python/trx: install helper classes as a grgsm submodule
diff --git a/python/trx/CMakeLists.txt b/python/trx/CMakeLists.txt
index a0ad38f..d8e9164 100644
--- a/python/trx/CMakeLists.txt
+++ b/python/trx/CMakeLists.txt
@@ -19,9 +19,10 @@
 
 GR_PYTHON_INSTALL(
     FILES
-    ctrl_if_bb.py
+    __init__.py
+    udp_link.py
     ctrl_if.py
+    ctrl_if_bb.py
     fake_pm.py
-    radio_if.py
-    udp_link.py DESTINATION ${GR_PYTHON_DIR}/grgsm
+    radio_if.py DESTINATION ${GR_PYTHON_DIR}/grgsm/trx
 )
diff --git a/python/trx/__init__.py b/python/trx/__init__.py
new file mode 100644
index 0000000..81e569c
--- /dev/null
+++ b/python/trx/__init__.py
@@ -0,0 +1,27 @@
+#
+# Copyright 2008,2009 Free Software Foundation, Inc.
+#
+# This application 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.
+#
+# This application 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 this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+#
+
+'''
+This is a set of helper classes for the grgsm_trx application.
+'''
+
+from udp_link import udp_link
+from ctrl_if import ctrl_if
+from ctrl_if_bb import ctrl_if_bb
+from fake_pm import fake_pm
+from radio_if import radio_if