Start on the convolution FEC.

M17Control.cpp

@@ -156,18 +156,8 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 		m_rfLICH.reset();
 
 		CM17Convolution conv;
-		conv.start();
-
-		unsigned int n = 2U + M17_SYNC_LENGTH_BYTES;
-		for (unsigned int i = 0U; i < (M17_LICH_LENGTH_BYTES / 2U); i++) {
-			uint8_t s0 = data[n++];
-			uint8_t s1 = data[n++];
-
-			conv.decode(s0, s1);
-		}
-
 		unsigned char frame[M17_LICH_LENGTH_BYTES];
-		conv.chainback(frame, M17_LICH_LENGTH_BITS);
+		conv.decodeLinkSetup(data, frame);
 
 		bool valid = CM17CRC::checkCRC(frame, M17_LICH_LENGTH_BYTES);
 		if (valid) {
@@ -224,12 +214,9 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 				unsigned char setup[M17_LICH_LENGTH_BYTES];
 				m_rfLICH.getLinkSetup(data + 2U);
 
-				// Add the CRC
-				CM17CRC::encodeCRC(data + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
-
 				// Add the convolution FEC
 				CM17Convolution conv;
-				conv.encode(setup, data + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BITS + M17_CRC_LENGTH_BITS);
+				conv.encodeLinkSetup(setup, data + 2U + M17_SYNC_LENGTH_BYTES);
 
 				unsigned char temp[M17_FRAME_LENGTH_BYTES];
 				interleaver(data + 2U, temp);
@@ -244,18 +231,8 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 
 	if (m_rfState == RS_RF_LATE_ENTRY) {
 		CM17Convolution conv;
-		conv.start();
-
-		unsigned int n = 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_LENGTH_BYTES;
-		for (unsigned int i = 0U; i < (M17_LICH_LENGTH_BYTES / 2U); i++) {
-			uint8_t s0 = data[n++];
-			uint8_t s1 = data[n++];
-
-			conv.decode(s0, s1);
-		}
-
 		unsigned char frame[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES];
-		conv.chainback(frame, M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS + M17_CRC_LENGTH_BITS);
+		conv.decodeData(data, frame);
 
 		bool valid = CM17CRC::checkCRC(frame, M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
 		if (valid) {
@@ -322,12 +299,9 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 					unsigned char setup[M17_LICH_LENGTH_BYTES];
 					m_rfLICH.getLinkSetup(data + 2U);
 
-					// Add the CRC
-					CM17CRC::encodeCRC(data + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
-
 					// Add the convolution FEC
 					CM17Convolution conv;
-					conv.encode(setup, data + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BITS + M17_CRC_LENGTH_BITS);
+					conv.encodeLinkSetup(setup, data + 2U + M17_SYNC_LENGTH_BYTES);
 
 					unsigned char temp[M17_FRAME_LENGTH_BYTES];
 					interleaver(data + 2U, temp);
@@ -344,18 +318,8 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 		writeFile(data + 2U);
 #endif
 		CM17Convolution conv;
-		conv.start();
-
-		unsigned int n = 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_LENGTH_BYTES;
-		for (unsigned int i = 0U; i < ((M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES) / 2U); i++) {
-			uint8_t s0 = data[n++];
-			uint8_t s1 = data[n++];
-
-			conv.decode(s0, s1);
-		}
-
 		unsigned char frame[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES];
-		conv.chainback(frame, M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS + M17_CRC_LENGTH_BITS);
+		conv.decodeData(data, frame);
 
 		bool valid = CM17CRC::checkCRC(frame, M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
 		if (valid) {
@@ -399,7 +363,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 		// XXX TODO Golay on LICH fragment
 
 		// Re-encode the payload
-		conv.encode(frame, rfData + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_LENGTH_BYTES, M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS + M17_CRC_LENGTH_BITS);
+		conv.encodeData(frame, rfData + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_LENGTH_BYTES);
 
 		// Calculate the BER
 		if (valid) {
@@ -551,12 +515,9 @@ void CM17Control::writeNetwork()
 		unsigned char setup[M17_LICH_LENGTH_BYTES];
 		m_netLICH.getLinkSetup(start + 2U);
 
