added an example in grc that uses trellis structures

git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@10010 221aa14e-8319-0410-a670-987f0aec2ac5

3 files changed, 2058 insertions, 0 deletions

diff --git a/grc/examples/trellis/Makefile.am b/grc/examples/trellis/Makefile.am
new file mode 100644
index 000000000..1fb6b7742
--- /dev/null
+++ b/grc/examples/trellis/Makefile.am
@@ -0,0 +1,30 @@
+#
+# Copyright 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.
+#
+
+include $(top_srcdir)/grc/Makefile.inc
+
+ourdatadir = $(grc_examples_prefix)/trellis
+
+DATA_FILES = interference_cancellation.grc
+
+ourdata_DATA = $(DATA_FILES)
+
+EXTRA_DIST = $(DATA_FILES)
diff --git a/grc/examples/trellis/interference_cancellation.grc b/grc/examples/trellis/interference_cancellation.grc
new file mode 100644
index 000000000..4065845fb
--- /dev/null
+++ b/grc/examples/trellis/interference_cancellation.grc
@@ -0,0 +1,2012 @@
+<?xml version='1.0' encoding='ASCII'?>
+<flow_graph>
+  <timestamp>Tue Nov 18 00:48:20 2008</timestamp>
+  <block>
+    <key>options</key>
+    <param>
+      <key>id</key>
+      <value>int_cancellation</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>Superposition Coding</value>
+    </param>
+    <param>
+      <key>author</key>
+      <value>AA</value>
+    </param>
+    <param>
+      <key>description</key>
+      <value>gnuradio flow graph</value>
+    </param>
+    <param>
+      <key>window_size</key>
+      <value>2048, 2048</value>
+    </param>
+    <param>
+      <key>generate_options</key>
+      <value>wx_gui</value>
+    </param>
+    <param>
+      <key>category</key>
+      <value>Custom</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(10, 10)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>alpha</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>P1/P</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>0.6</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_length</key>
+      <value>200</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(243, 11)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable_slider</key>
+    <param>
+      <key>id</key>
+      <value>snr_db</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>label</key>
+      <value>P/sigma^2 (dB)</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>16</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>20</value>
+    </param>
+    <param>
+      <key>num_steps</key>
+      <value>100</value>
+    </param>
+    <param>
+      <key>slider_length</key>
+      <value>200</value>
+    </param>
+    <param>
+      <key>slider_type</key>
+      <value>horizontal</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(447, 14)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>noisevar</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>10**(-snr_db/10)</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(637, 13)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>random_source_x</key>
+    <param>
+      <key>id</key>
+      <value>random_source_x_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>num_samps</key>
+      <value>1000</value>
+    </param>
+    <param>
+      <key>repeat</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(21, 170)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_chunks_to_symbols_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_chunks_to_symbols_xx_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>in_type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>out_type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>symbol_table</key>
+      <value>1,1j,-1j,-1</value>
+    </param>
+    <param>
+      <key>dimension</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(665, 187)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_multiply_const_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_multiply_const_vxx_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>const</key>
+      <value>alpha**0.5</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(988, 196)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>random_source_x</key>
+    <param>
+      <key>id</key>
+      <value>random_source_x_1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>min</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>num_samps</key>
+      <value>1000</value>
+    </param>
+    <param>
+      <key>repeat</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(25, 291)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_chunks_to_symbols_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_chunks_to_symbols_xx_1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>in_type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>out_type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>symbol_table</key>
+      <value>1,1j,-1j,-1</value>
+    </param>
+    <param>
+      <key>dimension</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(660, 311)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_multiply_const_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_multiply_const_vxx_1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>const</key>
+      <value>(1-alpha)**0.5</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(994, 319)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_add_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_add_vxx_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1224, 244)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_add_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_add_vxx_1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1400, 262)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_noise_source_x</key>
+    <param>
+      <key>id</key>
+      <value>gr_noise_source_x_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>noise_type</key>
+      <value>gr.GR_GAUSSIAN</value>
+    </param>
+    <param>
+      <key>amp</key>
+      <value>noisevar</value>
+    </param>
+    <param>
+      <key>seed</key>
