Added OFDM Mod and Demod to GRC (cough cough... kludge).

Generalized the packet mod and demod stuff to accept the OFDM blocks.



git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@10585 221aa14e-8319-0410-a670-987f0aec2ac5

9 files changed, 401 insertions, 100 deletions

diff --git a/grc/data/platforms/python/block_tree.xml b/grc/data/platforms/python/block_tree.xml
index b56073bbf..bb2d681f0 100644
--- a/grc/data/platforms/python/block_tree.xml
+++ b/grc/data/platforms/python/block_tree.xml
@@ -213,6 +213,9 @@
 		<block>blks2_qamx_mod</block>
 		<block>blks2_qamx_demod</block>
 
+		<block>blks2_ofdm_mod</block>
+		<block>blks2_ofdm_demod</block>
+
 		<block>blks2_synthesis_filterbank</block>
 		<block>blks2_analysis_filterbank</block>
 	</cat>
diff --git a/grc/data/platforms/python/blocks/Makefile.am b/grc/data/platforms/python/blocks/Makefile.am
index 3655b1311..6b09050f3 100644
--- a/grc/data/platforms/python/blocks/Makefile.am
+++ b/grc/data/platforms/python/blocks/Makefile.am
@@ -42,6 +42,8 @@ dist_ourdata_DATA = \
 	blks2_logpwrfft_x.xml \
 	blks2_nbfm_rx.xml \
 	blks2_nbfm_tx.xml \
+	blks2_ofdm_demod.xml \
+	blks2_ofdm_mod.xml \
 	blks2_packet_decoder.xml \
 	blks2_packet_encoder.xml \
 	blks2_qamx_demod.xml \
diff --git a/grc/data/platforms/python/blocks/blks2_ofdm_demod.xml b/grc/data/platforms/python/blocks/blks2_ofdm_demod.xml
new file mode 100644
index 000000000..ac5ee4795
--- /dev/null
+++ b/grc/data/platforms/python/blocks/blks2_ofdm_demod.xml
@@ -0,0 +1,122 @@
+<?xml version="1.0"?>
+<!--
+###################################################
+##OFDM Demod
+###################################################
+ -->
+<block>
+	<name>OFDM Demod</name>
+	<key>blks2_ofdm_demod</key>
+	<import>from grc_gnuradio import blks2 as grc_blks2</import>
+	<import>from gnuradio import blks2</import>
+	<make>grc_blks2.packet_demod_$(type.fcn)(blks2.ofdm_demod(
+		options=grc_blks2.options(
+			modulation="$modulation",
+			fft_length=$fft_length,
+			occupied_tones=$occupied_tones,
+			cp_length=$cp_length,
+			snr=$snr,
+			log=None,
+			verbose=None,
+		),
+		callback=lambda ok, payload: self.$(id).recv_pkt(ok, payload),
+	),
+)</make>
+	<param>
+		<name>Output Type</name>
+		<key>type</key>
+		<value>float</value>
+		<type>enum</type>
+		<option>
+			<name>Complex</name>
+			<key>complex</key>
+			<opt>fcn:c</opt>
+		</option>
+		<option>
+			<name>Float</name>
+			<key>float</key>
+			<opt>fcn:f</opt>
+		</option>
+		<option>
+			<name>Int</name>
+			<key>int</key>
+			<opt>fcn:i</opt>
+		</option>
+		<option>
+			<name>Short</name>
+			<key>short</key>
+			<opt>fcn:s</opt>
+		</option>
+		<option>
+			<name>Byte</name>
+			<key>byte</key>
+			<opt>fcn:b</opt>
+		</option>
+	</param>
+	<param>
+		<name>Modulation</name>
+		<key>modulation</key>
+		<type>enum</type>
+		<option>
+			<name>BPSK</name>
+			<key>bpsk</key>
+		</option>
+		<option>
+			<name>QPSK</name>
+			<key>qpsk</key>
+		</option>