-		// Add the CRC
-		CM17CRC::encodeCRC(start + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BYTES + M17_CRC_LENGTH_BYTES);
-
 		// Add the convolution FEC
 		CM17Convolution conv;
-		conv.encode(setup, start + 2U + M17_SYNC_LENGTH_BYTES, M17_LICH_LENGTH_BITS + M17_CRC_LENGTH_BITS);
+		conv.encodeLinkSetup(setup, start + 2U + M17_SYNC_LENGTH_BYTES);
 
 		unsigned char temp[M17_FRAME_LENGTH_BYTES];
 		interleaver(start + 2U, temp);
@@ -616,7 +577,7 @@ void CM17Control::writeNetwork()
 
 	// Add the Convolution FEC
 	CM17Convolution conv;
-	conv.encode(payload, p, M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS + M17_CRC_LENGTH_BITS);
+	conv.encodeData(payload, p);
 
 	unsigned char temp[M17_FRAME_LENGTH_BYTES];
 	interleaver(data + 2U, temp);

M17Convolution.cpp

@@ -0,0 +1,276 @@
+/*
+ *   Copyright (C) 2009-2016,2018 by Jonathan Naylor G4KLX
+ *
+ *   This program 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 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include "M17Convolution.h"
+
+#include <cstdio>
+#include <cassert>
+#include <cstring>
+#include <cstdlib>
+
+const unsigned int PUNCTURE_LIST_LINK_SETUP[] = { 3U,  11U,  17U,  25U,  31U,  39U,  45U,  53U,  59U,  67U,
+									  73U,  81U,  87U,  95U, 101U, 109U, 115U, 123U, 129U, 137U,
+									 143U, 151U, 157U, 165U, 171U, 179U, 185U, 193U, 199U, 207U,
+									 213U, 221U, 227U, 235U, 241U, 249U, 255U, 263U, 269U, 277U,
+									 283U, 291U, 297U, 305U, 311U, 319U, 325U, 333U, 339U, 347U,
+									 353U, 361U, 367U, 375U, 381U, 389U, 395U, 403U };
+
+const unsigned int PUNCTURE_LIST_DATA[] = { 3U,  11U,  17U,  25U,  31U,  39U,  45U,  53U,  59U,  67U,
+									  73U,  81U,  87U,  95U, 101U, 109U, 115U, 123U, 129U, 137U,
+									 143U, 151U, 157U, 165U, 171U, 179U, 185U, 193U, 199U, 207U,
+									 213U, 221U, 227U, 235U, 241U, 249U, 255U, 263U, 269U, 277U,
+									 283U, 291U, 297U, 305U, 311U, 319U, 325U, 333U, 339U, 347U,
+									 353U, 361U, 367U, 375U, 381U, 389U, 395U, 403U };
+
+const unsigned char BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U};
+
+#define WRITE_BIT1(p,i,b) p[(i)>>3] = (b) ? (p[(i)>>3] | BIT_MASK_TABLE[(i)&7]) : (p[(i)>>3] & ~BIT_MASK_TABLE[(i)&7])
+#define READ_BIT1(p,i)    (p[(i)>>3] & BIT_MASK_TABLE[(i)&7])
+
+const uint8_t BRANCH_TABLE1[] = {0U, 0U, 0U, 0U, 2U, 2U, 2U, 2U};
+const uint8_t BRANCH_TABLE2[] = {0U, 2U, 2U, 0U, 0U, 2U, 2U, 0U};
+
+const unsigned int NUM_OF_STATES_D2 = 8U;
+const unsigned int NUM_OF_STATES = 16U;
+const uint32_t     M = 4U;
+const unsigned int K = 5U;
+
+CM17Convolution::CM17Convolution() :
+m_metrics1(NULL),
+m_metrics2(NULL),
+m_oldMetrics(NULL),
+m_newMetrics(NULL),
+m_decisions(NULL),
+m_dp(NULL)
+{
+	m_metrics1  = new uint16_t[16U];
+	m_metrics2  = new uint16_t[16U];
+	m_decisions = new uint64_t[300U];
+}
+
+CM17Convolution::~CM17Convolution()
+{
+	delete[] m_metrics1;
+	delete[] m_metrics2;
+	delete[] m_decisions;
+}
+
+void CM17Convolution::encodeLinkSetup(const unsigned char* in, unsigned char* out) const
+{
+	assert(in != NULL);
+	assert(out != NULL);
+
+	unsigned char temp1[31U];
+	::memset(temp1, 0x00U, 31U);
+	::memcpy(temp1, in, 30U);
+
+	unsigned char temp2[61U];
+	encode(temp1, temp2, 244U);
+
+	unsigned int n = 0U;
+	unsigned int index = 0U;
+	for (unsigned int i = 0U; i < 488U; i++) {
+		if (i != PUNCTURE_LIST_LINK_SETUP[index]) {
+			bool b = READ_BIT1(temp2, i);
+			WRITE_BIT1(out, n, b);
+			n++;
+		} else {
+			index++;
+		}
+	}
+}
+
+void CM17Convolution::encodeData(const unsigned char* in, unsigned char* out) const
+{
+	assert(in != NULL);
+	assert(out != NULL);
+
+	unsigned char temp1[21U];
