diff --git a/include/osmocom/core/Makefile.am b/include/osmocom/core/Makefile.am
index 6109f47..b21e047 100644
--- a/include/osmocom/core/Makefile.am
+++ b/include/osmocom/core/Makefile.am
@@ -3,7 +3,7 @@
 		   gsmtap.h write_queue.h \
 		   logging.h rate_ctr.h gsmtap_util.h \
 		   plugin.h crc16.h panic.h process.h msgfile.h \
-		   backtrace.h
+		   backtrace.h conv.h
 
 if ENABLE_TALLOC
 osmocore_HEADERS += talloc.h
diff --git a/include/osmocom/core/conv.h b/include/osmocom/core/conv.h
new file mode 100644
index 0000000..af676ee
--- /dev/null
+++ b/include/osmocom/core/conv.h
@@ -0,0 +1,101 @@
+/*
+ * conv.h
+ *
+ * Copyright (C) 2011  Sylvain Munaut <tnt@246tNt.com>
+ *
+ * All Rights Reserved
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef __OSMO_CONV_H__
+#define __OSMO_CONV_H__
+
+#include <stdint.h>
+
+#include <osmocom/core/bits.h>
+
+struct osmo_conv_code {
+	int N;
+	int K;
+	int len;
+
+	const uint8_t (*next_output)[2];
+	const uint8_t (*next_state)[2];
+
+	const uint8_t *next_term_output;
+	const uint8_t *next_term_state;
+
+	const int *puncture;
+};
+
+
+/* Encoding */
+
+	/* Low level API */
+struct osmo_conv_encoder {
+	const struct osmo_conv_code *code;
+	int i_idx;	/* Next input bit index */
+	int p_idx;	/* Current puncture index */
+	uint8_t state;	/* Current state */
+};
+
+void osmo_conv_encode_init(struct osmo_conv_encoder *encoder,
+                           const struct osmo_conv_code *code);
+int  osmo_conv_encode_raw(struct osmo_conv_encoder *encoder,
+                          const ubit_t *input, ubit_t *output, int n);
+int  osmo_conv_encode_finish(struct osmo_conv_encoder *encoder, ubit_t *output);
+
+	/* All-in-one */
+int  osmo_conv_encode(const struct osmo_conv_code *code,
+                      const ubit_t *input, ubit_t *output);
+
+
+/* Decoding */
+
+	/* Low level API */
+struct osmo_conv_decoder {
+	const struct osmo_conv_code *code;
+
+	int n_states;
+
+	int len;		/* Max o_idx (excl. termination) */
+
+	int o_idx;		/* output index */
+	int p_idx;		/* puncture index */
+
+	unsigned int *ae;	/* accumulater error */
+	unsigned int *ae_next;	/* next accumulated error (tmp in scan) */
+	uint8_t *state_history;	/* state history [len][n_states] */
+};
+
+void osmo_conv_decode_init(struct osmo_conv_decoder *decoder,
+                           const struct osmo_conv_code *code, int len);
+void osmo_conv_decode_reset(struct osmo_conv_decoder *decoder);
+void osmo_conv_decode_deinit(struct osmo_conv_decoder *decoder);
+
+int osmo_conv_decode_scan(struct osmo_conv_decoder *decoder,
+                          const sbit_t *input, int n);
+int osmo_conv_decode_finish(struct osmo_conv_decoder *decoder,
+                            const sbit_t *input);
+int osmo_conv_decode_get_output(struct osmo_conv_decoder *decoder,
+                                ubit_t *output, int has_finish);
+
+	/* All-in-one */
+int osmo_conv_decode(const struct osmo_conv_code *code,
+                     const sbit_t *input, ubit_t *output);
+
+
+#endif /* __OSMO_CONV_H__ */
diff --git a/src/Makefile.am b/src/Makefile.am
index c5c8a21..a0d639c 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -14,7 +14,7 @@
 			 write_queue.c utils.c \
 			 logging.c logging_syslog.c rate_ctr.c \
 			 gsmtap_util.c crc16.c panic.c backtrace.c \
-			 process.c
+			 process.c conv.c
 
 if ENABLE_PLUGIN
 libosmocore_la_SOURCES += plugin.c
diff --git a/src/conv.c b/src/conv.c
new file mode 100644
index 0000000..cf820a3
--- /dev/null
+++ b/src/conv.c
@@ -0,0 +1,493 @@
+/*
+ * conv.c
+ *
