viterbi decoder: add viterbi decoder base class

Add a viterbi decoder base class that viterbi decoder implementations can inherit from.
2016-11-07 15:00:30 -05:00
parent 9cf628359b
commit 528536e3f2
7 changed files with 185 additions and 240 deletions
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2016 Bastian Bloessl <bloessl@ccs-labs.org>
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef INCLUDED_IEEE802_11_VITERBI_DECODER_BASE_H
+#define INCLUDED_IEEE802_11_VITERBI_DECODER_BASE_H
+
+#include "utils.h"
+
+namespace gr {
+namespace ieee802_11 {
+
+// Maximum number of traceback bytes
+#define TRACEBACK_MAX 24
+
+/* This Viterbi decoder was taken from the gr-dvbt module of
+ * GNU Radio. It is an SSE2 version of the Viterbi Decoder
+ * created by Phil Karn. The SSE2 version was made by Bogdan
+ * Diaconescu. For more info see: gr-dvbt/lib/d_viterbi.h
+ */
+class base
+{
+public:
+
+	base();
+	~base();
+	virtual uint8_t* decode(ofdm_param *ofdm, frame_param *frame, uint8_t *in) = 0;
+
+protected:
+	// Position in circular buffer where the current decoded byte is stored
+	int d_store_pos;
+	// Metrics for each state
+	unsigned char d_mmresult[64] __attribute__((aligned(16)));
+	// Paths for each state
+	unsigned char d_ppresult[TRACEBACK_MAX][64] __attribute__((aligned(16)));
+
+	int d_ntraceback;
+	int d_k;
+	ofdm_param *d_ofdm;
+	frame_param *d_frame;
+	const unsigned char *d_depuncture_pattern;
+
+	uint8_t d_depunctured[MAX_ENCODED_BITS];
+	uint8_t d_decoded[MAX_ENCODED_BITS * 3 / 4];
+
+	static const unsigned char PARTAB[256];
+	static const unsigned char PUNCTURE_1_2[2];
+	static const unsigned char PUNCTURE_2_3[4];
+	static const unsigned char PUNCTURE_3_4[6];
+
+	virtual void reset() = 0;
+	uint8_t* depuncture(uint8_t *in);
+};
+
+} // namespace ieee802_11
+} // namespace gr
+
+#endif /* INCLUDED_IEEE802_11_VITERBI_DECODER_BASE_H */