+      <value>42</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1146, 369)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_constellationsink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_constellationsink2_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>Constellation Plot</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>R</value>
+    </param>
+    <param>
+      <key>frame_decim</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>marker</key>
+      <value>set_format_plus</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value></value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1301, 74)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sub_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_sub_xx_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(536, 529)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_multiply_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_multiply_vxx_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(771, 525)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_short_to_float</key>
+    <param>
+      <key>id</key>
+      <value>gr_short_to_float_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(994, 545)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sub_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_sub_xx_3</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(535, 792)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_multiply_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_multiply_vxx_1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(785, 779)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_short_to_float</key>
+    <param>
+      <key>id</key>
+      <value>gr_short_to_float_2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1005, 798)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_chunks_to_symbols_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_chunks_to_symbols_xx_2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>in_type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>out_type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>symbol_table</key>
+      <value>1,1j,-1j,-1</value>
+    </param>
+    <param>
+      <key>dimension</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(405, 998)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_multiply_const_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_multiply_const_vxx_2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>const</key>
+      <value>alpha**0.5</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(710, 1008)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sub_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_sub_xx_2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(944, 978)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sub_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_sub_xx_1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(540, 1141)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_multiply_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_multiply_vxx_2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(796, 1136)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_short_to_float</key>
+    <param>
+      <key>id</key>
+      <value>gr_short_to_float_1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1009, 1156)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_chunks_to_symbols_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_chunks_to_symbols_xx_2_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>in_type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>out_type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>symbol_table</key>
+      <value>1,1j,-1j,-1</value>
+    </param>
+    <param>
+      <key>dimension</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(420, 1368)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_multiply_const_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_multiply_const_vxx_2_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>const</key>
+      <value>(1-alpha)**0.5</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(733, 1374)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sub_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_sub_xx_2_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>complex</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(975, 1342)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_sub_xx</key>
+    <param>
+      <key>id</key>
+      <value>gr_sub_xx_1_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(559, 1536)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_multiply_vxx</key>
+    <param>
+      <key>id</key>
+      <value>gr_multiply_vxx_2_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>short</value>
+    </param>
+    <param>
+      <key>num_inputs</key>
+      <value>2</value>
+    </param>
+    <param>
+      <key>vlen</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(771, 1530)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>gr_short_to_float</key>
+    <param>
+      <key>id</key>
+      <value>gr_short_to_float_1_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1010, 1551)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_numbersink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_numbersink2_2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>BER 2 (raw)</value>
+    </param>
+    <param>
+      <key>units</key>
+      <value>BER</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>R</value>
+    </param>
+    <param>
+      <key>base_value</key>
+      <value>0.0</value>
+    </param>
+    <param>
+      <key>min_value</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max_value</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>factor</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>decimal_places</key>
+      <value>6</value>
+    </param>
+    <param>
+      <key>ref_level</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>number_rate</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>avg_alpha</key>
+      <value>0.001</value>
+    </param>
+    <param>
