main():
+
+    parser = OptionParser (option_class=eng_option, conflict_handler="resolve")
+    expert_grp = parser.add_option_group("Expert")
+
+    parser.add_option("-m", "--modulation", type="choice", choices=['bpsk', 'qpsk'],
+                      default='bpsk',
+                      help="Select modulation from: bpsk, qpsk [default=%%default]")
+    
+    parser.add_option("-v","--verbose", action="store_true", default=False)
+    expert_grp.add_option("-c", "--carrier-threshold", type="eng_float", default=30,
+                          help="set carrier detect threshold (dB) [default=%default]")
+    expert_grp.add_option("","--tun-device-filename", default="/dev/net/tun",
+                          help="path to tun device file [default=%default]")
+
+    usrp_graph.add_options(parser, expert_grp)
+    transmit_path.add_options(parser, expert_grp)
+    receive_path.add_options(parser, expert_grp)
+    blks.ofdm_mod.add_options(parser, expert_grp)
+    blks.ofdm_demod.add_options(parser, expert_grp)
+
+    fusb_options.add_options(expert_grp)
+
+    (options, args) = parser.parse_args ()
+    if len(args) != 0:
+        parser.print_help(sys.stderr)
+        sys.exit(1)
+
+    if options.rx_freq is None or options.tx_freq is None:
+        sys.stderr.write("You must specify -f FREQ or --freq FREQ\n")
+        parser.print_help(sys.stderr)
+        sys.exit(1)
+
+    # open the TUN/TAP interface
+    (tun_fd, tun_ifname) = open_tun_interface(options.tun_device_filename)
+
+    # Attempt to enable realtime scheduling
+    r = gr.enable_realtime_scheduling()
+    if r == gr.RT_OK:
+        realtime = True
+    else:
+        realtime = False
+        print "Note: failed to enable realtime scheduling"
+
+
+    # If the user hasn't set the fusb_* parameters on the command line,
+    # pick some values that will reduce latency.
+
+    if options.fusb_block_size == 0 and options.fusb_nblocks == 0:
+        if realtime:                        # be more aggressive
+            options.fusb_block_size = gr.prefs().get_long('fusb', 'rt_block_size', 1024)
+            options.fusb_nblocks    = gr.prefs().get_long('fusb', 'rt_nblocks', 16)
+        else:
+            options.fusb_block_size = gr.prefs().get_long('fusb', 'block_size', 4096)
+            options.fusb_nblocks    = gr.prefs().get_long('fusb', 'nblocks', 16)
+    
+    #print "fusb_block_size =", options.fusb_block_size
+    #print "fusb_nblocks    =", options.fusb_nblocks
+
+    # instantiate the MAC
+    mac = cs_mac(tun_fd, verbose=True)
+
+
+    # build the graph (PHY)
+    fg = usrp_graph(mac.phy_rx_callback, options)
+
+    mac.set_flow_graph(fg)    # give the MAC a handle for the PHY
+
+    #if fg.txpath.bitrate() != fg.rxpath.bitrate():
+    #    print "WARNING: Transmit bitrate = %sb/sec, Receive bitrate = %sb/sec" % (
+    #        eng_notation.num_to_str(fg.txpath.bitrate()),
+    #        eng_notation.num_to_str(fg.rxpath.bitrate()))
+             
+    print "modulation:     %s"   % (options.modulation,)
+    print "freq:           %s"      % (eng_notation.num_to_str(options.tx_freq))
+    #print "bitrate:        %sb/sec" % (eng_notation.num_to_str(fg.txpath.bitrate()),)
+    #print "samples/symbol: %3d" % (fg.txpath.samples_per_symbol(),)
+    #print "interp:         %3d" % (fg.txpath.interp(),)
+    #print "decim:          %3d" % (fg.rxpath.decim(),)
+
+    fg.rxpath.set_carrier_threshold(options.carrier_threshold)
+    print "Carrier sense threshold:", options.carrier_threshold, "dB"
+    
+    print
+    print "Allocated virtual ethernet interface: %s" % (tun_ifname,)
+    print "You must now use ifconfig to set its IP address. E.g.,"
+    print
+    print "  $ sudo ifconfig %s 192.168.200.1" % (tun_ifname,)
+    print
+    print "Be sure to use a different address in the same subnet for each machine."
+    print
+
+
+    fg.start()    # Start executing the flow graph (runs in separate threads)
+
+    mac.main_loop()    # don't expect this to return...
+
+    fg.stop()     # but if it does, tell flow graph to stop.
+    fg.wait()     # wait for it to finish
+                
+
+if __name__ == '__main__':
+    try:
+        main()
+    except KeyboardInterrupt:
+        pass