Merged r4518:5130 from developer branch n4hy/ofdm into trunk, passes distcheck.

Adds incomplete OFDM implementation, further work to be completed in the
features/ofdm branch.


git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@5131 221aa14e-8319-0410-a670-987f0aec2ac5

1 files changed, 161 insertions, 0 deletions

diff --git a/gnuradio-examples/python/ofdm/ofdm.py b/gnuradio-examples/python/ofdm/ofdm.py
new file mode 100644
index 000000000..8b1e616f9
--- /dev/null
+++ b/gnuradio-examples/python/ofdm/ofdm.py
@@ -0,0 +1,161 @@
+#!/usr/bin/env python
+#
+# Copyright 2004,2005,2006 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
+from optparse import OptionParser
+from ofdm_receiver import ofdm_receiver
+
+class ofdm_mod(gr.hier_block):
+    def __init__(self, fg, options):
+        self.fg = fg
+        self._occupied_tones = options.occupied_tones
+        self._fft_length = options.fft_length
+        self._cp_length = options.cp_length
+        self._mtu = options.mtu
+
+        symbol_length = self._fft_length + self._cp_length
+
+        if self._fft_length < self._occupied_tones:
+            sys.stderr.write("occupied tones must be less than FFT length\n")
+            raise SystemExit
+        if self._fft_length < self._cp_length:
+            sys.stderr.write("cyclic prefix length  must be less than FFT length\n")
+            raise SystemExit
+
+        win = [] #[1 for i in range(self._fft_length)]
+
+        # hard-coded known symbol
+        #ks = self._occupied_tones*[1,]
+        ks1 = known_symbols_200_1
+        ks2 = known_symbols_200_2
+        
+        self.ofdm = gr.ofdm_bpsk_mapper(self._mtu, self._occupied_tones, self._fft_length, ks1, ks2)
+        self.ifft = gr.fft_vcc(self._fft_length, False, win, True)
+        self.cp_adder = gr.ofdm_cyclic_prefixer(self._fft_length, symbol_length)
+        
+        if options.verbose:
+            self._print_verbage()
+
+        self.fg.connect(self.ofdm, self.ifft, self.cp_adder)
+        gr.hier_block.__init__(self, self.fg, self.ofdm, self.cp_adder)
+
+    def samples_per_symbol(self):
+        return 2
+
+    def mtu(self):
+        return self._mtu
+
+    def bits_per_symbol(self=None):   # staticmethod that's also callable on an instance
+        return 1
+    bits_per_symbol = staticmethod(bits_per_symbol)      # make it a static method.  RTFM
+
+    def add_options(normal, expert):
+        """
+        Adds OFDM-specific options to the Options Parser
+        """
+        expert.add_option("", "--mtu", type="int", default=1500,
+                          help="set maximum transmit unit [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 "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_block):
+    def __init__(self, fg, options):
+        self.fg = fg
+        self._occupied_tones = options.occupied_tones
+        self._fft_length = options.fft_length
+        self._cp_length = options.cp_length
+        self._snr = options.snr
+
+        symbol_length = self._fft_length + self._cp_length
+
+        win = [1 for i in range(self._fft_length)]
+
+        # hard-coded known symbol
+        ks1 = known_symbols_200_1
+        ks2 = known_symbols_200_2
+
+        # ML Sync
+        self.ofdm_sync = ofdm_receiver(self.fg, self._fft_length, symbol_length, self._snr)
+
+        # OFDM Demod
+        self.fft_demod = gr.fft_vcc(self._fft_length, True, win, True)
+        self.ofdm_corr  = gr.ofdm_correlator(self._occupied_tones, self._fft_length,
+                                             self._cp_length, ks1, ks2)
+        self.ofdm_demod = gr.ofdm_bpsk_demapper(self._occupied_tones)
+
+
+        if options.verbose:
+            self._print_verbage()
+
+        self.fg.connect(self.ofdm_sync, self.fft_demod, self.ofdm_corr, self.ofdm_demod)
+        gr.hier_block.__init__(self, self.fg, self.ofdm_sync, self.ofdm_demod)
+        
+    def bits_per_symbol(self=None):   # staticmethod that's also callable on an instance
+        return 1
+    bits_per_symbol = staticmethod(bits_per_symbol)      # make it a static method.  RTFM
+
+    def add_options(normal, expert):
+        """
+        Adds OFDM-specific options to the Options Parser
+        """
+        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 demodulator
+        """
+        print "\nOFDM Demodulator:"
+        print "FFT length:      %3d"   % (self._fft_length)
+        print "Occupied Tones:  %3d"   % (self._occupied_tones)
+        print "CP length:       %3d"   % (self._cp_length)
+
+
+# generated in python using:
+# import random
+# pn = [2.0*random.randint(0,1)-1.0 for i in range(self._occupied_tones)]
+
+known_symbols_200_1 = [1.0, 1.0, -1.0, 1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 1.0, 1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, 1.0, -1.0, -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, -1.0, -1.0, -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, -1.0, 1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0]
+        
+known_symbols_200_2 = [-1.0, -1.0, -1.0, 1.0, 1.0, 1.0, -1.0, -1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, -1.0, -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0, -1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0, -1.0, -1.0, -1.0, -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, -1.0, 1.0, 1.0, 1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, 1.0, 1.0, -1.0, -1.0, 1.0, 1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0, -1.0, -1.0, 1.0, -1.0, 1.0, -1.0, 1.0, -1.0, -1.0, -1.0, -1.0, -1.0, 1.0, -1.0, -1.0, -1.0, 1.0, 1.0, 1.0]