+	::memset(temp1, 0x00U, 21U);
+	::memcpy(temp1, in, 20U);
+
+	unsigned char temp2[41U];
+	encode(temp1, temp2, 164U);
+
+	unsigned int n = 0U;
+	unsigned int index = 0U;
+	for (unsigned int i = 0U; i < 328U; i++) {
+		if (i != PUNCTURE_LIST_DATA[index]) {
+			bool b = READ_BIT1(temp2, i);
+			WRITE_BIT1(out, n, b);
+			n++;
+		} else {
+			index++;
+		}
+	}
+}
+
+void CM17Convolution::decodeLinkSetup(const unsigned char* in, unsigned char* out)
+{
+	assert(in != NULL);
+	assert(out != NULL);
+
+	uint8_t temp[488U];
+
+	unsigned int n = 0U;
+	unsigned int index = 0U;
+	for (unsigned int i = 0U; i < 368U; i++) {
+		if (n == PUNCTURE_LIST_LINK_SETUP[index]) {
+			temp[n++] = 1U;
+			index++;
+		}
+
+		bool b = READ_BIT1(in, i);
+		temp[n++] = b ? 2U : 0U;
+	}
+
+	for (unsigned int i = 0U; i < 8U; i++)
+		temp[n++] = 0U;
+
+	start();
+
+	n = 0U;
+	for (unsigned int i = 0U; i < 244U; i++) {
+		uint8_t s0 = temp[n++];
+		uint8_t s1 = temp[n++];
+
+		decode(s0, s1);
+	}
+
+	chainback(out, 244U);
+}
+
+void CM17Convolution::decodeData(const unsigned char* in, unsigned char* out)
+{
+	assert(in != NULL);
+	assert(out != NULL);
+
+	uint8_t temp[328U];
+
+	unsigned int n = 0U;
+	unsigned int index = 0U;
+	for (unsigned int i = 0U; i < 272U; i++) {
+		if (n == PUNCTURE_LIST_DATA[index]) {
+			temp[n++] = 1U;
+			index++;
+		}
+
+		bool b = READ_BIT1(in, i);
+		temp[n++] = b ? 2U : 0U;
+	}
+
+	for (unsigned int i = 0U; i < 8U; i++)
+		temp[n++] = 0U;
+
+	start();
+
+	n = 0U;
+	for (unsigned int i = 0U; i < 164U; i++) {
+		uint8_t s0 = temp[n++];
+		uint8_t s1 = temp[n++];
+
+		decode(s0, s1);
+	}
+
+	chainback(out, 164U);
+}
+
+void CM17Convolution::start()
+{
+	::memset(m_metrics1, 0x00U, NUM_OF_STATES * sizeof(uint16_t));
+	::memset(m_metrics2, 0x00U, NUM_OF_STATES * sizeof(uint16_t));
+
+	m_oldMetrics = m_metrics1;
+	m_newMetrics = m_metrics2;
+	m_dp = m_decisions;
+}
+
+void CM17Convolution::decode(uint8_t s0, uint8_t s1)
+{
+  *m_dp = 0U;
+
+  for (uint8_t i = 0U; i < NUM_OF_STATES_D2; i++) {
+    uint8_t j = i * 2U;
+
+    uint16_t metric = std::abs(BRANCH_TABLE1[i] - s0) + std::abs(BRANCH_TABLE2[i] - s1);
+
+    uint16_t m0 = m_oldMetrics[i] + metric;
+    uint16_t m1 = m_oldMetrics[i + NUM_OF_STATES_D2] + (M - metric);
+    uint8_t decision0 = (m0 >= m1) ? 1U : 0U;
+    m_newMetrics[j + 0U] = decision0 != 0U ? m1 : m0;
+
+    m0 = m_oldMetrics[i] + (M - metric);
+    m1 = m_oldMetrics[i + NUM_OF_STATES_D2] + metric;
+    uint8_t decision1 = (m0 >= m1) ? 1U : 0U;
+    m_newMetrics[j + 1U] = decision1 != 0U ? m1 : m0;
+
+    *m_dp |= (uint64_t(decision1) << (j + 1U)) | (uint64_t(decision0) << (j + 0U));
+  }
+
+  ++m_dp;
+
+  assert((m_dp - m_decisions) <= 300);
+
+  uint16_t* tmp = m_oldMetrics;
+  m_oldMetrics = m_newMetrics;
+  m_newMetrics = tmp;
+}
+
+void CM17Convolution::chainback(unsigned char* out, unsigned int nBits)
+{
+	assert(out != NULL);
+
+	uint32_t state = 0U;
+
+	while (nBits-- > 0) {
+		--m_dp;
+
+		uint32_t  i = state >> (9 - K);
+		uint8_t bit = uint8_t(*m_dp >> i) & 1;
+		state = (bit << 7) | (state >> 1);
+
+		WRITE_BIT1(out, nBits, bit != 0U);
+	}
+}
+
+void CM17Convolution::encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const
+{
+	assert(in != NULL);
+	assert(out != NULL);
+	assert(nBits > 0U);
+
+	uint8_t d1 = 0U, d2 = 0U, d3 = 0U, d4 = 0U;
+	uint32_t k = 0U;
+	for (unsigned int i = 0U; i < nBits; i++) {
+		uint8_t d = READ_BIT1(in, i) ? 1U : 0U;
+
+		uint8_t g1 = (d + d3 + d4) & 1;
+		uint8_t g2 = (d + d1 + d2 + d4) & 1;
+
+		d4 = d3;
+		d3 = d2;
+		d2 = d1;
+		d1 = d;
+
+		WRITE_BIT1(out, k, g1 != 0U);
+		k++;
+
+		WRITE_BIT1(out, k, g2 != 0U);
+		k++;
+	}
+}