+		<option>
+			<name>8PSK</name>
+			<key>8psk</key>
+		</option>
+		<option>
+			<name>QAM8</name>
+			<key>qam8</key>
+		</option>
+		<option>
+			<name>QAM16</name>
+			<key>qam16</key>
+		</option>
+		<option>
+			<name>QAM64</name>
+			<key>qam64</key>
+		</option>
+		<option>
+			<name>QAM256</name>
+			<key>qam256</key>
+		</option>
+	</param>
+	<param>
+		<name>FFT Length</name>
+		<key>fft_length</key>
+		<value>512</value>
+		<type>int</type>
+	</param>
+	<param>
+		<name>Occupied Tones</name>
+		<key>occupied_tones</key>
+		<value>200</value>
+		<type>int</type>
+	</param>
+	<param>
+		<name>Cyclic Prefix Length</name>
+		<key>cp_length</key>
+		<value>128</value>
+		<type>int</type>
+	</param>
+	<param>
+		<name>SNR</name>
+		<key>snr</key>
+		<value>10</value>
+		<type>real</type>
+	</param>
+	<sink>
+		<name>in</name>
+		<type>complex</type>
+	</sink>
+	<source>
+		<name>out</name>
+		<type>$type</type>
+	</source>
+	<doc>Payload Length: 0 for automatic.</doc>
+</block>
diff --git a/grc/data/platforms/python/blocks/blks2_ofdm_mod.xml b/grc/data/platforms/python/blocks/blks2_ofdm_mod.xml
new file mode 100644
index 000000000..2c54d10f4
--- /dev/null
+++ b/grc/data/platforms/python/blocks/blks2_ofdm_mod.xml
@@ -0,0 +1,135 @@
+<?xml version="1.0"?>
+<!--
+###################################################
+##OFDM Mod
+###################################################
+ -->
+<block>
+	<name>OFDM Mod</name>
+	<key>blks2_ofdm_mod</key>
+	<import>from grc_gnuradio import blks2 as grc_blks2</import>
+	<import>from gnuradio import blks2</import>
+	<make>grc_blks2.packet_mod_$(type.fcn)(blks2.ofdm_mod(
+		options=grc_blks2.options(
+			modulation="$modulation",
+			fft_length=$fft_length,
+			occupied_tones=$occupied_tones,
+			cp_length=$cp_length,
+			pad_for_usrp=$pad_for_usrp,
+			log=None,
+			verbose=None,
+		),
+	),
+	payload_length=$payload_length,
+)</make>
+	<param>
+		<name>Input Type</name>
+		<key>type</key>
+		<value>float</value>
+		<type>enum</type>
+		<option>
+			<name>Complex</name>
+			<key>complex</key>
+			<opt>fcn:c</opt>
+		</option>
+		<option>
+			<name>Float</name>
+			<key>float</key>
+			<opt>fcn:f</opt>
+		</option>
+		<option>
+			<name>Int</name>
+			<key>int</key>
+			<opt>fcn:i</opt>
+		</option>
+		<option>
+			<name>Short</name>
+			<key>short</key>
+			<opt>fcn:s</opt>
+		</option>
+		<option>
+			<name>Byte</name>
+			<key>byte</key>
+			<opt>fcn:b</opt>
+		</option>
+	</param>
+	<param>
+		<name>Modulation</name>
+		<key>modulation</key>
+		<type>enum</type>
+		<option>
+			<name>BPSK</name>
+			<key>bpsk</key>
+		</option>
+		<option>
+			<name>QPSK</name>
+			<key>qpsk</key>
+		</option>
+		<option>
+			<name>8PSK</name>
+			<key>8psk</key>
+		</option>
+		<option>
+			<name>QAM8</name>
+			<key>qam8</key>
+		</option>
+		<option>
+			<name>QAM16</name>
+			<key>qam16</key>
+		</option>
+		<option>
+			<name>QAM64</name>
+			<key>qam64</key>
+		</option>