+      <key>options</key>
+      <value>average</value>
+    </param>
+    <param>
+      <key>show_gauge</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>0,1,1,1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1260, 659)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_numbersink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_numbersink2_3</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>BER 2 (after cancelling user 1)</value>
+    </param>
+    <param>
+      <key>units</key>
+      <value>BER</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>R</value>
+    </param>
+    <param>
+      <key>base_value</key>
+      <value>0.0</value>
+    </param>
+    <param>
+      <key>min_value</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max_value</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>factor</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>decimal_places</key>
+      <value>6</value>
+    </param>
+    <param>
+      <key>ref_level</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>number_rate</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>avg_alpha</key>
+      <value>0.001</value>
+    </param>
+    <param>
+      <key>options</key>
+      <value>average</value>
+    </param>
+    <param>
+      <key>show_gauge</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>1,1,1,1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1262, 1020)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_numbersink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_numbersink2_3_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>BER 1 (after cancelling user 2)</value>
+    </param>
+    <param>
+      <key>units</key>
+      <value>BER</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>R</value>
+    </param>
+    <param>
+      <key>base_value</key>
+      <value>0.0</value>
+    </param>
+    <param>
+      <key>min_value</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max_value</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>factor</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>decimal_places</key>
+      <value>6</value>
+    </param>
+    <param>
+      <key>ref_level</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>number_rate</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>avg_alpha</key>
+      <value>0.001</value>
+    </param>
+    <param>
+      <key>options</key>
+      <value>average</value>
+    </param>
+    <param>
+      <key>show_gauge</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>1,0,1,1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1269, 1417)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>wxgui_numbersink2</key>
+    <param>
+      <key>id</key>
+      <value>wxgui_numbersink2_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>float</value>
+    </param>
+    <param>
+      <key>title</key>
+      <value>BER 1 (raw)</value>
+    </param>
+    <param>
+      <key>units</key>
+      <value>BER</value>
+    </param>
+    <param>
+      <key>samp_rate</key>
+      <value>R</value>
+    </param>
+    <param>
+      <key>base_value</key>
+      <value>0.0</value>
+    </param>
+    <param>
+      <key>min_value</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>max_value</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>factor</key>
+      <value>1.0</value>
+    </param>
+    <param>
+      <key>decimal_places</key>
+      <value>6</value>
+    </param>
+    <param>
+      <key>ref_level</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>number_rate</key>
+      <value>15</value>
+    </param>
+    <param>
+      <key>avg_alpha</key>
+      <value>0.001</value>
+    </param>
+    <param>
+      <key>options</key>
+      <value>average</value>
+    </param>
+    <param>
+      <key>show_gauge</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>grid_pos</key>
+      <value>0,0,1,1</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(1267, 410)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>R</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>10e3</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(748, 12)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>trellis_encoder_xx</key>
+    <param>
+      <key>id</key>
+      <value>trellis_encoder_xx_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>ss</value>
+    </param>
+    <param>
+      <key>fsm_args</key>
+      <value>prefix+"gr-trellis/src/examples/fsm_files/awgn1o2_16.fsm"</value>
+    </param>
+    <param>
+      <key>init_state</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(334, 190)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>trellis_encoder_xx</key>
+    <param>
+      <key>id</key>
+      <value>trellis_encoder_xx_1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>ss</value>
+    </param>
+    <param>
+      <key>fsm_args</key>
+      <value>prefix+"gr-trellis/src/examples/fsm_files/awgn1o2_16.fsm"</value>
+    </param>
+    <param>
+      <key>init_state</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(336, 311)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>trellis_viterbi_combined_xx</key>
+    <param>
+      <key>id</key>
+      <value>trellis_viterbi_combined_xx_1</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>c</value>
+    </param>
+    <param>
+      <key>out_type</key>
+      <value>s</value>
+    </param>
+    <param>
+      <key>fsm_args</key>
+      <value>prefix+"gr-trellis/src/examples/fsm_files/awgn1o2_16.fsm"</value>
+    </param>
+    <param>
+      <key>block_size</key>
+      <value>1000</value>
+    </param>
+    <param>
+      <key>init_state</key>
+      <value>-1</value>
+    </param>
+    <param>
+      <key>final_state</key>
+      <value>-1</value>
+    </param>
+    <param>
+      <key>dim</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>table</key>
+      <value>alpha**0.5*1,alpha**0.5*1j,alpha**0.5*(-1j),alpha**0.5*(-1)</value>
+    </param>
+    <param>
+      <key>metric_type</key>