+ * Generic convolutional encoding / decoding
+ *
+ * Copyright (C) 2011  Sylvain Munaut <tnt@246tNt.com>
+ *
+ * All Rights Reserved
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <alloca.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <osmocom/core/bits.h>
+#include <osmocom/core/conv.h>
+
+
+/* ------------------------------------------------------------------------ */
+/* Encoding                                                                 */
+/* ------------------------------------------------------------------------ */
+
+void
+osmo_conv_encode_init(struct osmo_conv_encoder *encoder,
+                      const struct osmo_conv_code *code)
+{
+	memset(encoder, 0x00, sizeof(struct osmo_conv_encoder));
+	encoder->code = code;
+}
+
+static inline int
+_conv_encode_do_output(struct osmo_conv_encoder *encoder,
+                       uint8_t out, ubit_t *output)
+{
+	const struct osmo_conv_code *code = encoder->code;
+	int o_idx = 0;
+	int j;
+
+	if (code->puncture) {
+		for (j=0; j<code->N; j++)
+		{
+			int bit_no = code->N - j - 1;
+			int r_idx = encoder->i_idx * code->N + j;
+
+			if (code->puncture[encoder->p_idx] == r_idx)
+				encoder->p_idx++;
+			else
+				output[o_idx++] = (out >> bit_no) & 1;
+		}
+	} else {
+		for (j=0; j<code->N; j++)
+		{
+			int bit_no = code->N - j - 1;
+			output[o_idx++] = (out >> bit_no) & 1;
+		}
+	}
+
+	return o_idx;
+}
+
+int
+osmo_conv_encode_raw(struct osmo_conv_encoder *encoder,
+                     const ubit_t *input, ubit_t *output, int n)
+{
+	const struct osmo_conv_code *code = encoder->code;
+	uint8_t state;
+	int i;
+	int o_idx;
+
+	o_idx = 0;
+	state = encoder->state;
+
+	for (i=0; i<n; i++) {
+		int bit = input[i];
+		uint8_t out;
+
+		out   = code->next_output[state][bit];
+		state = code->next_state[state][bit];
+
+		o_idx += _conv_encode_do_output(encoder, out, &output[o_idx]);
+
+		encoder->i_idx++;
+	}
+
+	encoder->state = state;
+
+	return o_idx;
+}
+
+int
+osmo_conv_encode_finish(struct osmo_conv_encoder *encoder,
+                        ubit_t *output)
+{
+	const struct osmo_conv_code *code = encoder->code;
+	uint8_t state;
+	int n;
+	int i;
+	int o_idx;
+
+	n = code->K - 1;
+
+	o_idx = 0;
+	state = encoder->state;
+
+	for (i=0; i<n; i++) {
+		uint8_t out;
+
+		if (code->next_term_output) {
+			out   = code->next_term_output[state];
+			state = code->next_term_state[state];
+		} else {
+			out   = code->next_output[state][0];
+			state = code->next_state[state][0];
+		}
+
+		o_idx += _conv_encode_do_output(encoder, out, &output[o_idx]);
+
+		encoder->i_idx++;
+	}
+
+	encoder->state = state;
+
+	return o_idx;
+}
+
+int
+osmo_conv_encode(const struct osmo_conv_code *code,
+                 const ubit_t *input, ubit_t *output)
+{
+	struct osmo_conv_encoder encoder;
+	int l;
+
+	osmo_conv_encode_init(&encoder, code);
+	l  = osmo_conv_encode_raw(&encoder, input, output, code->len);
+	l += osmo_conv_encode_finish(&encoder, &output[l]);
+
+	return l;
+}
+
+
+/* ------------------------------------------------------------------------ */
+/* Decoding (viterbi)                                                       */
+/* ------------------------------------------------------------------------ */
+
+#define MAX_AE 0x00ffffff
+
+void
+osmo_conv_decode_init(struct osmo_conv_decoder *decoder,
+                      const struct osmo_conv_code *code, int len)
+{
+	int n_states;
+
+	/* Init */
+	if (len <= 0)
+		len =  code->len;
+
+	n_states = 1 << (code->K - 1);
+
+	memset(decoder, 0x00, sizeof(struct osmo_conv_decoder));