+		<option>
+			<name>QAM256</name>
+			<key>qam256</key>
+		</option>
+	</param>
+	<param>
+		<name>FFT Length</name>
+		<key>fft_length</key>
+		<value>512</value>
+		<type>int</type>
+	</param>
+	<param>
+		<name>Occupied Tones</name>
+		<key>occupied_tones</key>
+		<value>200</value>
+		<type>int</type>
+	</param>
+	<param>
+		<name>Cyclic Prefix Length</name>
+		<key>cp_length</key>
+		<value>128</value>
+		<type>int</type>
+	</param>
+	<param>
+		<name>Pad for USRP</name>
+		<key>pad_for_usrp</key>
+		<type>enum</type>
+		<option>
+			<name>Yes</name>
+			<key>True</key>
+		</option>
+		<option>
+			<name>No</name>
+			<key>False</key>
+		</option>
+	</param>
+	<param>
+		<name>Payload Length</name>
+		<key>payload_length</key>
+		<value>0</value>
+		<type>int</type>
+	</param>
+	<sink>
+		<name>in</name>
+		<type>$type</type>
+	</sink>
+	<source>
+		<name>out</name>
+		<type>complex</type>
+	</source>
+	<doc>Payload Length: 0 for automatic.</doc>
+</block>
diff --git a/grc/data/platforms/python/blocks/blks2_packet_decoder.xml b/grc/data/platforms/python/blocks/blks2_packet_decoder.xml
index d360bc177..07b0d1f2e 100644
--- a/grc/data/platforms/python/blocks/blks2_packet_decoder.xml
+++ b/grc/data/platforms/python/blocks/blks2_packet_decoder.xml
@@ -8,11 +8,11 @@
 	<name>Packet Decoder</name>
 	<key>blks2_packet_decoder</key>
 	<import>from grc_gnuradio import blks2 as grc_blks2</import>
-	<import>from gnuradio import gr</import>
-	<make>grc_blks2.packet_decoder(
-	item_size_out=$type.size*$vlen,
-	access_code=$access_code,
-	threshold=$threshold,
+	<make>grc_blks2.packet_demod_$(type.fcn)(grc_blks2.packet_decoder(
+		access_code=$access_code,
+		threshold=$threshold,
+		callback=lambda ok, payload: self.$(id).recv_pkt(ok, payload),
+	),
 )</make>
 	<param>
 		<name>Output Type</name>
@@ -22,27 +22,27 @@
 		<option>
 			<name>Complex</name>
 			<key>complex</key>
-			<opt>size:gr.sizeof_gr_complex</opt>
+			<opt>fcn:c</opt>
 		</option>
 		<option>
 			<name>Float</name>
 			<key>float</key>
-			<opt>size:gr.sizeof_float</opt>
+			<opt>fcn:f</opt>
 		</option>
 		<option>
 			<name>Int</name>
 			<key>int</key>
-			<opt>size:gr.sizeof_int</opt>
+			<opt>fcn:i</opt>
 		</option>
 		<option>
 			<name>Short</name>
 			<key>short</key>
-			<opt>size:gr.sizeof_short</opt>
+			<opt>fcn:s</opt>
 		</option>
 		<option>
 			<name>Byte</name>
 			<key>byte</key>
-			<opt>size:gr.sizeof_char</opt>
+			<opt>fcn:b</opt>
 		</option>
 	</param>
 	<param>
@@ -57,13 +57,6 @@
 		<value>-1</value>
 		<type>int</type>
 	</param>
-	<param>
-		<name>Vec Length</name>
-		<key>vlen</key>
-		<value>1</value>
-		<type>int</type>
-	</param>
-	<check>$vlen &gt; 0</check>
 	<sink>
 		<name>in</name>
 		<type>byte</type>
@@ -71,11 +64,12 @@
 	<source>
 		<name>out</name>
 		<type>$type</type>
-		<vlen>$vlen</vlen>
 	</source>
 	<doc>
 Packet decoder block, for use with the gnuradio demodulator blocks: gmsk, psk, qam.
 