M17Convolution.h

@@ -26,11 +26,11 @@ public:
 	CM17Convolution();
 	~CM17Convolution();
 
-	void start();
+	void decodeLinkSetup(const unsigned char* in, unsigned char* out);
-	void decode(uint8_t s0, uint8_t s1);
+	void decodeData(const unsigned char* in, unsigned char* out);
-	void chainback(unsigned char* out, unsigned int nBits);
 
-	void encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const;
+	void encodeLinkSetup(const unsigned char* in, unsigned char* out) const;
+	void encodeData(const unsigned char* in, unsigned char* out) const;
 
 private:
 	uint16_t* m_metrics1;
@@ -39,6 +39,12 @@ private:
 	uint16_t* m_newMetrics;
 	uint64_t* m_decisions;
 	uint64_t* m_dp;
+
+	void start();
+	void decode(uint8_t s0, uint8_t s1);
+	void chainback(unsigned char* out, unsigned int nBits);
+
+	void encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const;
 };
 
 #endif

M17LICH.cpp

@@ -22,17 +22,6 @@
 
 #include <cassert>
 
-CM17LICH::CM17LICH(const CM17LICH& lich) :
-m_lich(NULL),
-m_valid(false)
-{
-	m_lich = new unsigned char[30U];
-
-	::memcpy(m_lich, lich.m_lich, 30U);
-
-	m_valid = lich.m_valid;
-}
-
 CM17LICH::CM17LICH() :
 m_lich(NULL),
 m_valid(false)

M17LICH.h

@@ -23,7 +23,6 @@
 
 class CM17LICH {
 public:
-	CM17LICH(const CM17LICH& lich);
 	CM17LICH();
 	~CM17LICH();
 
@@ -48,8 +47,6 @@ public:
 	void getFragment(unsigned char* data, unsigned short fn) const;
 	void setFragment(const unsigned char* data, unsigned short fn);
 
-	CM17LICH& operator=(const CM17LICH& lich);
-
 private:
 	unsigned char* m_lich;
 	bool           m_valid;

MMDVMHost.vcxproj

@@ -291,6 +291,7 @@
     <ClCompile Include="LCDproc.cpp" />
     <ClCompile Include="Log.cpp" />
     <ClCompile Include="M17Control.cpp" />
+    <ClCompile Include="M17Convolution.cpp" />
     <ClCompile Include="M17CRC.cpp" />
     <ClCompile Include="M17LICH.cpp" />
     <ClCompile Include="M17Network.cpp" />

MMDVMHost.vcxproj.filters

@@ -598,5 +598,8 @@
     <ClCompile Include="M17LICH.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="M17Convolution.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
 </Project>