+
+	decoder->code = code;
+	decoder->n_states = n_states;
+	decoder->len = len;
+
+	/* Allocate arrays */
+	decoder->ae      = malloc(sizeof(unsigned int) * n_states);
+	decoder->ae_next = malloc(sizeof(unsigned int) * n_states);
+
+	decoder->state_history = malloc(sizeof(uint8_t) * n_states * (len + decoder->code->K - 1));
+
+	/* Classic reset */
+	osmo_conv_decode_reset(decoder);
+}
+
+void
+osmo_conv_decode_reset(struct osmo_conv_decoder *decoder)
+{
+	int i;
+
+	/* Reset indexes */
+	decoder->o_idx = 0;
+	decoder->p_idx = 0;
+
+	/* Initial error (only state 0 is valid) */
+	decoder->ae[0] = 0;
+	for (i=1; i<decoder->n_states; i++) {
+		decoder->ae[i] = MAX_AE;
+	}
+}
+
+void
+osmo_conv_decode_deinit(struct osmo_conv_decoder *decoder)
+{
+	free(decoder->ae);
+	free(decoder->ae_next);
+	free(decoder->state_history);
+
+	memset(decoder, 0x00, sizeof(struct osmo_conv_decoder));
+}
+
+int
+osmo_conv_decode_scan(struct osmo_conv_decoder *decoder,
+                      const sbit_t *input, int n)
+{
+	const struct osmo_conv_code *code = decoder->code;
+
+	int i, s, b, j;
+
+	int n_states;
+	unsigned int *ae;
+	unsigned int *ae_next;
+	uint8_t *state_history;
+	sbit_t *in_sym;
+
+	int i_idx, p_idx;
+
+	/* Prepare */
+	n_states = decoder->n_states;
+
+	ae      = decoder->ae;
+	ae_next = decoder->ae_next;
+	state_history = &decoder->state_history[n_states * decoder->o_idx];
+
+	in_sym  = alloca(sizeof(sbit_t) * code->N);
+
+	i_idx = 0;
+	p_idx = decoder->p_idx;
+
+	/* Scan the treillis */
+	for (i=0; i<n; i++)
+	{
+		/* Reset next accumulated error */
+		for (s=0; s<n_states; s++) {
+			ae_next[s] = MAX_AE;
+		}
+
+		/* Get input */
+		if (code->puncture) {
+			/* Hard way ... */
+			for (j=0; j<code->N; j++) {
+				int idx = ((decoder->o_idx + i) * code->N) + j;
+				if (idx == code->puncture[p_idx]) {
+					in_sym[j] = 0;	/* Undefined */
+					p_idx++;
+				} else {
+					in_sym[j] = input[i_idx];
+					i_idx++;
+				}
+			}
+		} else {
+			/* Easy, just copy N bits */
+			memcpy(in_sym, &input[i_idx], code->N);
+			i_idx += code->N;
+		}
+
+		/* Scan all state */
+		for (s=0; s<n_states; s++)
+		{
+			/* Scan possible input bits */
+			for (b=0; b<2; b++)
+			{
+				int nae, ov, e;
+				uint8_t m;
+
+				/* Next output and state */
+				uint8_t out   = code->next_output[s][b];
+				uint8_t state = code->next_state[s][b];
+
+				/* New error for this path */
+				nae = ae[s];			/* start from last error */
+				m = 1 << (code->N - 1);		/* mask for 'out' bit selection */
+
+				for (j=0; j<code->N; j++) {
+					ov = (out & m) ? -127 : 127; /* sbit_t value for it */
+					e = ((int)in_sym[j]) - ov;   /* raw error for this bit */
+					nae += (e * e) >> 9;         /* acc the squared/scaled value */
+					m >>= 1;                     /* next mask bit */
+				}
+
+				/* Is it survivor ? */
+				if (ae_next[state] > nae) {
+					ae_next[state] = nae;
+					state_history[(n_states * i) + state] = s;
+				}
+			}
+		}
+
+		/* Copy accumulated error */
+		memcpy(ae, ae_next, sizeof(unsigned int) * n_states);
+	}
+
+	/* Update decoder state */
+	decoder->p_idx = p_idx;
+	decoder->o_idx += n;
+
+	return i_idx;
+}
+
+int
+osmo_conv_decode_finish(struct osmo_conv_decoder *decoder,
+                        const sbit_t *input)
+{
+	const struct osmo_conv_code *code = decoder->code;
+
+	int i, s, j;
+
+	int n_states;
+	unsigned int *ae;
+	unsigned int *ae_next;
+	uint8_t *state_history;
+	sbit_t *in_sym;
+
+	int i_idx, p_idx;
+
+	/* Prepare */
+	n_states = decoder->n_states;
+
+	ae      = decoder->ae;