-Access Code: string of 1's and 0's, leave blank for default.
+Access Code: string of 1's and 0's, leave blank for automatic.
+
+Threshold: -1 for automatic.
 	</doc>
 </block>
diff --git a/grc/data/platforms/python/blocks/blks2_packet_encoder.xml b/grc/data/platforms/python/blocks/blks2_packet_encoder.xml
index ea9927225..b184ebd31 100644
--- a/grc/data/platforms/python/blocks/blks2_packet_encoder.xml
+++ b/grc/data/platforms/python/blocks/blks2_packet_encoder.xml
@@ -8,13 +8,12 @@
 	<name>Packet Encoder</name>
 	<key>blks2_packet_encoder</key>
 	<import>from grc_gnuradio import blks2 as grc_blks2</import>
-	<import>from gnuradio import gr</import>
-	<make>grc_blks2.packet_encoder(
-	item_size_in=$type.size*$vlen,
-	samples_per_symbol=$samples_per_symbol,
-	bits_per_symbol=$bits_per_symbol,
-	access_code=$access_code,
-	pad_for_usrp=$pad_for_usrp,
+	<make>grc_blks2.packet_mod_$(type.fcn)(grc_blks2.packet_encoder(
+		samples_per_symbol=$samples_per_symbol,
+		bits_per_symbol=$bits_per_symbol,
+		access_code=$access_code,
+		pad_for_usrp=$pad_for_usrp,
+	),
 	payload_length=$payload_length,
 )</make>
 	<param>
@@ -25,27 +24,27 @@
 		<option>
 			<name>Complex</name>
 			<key>complex</key>
-			<opt>size:gr.sizeof_gr_complex</opt>
+			<opt>fcn:c</opt>
 		</option>
 		<option>
 			<name>Float</name>
 			<key>float</key>
-			<opt>size:gr.sizeof_float</opt>
+			<opt>fcn:f</opt>
 		</option>
 		<option>
 			<name>Int</name>
 			<key>int</key>
-			<opt>size:gr.sizeof_int</opt>
+			<opt>fcn:i</opt>
 		</option>
 		<option>
 			<name>Short</name>
 			<key>short</key>
-			<opt>size:gr.sizeof_short</opt>
+			<opt>fcn:s</opt>
 		</option>
 		<option>
 			<name>Byte</name>
 			<key>byte</key>
-			<opt>size:gr.sizeof_char</opt>
+			<opt>fcn:b</opt>
 		</option>
 	</param>
 	<param>
@@ -80,29 +79,23 @@
 	<param>
 		<name>Payload Length</name>
 		<key>payload_length</key>
-		<value>-1</value>
+		<value>0</value>
 		<type>int</type>
 	</param>
-	<param>
-		<name>Vec Length</name>
-		<key>vlen</key>
-		<value>1</value>
-		<type>int</type>
-	</param>
-	<check>$vlen &gt; 0</check>
 	<sink>
 		<name>in</name>
 		<type>$type</type>
-		<vlen>$vlen</vlen>
 	</sink>
 	<source>
 		<name>out</name>
 		<type>byte</type>
 	</source>
 	<doc>
-Packet encoder block, for use with the gnuradio modulator blocks: gmsk, psk, qam.
+Packet encoder block, for use with the gnuradio modulator blocks: gmsk, dpsk, qam.
+
+Access Code: string of 1's and 0's, leave blank for automatic.
 