+      <value>trellis.TRELLIS_EUCLIDEAN</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(79, 501)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>trellis_viterbi_combined_xx</key>
+    <param>
+      <key>id</key>
+      <value>trellis_viterbi_combined_xx_2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>c</value>
+    </param>
+    <param>
+      <key>out_type</key>
+      <value>s</value>
+    </param>
+    <param>
+      <key>fsm_args</key>
+      <value>prefix+"gr-trellis/src/examples/fsm_files/awgn1o2_16.fsm"</value>
+    </param>
+    <param>
+      <key>block_size</key>
+      <value>1000</value>
+    </param>
+    <param>
+      <key>init_state</key>
+      <value>-1</value>
+    </param>
+    <param>
+      <key>final_state</key>
+      <value>-1</value>
+    </param>
+    <param>
+      <key>dim</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>table</key>
+      <value>(1-alpha)**0.5*1,(1-alpha)**0.5*1j,(1-alpha)**0.5*(-1j),(1-alpha)**0.5*(-1)</value>
+    </param>
+    <param>
+      <key>metric_type</key>
+      <value>trellis.TRELLIS_EUCLIDEAN</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(82, 766)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>trellis_encoder_xx</key>
+    <param>
+      <key>id</key>
+      <value>trellis_encoder_xx_2</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>ss</value>
+    </param>
+    <param>
+      <key>fsm_args</key>
+      <value>prefix+"gr-trellis/src/examples/fsm_files/awgn1o2_16.fsm"</value>
+    </param>
+    <param>
+      <key>init_state</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(89, 998)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>trellis_viterbi_combined_xx</key>
+    <param>
+      <key>id</key>
+      <value>trellis_viterbi_combined_xx_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>c</value>
+    </param>
+    <param>
+      <key>out_type</key>
+      <value>s</value>
+    </param>
+    <param>
+      <key>fsm_args</key>
+      <value>prefix+"gr-trellis/src/examples/fsm_files/awgn1o2_16.fsm"</value>
+    </param>
+    <param>
+      <key>block_size</key>
+      <value>1000</value>
+    </param>
+    <param>
+      <key>init_state</key>
+      <value>-1</value>
+    </param>
+    <param>
+      <key>final_state</key>
+      <value>-1</value>
+    </param>
+    <param>
+      <key>dim</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>table</key>
+      <value>(1-alpha)**0.5*1,(1-alpha)**0.5*1j,(1-alpha)**0.5*(-1j),(1-alpha)**0.5*(-1)</value>
+    </param>
+    <param>
+      <key>metric_type</key>
+      <value>trellis.TRELLIS_EUCLIDEAN</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(83, 1111)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>trellis_encoder_xx</key>
+    <param>
+      <key>id</key>
+      <value>trellis_encoder_xx_2_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>ss</value>
+    </param>
+    <param>
+      <key>fsm_args</key>
+      <value>prefix+"gr-trellis/src/examples/fsm_files/awgn1o2_16.fsm"</value>
+    </param>
+    <param>
+      <key>init_state</key>
+      <value>0</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(105, 1367)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>trellis_viterbi_combined_xx</key>
+    <param>
+      <key>id</key>
+      <value>trellis_viterbi_combined_xx_0_0</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>type</key>
+      <value>c</value>
+    </param>
+    <param>
+      <key>out_type</key>
+      <value>s</value>
+    </param>
+    <param>
+      <key>fsm_args</key>
+      <value>prefix+"gr-trellis/src/examples/fsm_files/awgn1o2_16.fsm"</value>
+    </param>
+    <param>
+      <key>block_size</key>
+      <value>1000</value>
+    </param>
+    <param>
+      <key>init_state</key>
+      <value>-1</value>
+    </param>
+    <param>
+      <key>final_state</key>
+      <value>-1</value>
+    </param>
+    <param>
+      <key>dim</key>
+      <value>1</value>
+    </param>
+    <param>
+      <key>table</key>
+      <value>alpha**0.5*1,alpha**0.5*1j,alpha**0.5*(-1j),alpha**0.5*(-1)</value>
+    </param>
+    <param>
+      <key>metric_type</key>
+      <value>trellis.TRELLIS_EUCLIDEAN</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(75, 1495)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <block>
+    <key>variable</key>
+    <param>
+      <key>id</key>
+      <value>prefix</value>
+    </param>
+    <param>
+      <key>_enabled</key>
+      <value>True</value>
+    </param>
+    <param>
+      <key>value</key>
+      <value>"../../../"</value>
+    </param>
+    <param>
+      <key>_coordinate</key>
+      <value>(871, 14)</value>
+    </param>
+    <param>
+      <key>_rotation</key>
+      <value>0</value>
+    </param>
+  </block>
+  <connection>
+    <source_block_id>random_source_x_1</source_block_id>
+    <sink_block_id>trellis_encoder_xx_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>trellis_encoder_xx_0</source_block_id>
+    <sink_block_id>gr_chunks_to_symbols_xx_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>trellis_encoder_xx_1</source_block_id>
+    <sink_block_id>gr_chunks_to_symbols_xx_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_chunks_to_symbols_xx_0</source_block_id>
+    <sink_block_id>gr_multiply_const_vxx_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_multiply_const_vxx_0</source_block_id>
+    <sink_block_id>gr_add_vxx_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx_0</source_block_id>
+    <sink_block_id>gr_add_vxx_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_noise_source_x_0</source_block_id>
+    <sink_block_id>gr_add_vxx_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx_1</source_block_id>
+    <sink_block_id>wxgui_constellationsink2_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_chunks_to_symbols_xx_1</source_block_id>
+    <sink_block_id>gr_multiply_const_vxx_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_multiply_const_vxx_1</source_block_id>
+    <sink_block_id>gr_add_vxx_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sub_xx_0</source_block_id>