+	ae_next = decoder->ae_next;
+	state_history = &decoder->state_history[n_states * decoder->o_idx];
+
+	in_sym  = alloca(sizeof(sbit_t) * code->N);
+
+	i_idx = 0;
+	p_idx = decoder->p_idx;
+
+	/* Scan the treillis */
+	for (i=0; i<code->K-1; i++)
+	{
+		/* Reset next accumulated error */
+		for (s=0; s<n_states; s++) {
+			ae_next[s] = MAX_AE;
+		}
+
+		/* Get input */
+		if (code->puncture) {
+			/* Hard way ... */
+			for (j=0; j<code->N; j++) {
+				int idx = ((decoder->o_idx + i) * code->N) + j;
+				if (idx == code->puncture[p_idx]) {
+					in_sym[j] = 0;	/* Undefined */
+					p_idx++;
+				} else {
+					in_sym[j] = input[i_idx];
+					i_idx++;
+				}
+			}
+		} else {
+			/* Easy, just copy N bits */
+			memcpy(in_sym, &input[i_idx], code->N);
+			i_idx += code->N;
+		}
+
+		/* Scan all state */
+		for (s=0; s<n_states; s++)
+		{
+			int nae, ov, e;
+			uint8_t m;
+
+			/* Next output and state */
+			uint8_t out;
+			uint8_t state;
+
+			if (code->next_term_output) {
+				out   = code->next_term_output[s];
+				state = code->next_term_state[s];
+			} else {
+				out   = code->next_output[s][0];
+				state = code->next_state[s][0];
+			}
+
+			/* New error for this path */
+			nae = ae[s];			/* start from last error */
+			m = 1 << (code->N - 1);		/* mask for 'out' bit selection */
+
+			for (j=0; j<code->N; j++) {
+				ov = (out & m) ? -127 : 127; /* sbit_t value for it */
+				e = ((int)in_sym[j]) - ov;   /* raw error for this bit */
+				nae += (e * e) >> 9;         /* acc the squared/scaled value */
+				m >>= 1;                     /* next mask bit */
+			}
+
+			/* Is it survivor ? */
+			if (ae_next[state] > nae) {
+				ae_next[state] = nae;
+				state_history[(n_states * i) + state] = s;
+			}
+		}
+
+		/* Copy accumulated error */
+		memcpy(ae, ae_next, sizeof(unsigned int) * n_states);
+	}
+
+	/* Update decoder state */
+	decoder->p_idx = p_idx;
+	decoder->o_idx += code->K - 1;
+
+	return i_idx;
+}
+
+int
+osmo_conv_decode_get_output(struct osmo_conv_decoder *decoder,
+                            ubit_t *output, int has_finish)
+{
+	const struct osmo_conv_code *code = decoder->code;
+
+	int min_ae;
+	uint8_t min_state, cur_state;
+	int i, s, n;
+
+	uint8_t *sh_ptr;
+
+	/* Find state with least error */
+	min_ae = MAX_AE;
+	min_state = 0xff;
+
+	for (s=0; s<decoder->n_states; s++)
+	{
+		if (decoder->ae[s] < min_ae) {
+			min_ae = decoder->ae[s];
+			min_state = s;
+		}
+	}
+
+	if (min_state == 0xff)
+		return -1;
+
+	/* Traceback */
+	cur_state = min_state;
+
+	n = decoder->o_idx;
+
+	sh_ptr = &decoder->state_history[decoder->n_states * (n-1)];
+
+		/* No output for the K-1 termination input bits */
+	if (has_finish) {
+		for (i=0; i<code->K-1; i++) {
+			cur_state = sh_ptr[cur_state];
+			sh_ptr -= decoder->n_states;
+		}
+		n -= code->K - 1;
+	}
+
+		/* Generate output backward */
+	for (i=n-1; i>=0; i--)
+	{
+		min_state = cur_state;
+		cur_state = sh_ptr[cur_state];
+
+		sh_ptr -= decoder->n_states;
+
+		if (code->next_state[cur_state][0] == min_state)
+			output[i] = 0;
+		else
+			output[i] = 1;
+	}
+
+	return min_ae;
+}
+
+int
+osmo_conv_decode(const struct osmo_conv_code *code,
+                 const sbit_t *input, ubit_t *output)
+{
+	struct osmo_conv_decoder decoder;
+	int rv, l;
+
+	osmo_conv_decode_init(&decoder, code, 0);
+
+	l = osmo_conv_decode_scan(&decoder, input, code->len);
+	l = osmo_conv_decode_finish(&decoder, &input[l]);
+
+	rv = osmo_conv_decode_get_output(&decoder, output, 1);
+
+	osmo_conv_decode_deinit(&decoder);
+
+	return rv;
+}