-Access Code: string of 1's and 0's, leave blank for default.
+Payload Length: 0 for automatic.
 
 Bits/Symbol should be set accordingly:
 	gmsk -> 1
diff --git a/grc/src/grc_gnuradio/blks2/__init__.py b/grc/src/grc_gnuradio/blks2/__init__.py
index 1705a3f9b..185230ab0 100644
--- a/grc/src/grc_gnuradio/blks2/__init__.py
+++ b/grc/src/grc_gnuradio/blks2/__init__.py
@@ -1,4 +1,4 @@
-# Copyright 2008 Free Software Foundation, Inc.
+# Copyright 2008, 2009 Free Software Foundation, Inc.
 #
 # This file is part of GNU Radio
 #
@@ -19,6 +19,8 @@
 #
 
 from selector import selector, valve
-from packet import packet_encoder, packet_decoder
+from packet import options, packet_encoder, packet_decoder, \
+	packet_mod_b, packet_mod_s, packet_mod_i, packet_mod_f, packet_mod_c, \
+	packet_demod_b, packet_demod_s, packet_demod_i, packet_demod_f, packet_demod_c
 from error_rate import error_rate
 from probe import probe_function, probe_avg_mag_sqrd_c, probe_avg_mag_sqrd_f, probe_density_b, probe_mpsk_snr_c
diff --git a/grc/src/grc_gnuradio/blks2/packet.py b/grc/src/grc_gnuradio/blks2/packet.py
index fcdfb9ae2..a305b961e 100644
--- a/grc/src/grc_gnuradio/blks2/packet.py
+++ b/grc/src/grc_gnuradio/blks2/packet.py
@@ -1,4 +1,4 @@
-# Copyright 2008 Free Software Foundation, Inc.
+# Copyright 2008, 2009 Free Software Foundation, Inc.
 #
 # This file is part of GNU Radio
 #
@@ -30,10 +30,16 @@ DEFAULT_MSGQ_LIMIT = 2
 ##threshold for unmaking packets
 DEFAULT_THRESHOLD = 12
 
-#######################################################################################
-## Packet Encoder
-#######################################################################################
+##################################################
+## Options Class for OFDM
+##################################################
+class options(object):
+	def __init__(self, **kwargs):
+		for key, value in kwargs.iteritems(): setattr(self, key, value)
 
+##################################################
+## Packet Encoder
+##################################################
 class _packet_encoder_thread(_threading.Thread):
 
 	def __init__(self, msgq, payload_length, send):
@@ -51,7 +57,7 @@ class _packet_encoder_thread(_threading.Thread):
 			msg = self._msgq.delete_head() #blocking read of message queue
 			sample = sample + msg.to_string() #get the body of the msg as a string
 			while len(sample) >= self._payload_length:
-				payload = sample[0:self._payload_length]
+				payload = sample[:self._payload_length]
 				sample = sample[self._payload_length:]
 				self._send(payload)
 
@@ -60,10 +66,9 @@ class packet_encoder(gr.hier_block2):
 	Hierarchical block for wrapping packet-based modulators.
 	"""
 
-	def __init__(self, item_size_in, samples_per_symbol, bits_per_symbol, access_code='', pad_for_usrp=True, payload_length=-1):
+	def __init__(self, samples_per_symbol, bits_per_symbol, access_code='', pad_for_usrp=True):
 		"""
 		packet_mod constructor.
-		@param item_size_in the size of the input data stream in bytes
 		@param samples_per_symbol number of samples per symbol
 		@param bits_per_symbol number of bits per symbol
 		@param access_code AKA sync vector
@@ -71,7 +76,6 @@ class packet_encoder(gr.hier_block2):
 		@param payload_length number of bytes in a data-stream slice
 		"""
 		#setup parameters
-		self._item_size_in = item_size_in
 		self._samples_per_symbol = samples_per_symbol
 		self._bits_per_symbol = bits_per_symbol
 		self._pad_for_usrp = pad_for_usrp
@@ -81,30 +85,20 @@ class packet_encoder(gr.hier_block2):
 			raise ValueError, "Invalid access_code %r. Must be string of 1's and 0's" % (access_code,)
 		self._access_code = access_code
 		self._pad_for_usrp = pad_for_usrp
-		if payload_length < 0: #get payload length
-			payload_length = DEFAULT_PAYLOAD_LEN
-		if payload_length%self._item_size_in != 0:	#verify that packet length is a multiple of the stream size
-			raise ValueError, 'The packet length: "%d" is not a mutiple of the stream size: "%d".'%(payload_length, self._item_size_in)
-		self._payload_length = payload_length
 		#create blocks
 		msg_source = gr.message_source(gr.sizeof_char, DEFAULT_MSGQ_LIMIT)
 		self._msgq_out = msg_source.msgq()
-		self._msgq_in = gr.msg_queue(DEFAULT_MSGQ_LIMIT)
-		msg_sink = gr.message_sink(self._item_size_in, self._msgq_in, False) #False -> blocking
 		#initialize hier2
 		gr.hier_block2.__init__(
 			self,
 			"packet_encoder",
-			gr.io_signature(1, 1, self._item_size_in), # Input signature
+			gr.io_signature(0, 0, 0), # Input signature
 			gr.io_signature(1, 1, gr.sizeof_char) # Output signature
 		)
 		#connect
-		self.connect(self, msg_sink)
 		self.connect(msg_source, self)
-		#start thread
-		_packet_encoder_thread(self._msgq_in, self._payload_length, self._send_packet)
 