+    <sink_block_id>gr_multiply_vxx_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sub_xx_0</source_block_id>
+    <sink_block_id>gr_multiply_vxx_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_multiply_vxx_0</source_block_id>
+    <sink_block_id>gr_short_to_float_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_short_to_float_0</source_block_id>
+    <sink_block_id>wxgui_numbersink2_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_multiply_vxx_2</source_block_id>
+    <sink_block_id>gr_short_to_float_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>random_source_x_0</source_block_id>
+    <sink_block_id>trellis_encoder_xx_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx_1</source_block_id>
+    <sink_block_id>trellis_viterbi_combined_xx_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>random_source_x_0</source_block_id>
+    <sink_block_id>gr_sub_xx_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>trellis_viterbi_combined_xx_1</source_block_id>
+    <sink_block_id>gr_sub_xx_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>trellis_viterbi_combined_xx_0</source_block_id>
+    <sink_block_id>gr_sub_xx_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>random_source_x_1</source_block_id>
+    <sink_block_id>gr_sub_xx_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sub_xx_1</source_block_id>
+    <sink_block_id>gr_multiply_vxx_2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sub_xx_1</source_block_id>
+    <sink_block_id>gr_multiply_vxx_2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sub_xx_2</source_block_id>
+    <sink_block_id>trellis_viterbi_combined_xx_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx_1</source_block_id>
+    <sink_block_id>gr_sub_xx_2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>trellis_encoder_xx_2</source_block_id>
+    <sink_block_id>gr_chunks_to_symbols_xx_2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_chunks_to_symbols_xx_2</source_block_id>
+    <sink_block_id>gr_multiply_const_vxx_2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_multiply_const_vxx_2</source_block_id>
+    <sink_block_id>gr_sub_xx_2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>trellis_viterbi_combined_xx_1</source_block_id>
+    <sink_block_id>trellis_encoder_xx_2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_multiply_vxx_1</source_block_id>
+    <sink_block_id>gr_short_to_float_2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_short_to_float_2</source_block_id>
+    <sink_block_id>wxgui_numbersink2_2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>trellis_viterbi_combined_xx_2</source_block_id>
+    <sink_block_id>gr_sub_xx_3</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sub_xx_3</source_block_id>
+    <sink_block_id>gr_multiply_vxx_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sub_xx_3</source_block_id>
+    <sink_block_id>gr_multiply_vxx_1</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx_1</source_block_id>
+    <sink_block_id>trellis_viterbi_combined_xx_2</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>random_source_x_1</source_block_id>
+    <sink_block_id>gr_sub_xx_3</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_short_to_float_1</source_block_id>
+    <sink_block_id>wxgui_numbersink2_3</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>trellis_encoder_xx_2_0</source_block_id>
+    <sink_block_id>gr_chunks_to_symbols_xx_2_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_chunks_to_symbols_xx_2_0</source_block_id>
+    <sink_block_id>gr_multiply_const_vxx_2_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>trellis_viterbi_combined_xx_2</source_block_id>
+    <sink_block_id>trellis_encoder_xx_2_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_multiply_vxx_2_0</source_block_id>
+    <sink_block_id>gr_short_to_float_1_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>trellis_viterbi_combined_xx_0_0</source_block_id>
+    <sink_block_id>gr_sub_xx_1_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sub_xx_1_0</source_block_id>
+    <sink_block_id>gr_multiply_vxx_2_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sub_xx_1_0</source_block_id>
+    <sink_block_id>gr_multiply_vxx_2_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_sub_xx_2_0</source_block_id>
+    <sink_block_id>trellis_viterbi_combined_xx_0_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_short_to_float_1_0</source_block_id>
+    <sink_block_id>wxgui_numbersink2_3_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_add_vxx_1</source_block_id>
+    <sink_block_id>gr_sub_xx_2_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>random_source_x_0</source_block_id>
+    <sink_block_id>gr_sub_xx_1_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>0</sink_key>
+  </connection>
+  <connection>
+    <source_block_id>gr_multiply_const_vxx_2_0</source_block_id>
+    <sink_block_id>gr_sub_xx_2_0</sink_block_id>
+    <source_key>0</source_key>
+    <sink_key>1</sink_key>
+  </connection>
+</flow_graph>
diff --git a/grc/examples/trellis/readme.txt b/grc/examples/trellis/readme.txt
new file mode 100644
index 000000000..d620fd628
--- /dev/null
+++ b/grc/examples/trellis/readme.txt
@@ -0,0 +1,16 @@
+This is an example of using gr-trellis in grc.
+
+Two users are transmitting simultaneously using convolutionally encoded QPSK, each with power P1=alpha*P and P2=(1-alpha)*P.
+The combined signal is observed in noise and four different receivers are considered:
+1) A viterbi decoder decoding user 1 assuming user 2 is noise
+2) A viterbi decoder decoding user 2 assuming user 1 is noise
+3) A viterbi decoder decoding user 1 first 
+   and then reencoding this signal, subtracting it from the observation 
+   and then running a Viterbi decoder decoding user 2
+4) A viterbi decoder decoding user 2 first 
+   and then reencoding this signal, subtracting it from the observation 
+   and then running a Viterbi decoder decoding user 1
+
+You can change the signal to noise ratio P/sigma^2 and the allocation of power to the two users, alpha.
+
+Enjoy.