l1/conv: Add convolutional coding primitives

As described in GMR-1 05.003 Section 4.4

Signed-off-by: Sylvain Munaut <tnt@246tNt.com>

1 files changed, 144 insertions, 0 deletions

diff --git a/src/l1/conv.c b/src/l1/conv.c
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+++ b/src/l1/conv.c
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+/* GMR-1 convolutional coding */
+/* See GMR-1 05.003 (ETSI TS 101 376-5-3 V1.2.1) - Section 4.4 */
+
+/* (C) 2011 by 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 Affero 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*! \addtogroup conv
+ *  @{
+ */
+
+/*! \file conv.c
+ *  \file Osmocom GMR-1 convolutional coding implementation
+ */
+
+#include <stdint.h>
+
+#include <osmocom/core/conv.h>
+
+
+/* All codes are K=5 and share the same next_state table */
+static const uint8_t gmr1_conv_next_state[][2] = {
+	{  0,  1 }, {  2,  3 }, {  4,  5 }, {  6,  7 },
+	{  8,  9 }, { 10, 11 }, { 12, 13 }, { 14, 15 },
+	{  0,  1 }, {  2,  3 }, {  4,  5 }, {  6,  7 },
+	{  8,  9 }, { 10, 11 }, { 12, 13 }, { 14, 15 },
+};
+
+
+/*
+ * GMR-1 Rate 1/2 convolutional code
+ *
+ * g0(D) = 1 +           D^3 + D^4
+ * g1(D) = 1 + D + D^2 +       D^4
+ */
+
+static const uint8_t gmr1_conv_12_next_output[][2] = {
+	{ 0, 3 }, { 1, 2 }, { 1, 2 }, { 0, 3 },
+	{ 2, 1 }, { 3, 0 }, { 3, 0 }, { 2, 1 },
+	{ 3, 0 }, { 2, 1 }, { 2, 1 }, { 3, 0 },
+	{ 1, 2 }, { 0, 3 }, { 0, 3 }, { 1, 2 },
+};
+
+/*! \brief GMR-1 rate 1/2 convolutional code */
+const struct osmo_conv_code gmr1_conv_12 = {
+	.N = 2,
+	.K = 5,
+	.len = 0, /* to be filled during specialization */
+	.next_output = gmr1_conv_12_next_output,
+	.next_state = gmr1_conv_next_state,
+};
+
+
+/*
+ * GMR-1 Rate 1/3 convolutional code
+ *
+ * g0(D) = 1 +     D^2 +       D^4
+ * g1(D) = 1 + D +       D^3 + D^4
+ * g2(D) = 1 + D + D^2 + D^3 + D^4
+ */
+
+static const uint8_t gmr1_conv_13_next_output[][2] = {
+	{ 0, 7 }, { 3, 4 }, { 5, 2 }, { 6, 1 },
+	{ 3, 4 }, { 0, 7 }, { 6, 1 }, { 5, 2 },
+	{ 7, 0 }, { 4, 3 }, { 2, 5 }, { 1, 6 },
+	{ 4, 3 }, { 7, 0 }, { 1, 6 }, { 2, 5 },
+};
+
+/*! \brief GMR-1 rate 1/3 convolutional code */
+const struct osmo_conv_code gmr1_conv_13 = {
+	.N = 3,
+	.K = 5,
+	.len = 0, /* to be filled during specialization */
+	.next_output = gmr1_conv_13_next_output,
+	.next_state = gmr1_conv_next_state,
+};
+
+
+/*
+ * GMR-1 Rate 1/4 convolutional code
+ *
+ * g0(D) = 1 +           D^3 + D^4
+ * g1(D) = 1 + D + D^2 +       D^4
+ * g2(D) = 1 +     D^2 +       D^4
+ * g3(D) = 1 + D + D^2 + D^3 + D^4
+ */
+
+static const uint8_t gmr1_conv_14_next_output[][2] = {
+	{  0, 15 }, {  5, 10 }, {  7,  8 }, {  2, 13 },
+	{  9,  6 }, { 12,  3 }, { 14,  1 }, { 11,  4 },
+	{ 15,  0 }, { 10,  5 }, {  8,  7 }, { 13,  2 },
+	{  6,  9 }, {  3, 12 }, {  1, 14 }, {  4, 11 },
+};
+
+/*! \brief GMR-1 rate 1/4 convolutional code */
+const struct osmo_conv_code gmr1_conv_14 = {
+	.N = 4,
+	.K = 5,
+	.len = 0, /* to be filled during specialization */
+	.next_output = gmr1_conv_14_next_output,
+	.next_state = gmr1_conv_next_state,
+};
+
+
+/*
+ * GMR-1 Rate 1/5 convolutional code
+ *
+ * g0(D) = 1 +     D^2 +       D^4
+ * g1(D) = 1 + D +       D^3 + D^4
+ * g2(D) = 1 + D + D^2 + D^3 + D^4
+ * g3(D) = 1 +     D^2 + D^3 + D^4
+ * g4(D) = 1 + D + D^2 +       D^4
+ */
+
+static const uint8_t gmr1_conv_15_next_output[][2] = {
+	{  0, 31 }, { 13, 18 }, { 23,  8 }, { 26,  5 },
+	{ 14, 17 }, {  3, 28 }, { 25,  6 }, { 20, 11 },
+	{ 31,  0 }, { 18, 13 }, {  8, 23 }, {  5, 26 },
+	{ 17, 14 }, { 28,  3 }, {  6, 25 }, { 11, 20 },
+};
+
+/*! \brief GMR-1 rate 1/5 convolutional code */
+const struct osmo_conv_code gmr1_conv_15 = {
+	.N = 5,
+	.K = 5,
+	.len = 0, /* to be filled during specialization */
+	.next_output = gmr1_conv_15_next_output,
+	.next_state = gmr1_conv_next_state,
+};
+
+/*! }@ */