-	def _send_packet(self, payload):
+	def send_pkt(self, payload):
 		"""
 		Wrap the payload in a packet and push onto the message queue.
 		@param payload string, data to send
@@ -119,41 +113,38 @@ class packet_encoder(gr.hier_block2):
 		msg = gr.message_from_string(packet)
 		self._msgq_out.insert_tail(msg)
 
-#######################################################################################
+##################################################
 ## Packet Decoder
-#######################################################################################
-
+##################################################
 class _packet_decoder_thread(_threading.Thread):
 
-    def __init__(self, msgq, callback):
-        _threading.Thread.__init__(self)
-        self.setDaemon(1)
-        self._msgq = msgq
-        self.callback = callback
-        self.keep_running = True
-        self.start()
-
-    def run(self):
-        while self.keep_running:
-            msg = self._msgq.delete_head()
-            ok, payload = packet_utils.unmake_packet(msg.to_string(), int(msg.arg1()))
-            if self.callback:
-                self.callback(ok, payload)
+	def __init__(self, msgq, callback):
+		_threading.Thread.__init__(self)
+		self.setDaemon(1)
+		self._msgq = msgq
+		self.callback = callback
+		self.keep_running = True
+		self.start()
+
+	def run(self):
+		while self.keep_running:
+			msg = self._msgq.delete_head()
+			ok, payload = packet_utils.unmake_packet(msg.to_string(), int(msg.arg1()))
+			if self.callback:
+				self.callback(ok, payload)
 
 class packet_decoder(gr.hier_block2):
 	"""
 	Hierarchical block for wrapping packet-based demodulators.
 	"""
 
-	def __init__(self, item_size_out, access_code='', threshold=-1):
+	def __init__(self, access_code='', threshold=-1, callback=None):
 		"""
 		packet_demod constructor.
-		@param item_size_out the size of the output data stream in bytes
 		@param access_code AKA sync vector
-		@param threshold detect access_code with up to threshold bits wrong (-1 -> use default)
+		@param threshold detect access_code with up to threshold bits wrong (0 -> use default)
+		@param callback a function of args: ok, payload
 		"""
-		#setup
-		self._item_size_out = item_size_out
 		#access code
 		if not access_code: #get access code
 			access_code = packet_utils.default_access_code
@@ -164,29 +155,89 @@ class packet_decoder(gr.hier_block2):
 		if threshold < 0: threshold = DEFAULT_THRESHOLD
 		self._threshold = threshold
 		#blocks
-		self._msgq_in = gr.msg_queue(DEFAULT_MSGQ_LIMIT) #holds packets from the PHY
+		msgq = gr.msg_queue(DEFAULT_MSGQ_LIMIT) #holds packets from the PHY
 		correlator = gr.correlate_access_code_bb(self._access_code, self._threshold)
-		framer_sink = gr.framer_sink_1(self._msgq_in)
-		msg_source = gr.message_source(self._item_size_out, DEFAULT_MSGQ_LIMIT)
-		self._msgq_out = msg_source.msgq()
+		framer_sink = gr.framer_sink_1(msgq)
 		#initialize hier2
 		gr.hier_block2.__init__(
 			self,
 			"packet_decoder",
 			gr.io_signature(1, 1, gr.sizeof_char), # Input signature
-			gr.io_signature(1, 1, self._item_size_out) # Output signature
+			gr.io_signature(0, 0, 0) # Output signature
 		)
 		#connect
 		self.connect(self, correlator, framer_sink)
-		self.connect(msg_source, self)
 		#start thread
-		_packet_decoder_thread(self._msgq_in, self._recv_packet)
+		_packet_decoder_thread(msgq, callback)
 
-	def _recv_packet(self, ok, payload):
-		"""
-		Extract the payload from the packet and push onto message queue.
-		@param ok boolean ok
-		@param payload data received
-		"""
+##################################################
+## Packet Mod for OFDM Mod and Packet Encoder
+##################################################
+class packet_mod_base(gr.hier_block2):
+	"""
+	Hierarchical block for wrapping packet source block.
+	"""
+
+	def __init__(self, packet_source=None, payload_length=0):
+		if not payload_length: #get payload length
+			payload_length = DEFAULT_PAYLOAD_LEN
+		if payload_length%self._item_size_in != 0:	#verify that packet length is a multiple of the stream size
+			raise ValueError, 'The payload length: "%d" is not a mutiple of the stream size: "%d".'%(payload_length, self._item_size_in)
+		#initialize hier2
+		gr.hier_block2.__init__(
+			self,
+			"ofdm_mod",
+			gr.io_signature(1, 1, self._item_size_in), # Input signature
+			gr.io_signature(1, 1, packet_source._hb.output_signature().sizeof_stream_item(0)) # Output signature
+		)
+		#create blocks
+		msgq = gr.msg_queue(DEFAULT_MSGQ_LIMIT)
+		msg_sink = gr.message_sink(self._item_size_in, msgq, False) #False -> blocking
+		copy = gr.kludge_copy(packet_source._hb.output_signature().sizeof_stream_item(0))
+		#connect
+		self.connect(self, msg_sink)
+		self.connect(packet_source, copy, self)
+		#start thread
+		_packet_encoder_thread(msgq, payload_length, packet_source.send_pkt)
+
+class packet_mod_b(packet_mod_base): _item_size_in = gr.sizeof_char
+class packet_mod_s(packet_mod_base): _item_size_in = gr.sizeof_short
+class packet_mod_i(packet_mod_base): _item_size_in = gr.sizeof_int
+class packet_mod_f(packet_mod_base): _item_size_in = gr.sizeof_float
+class packet_mod_c(packet_mod_base): _item_size_in = gr.sizeof_gr_complex
+
+##################################################
+## Packet Demod for OFDM Demod and Packet Decoder
+##################################################
+class packet_demod_base(gr.hier_block2):
+	"""
+	Hierarchical block for wrapping packet sink block.
+	"""
+
+	def __init__(self, packet_sink=None):
+		#initialize hier2
+		gr.hier_block2.__init__(
+			self,
+			"ofdm_mod",
+			gr.io_signature(1, 1, packet_sink._hb.input_signature().sizeof_stream_item(0)), # Input signature
+			gr.io_signature(1, 1, self._item_size_out) # Output signature
+		)
+		#create blocks
+		msg_source = gr.message_source(self._item_size_out, DEFAULT_MSGQ_LIMIT)
+		self._msgq_out = msg_source.msgq()
+		copy = gr.kludge_copy(packet_sink._hb.input_signature().sizeof_stream_item(0))
+		#connect
+		self.connect(self, copy, packet_sink)
+		self.connect(msg_source, self)
+		if packet_sink._hb.output_signature().sizeof_stream_item(0):
+			self.connect(packet_sink, gr.null_sink(packet_sink._hb.output_signature().sizeof_stream_item(0)))
+
+	def recv_pkt(self, ok, payload):
 		msg = gr.message_from_string(payload, 0, self._item_size_out, len(payload)/self._item_size_out)
 		if ok: self._msgq_out.insert_tail(msg)
+
+class packet_demod_b(packet_demod_base): _item_size_out = gr.sizeof_char
+class packet_demod_s(packet_demod_base): _item_size_out = gr.sizeof_short
+class packet_demod_i(packet_demod_base): _item_size_out = gr.sizeof_int
+class packet_demod_f(packet_demod_base): _item_size_out = gr.sizeof_float
+class packet_demod_c(packet_demod_base): _item_size_out = gr.sizeof_gr_complex
diff --git a/grc/todo.txt b/grc/todo.txt
index 845430d9d..904128872 100644
--- a/grc/todo.txt
+++ b/grc/todo.txt
@@ -1,7 +1,6 @@
 ##################################################
 # Blocks
 ##################################################
--ofdm wrappers
 -probe: also non-float outputs
 -log slider gui control