Osmocom Packet control Unit (PCU): Network-side GPRS (RLC/MAC); BTS- or BSC-colocated https://osmocom.org/projects/osmopcu
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osmo-pcu/src/coding_scheme.c

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/* coding_scheme.c
*
* Copyright (C) 2019 by sysmocom s.f.m.c. GmbH
*
* 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <stdint.h>
#include <stdbool.h>
#include <osmocom/core/utils.h>
#include "coding_scheme.h"
const struct value_string mcs_names[] = {
{ UNKNOWN, "UNKNOWN" },
{ CS1, "CS-1" },
{ CS2, "CS-2" },
{ CS3, "CS-3" },
{ CS4, "CS-4" },
{ MCS1, "MCS-1" },
{ MCS2, "MCS-2" },
{ MCS3, "MCS-3" },
{ MCS4, "MCS-4" },
{ MCS5, "MCS-5" },
{ MCS6, "MCS-6" },
{ MCS7, "MCS-7" },
{ MCS8, "MCS-8" },
{ MCS9, "MCS-9" },
{ 0, NULL }
};
enum Family {
FAMILY_INVALID,
FAMILY_A,
FAMILY_B,
FAMILY_C,
};
static struct {
struct {
uint8_t bytes;
uint8_t ext_bits;
uint8_t data_header_bits;
} uplink, downlink;
uint8_t data_bytes;
uint8_t optional_padding_bits;
enum HeaderType data_hdr;
enum Family family;
} mcs_info[NUM_SCHEMES] = {
{{0, 0}, {0, 0}, 0, 0,
HEADER_INVALID, FAMILY_INVALID},
{{23, 0}, {23, 0}, 20, 0,
HEADER_GPRS_DATA, FAMILY_INVALID},
{{33, 7}, {33, 7}, 30, 0,
HEADER_GPRS_DATA, FAMILY_INVALID},
{{39, 3}, {39, 3}, 36, 0,
HEADER_GPRS_DATA, FAMILY_INVALID},
{{53, 7}, {53, 7}, 50, 0,
HEADER_GPRS_DATA, FAMILY_INVALID},
{{26, 1}, {26, 1}, 22, 0,
HEADER_EGPRS_DATA_TYPE_3, FAMILY_C},
{{32, 1}, {32, 1}, 28, 0,
HEADER_EGPRS_DATA_TYPE_3, FAMILY_B},
{{41, 1}, {41, 1}, 37, 48,
HEADER_EGPRS_DATA_TYPE_3, FAMILY_A},
{{48, 1}, {48, 1}, 44, 0,
HEADER_EGPRS_DATA_TYPE_3, FAMILY_C},
{{60, 7}, {59, 6}, 56, 0,
HEADER_EGPRS_DATA_TYPE_2, FAMILY_B},
{{78, 7}, {77, 6}, 74, 48,
HEADER_EGPRS_DATA_TYPE_2, FAMILY_A},
{{118, 2}, {117, 4}, 56, 0,
HEADER_EGPRS_DATA_TYPE_1, FAMILY_B},
{{142, 2}, {141, 4}, 68, 0,
HEADER_EGPRS_DATA_TYPE_1, FAMILY_A},
{{154, 2}, {153, 4}, 74, 0,
HEADER_EGPRS_DATA_TYPE_1, FAMILY_A},
};
const char *mcs_name(enum CodingScheme val) {
return get_value_string(mcs_names, val);
}
bool mcs_is_gprs(enum CodingScheme cs)
{
return CS1 <= cs && cs <= CS4;
}
bool mcs_is_edge(enum CodingScheme cs)
{
return MCS1 <= cs && cs <= MCS9;
}
bool mcs_is_edge_gmsk(enum CodingScheme cs)
{
if (mcs_is_edge(cs))
return cs <= MCS4;
return false;
}
/* Return 3GPP TS 44.060 §12.10d (EDGE) or Table 11.2.28.2 (GPRS) Channel Coding Command value */
uint8_t mcs_chan_code(enum CodingScheme cs)
{
if (mcs_is_gprs(cs))
return cs - CS1;
if (mcs_is_edge(cs))
return cs - MCS1;
/* Defaults to (M)CS1 */
return 0;
}
enum CodingScheme mcs_get_by_size_ul(unsigned size)
{
switch (size) {
case 23: return CS1;
case 27: return MCS1;
case 33: return MCS2;
case 34: return CS2;
case 40: return CS3;
case 42: return MCS3;
case 49: return MCS4;
case 54: return CS4;
case 61: return MCS5;
case 79: return MCS6;
case 119: return MCS7;
case 143: return MCS8;
case 155: return MCS9;
default: return UNKNOWN;
}
}
enum CodingScheme mcs_get_gprs_by_num(unsigned num)
{
if (num < 1 || num > 4)
return UNKNOWN;
return CS1 + (num - 1);
}
enum CodingScheme mcs_get_egprs_by_num(unsigned num)
{
if (num < 1 || num > 9)
return UNKNOWN;
return MCS1 + (num - 1);
}
bool mcs_is_valid(enum CodingScheme cs)
{
return UNKNOWN < cs && cs <= MCS9;
}
bool mcs_is_compat_kind(enum CodingScheme cs, enum mcs_kind mode)
{
switch (mode) {
case GPRS: return mcs_is_gprs(cs);
case EGPRS_GMSK: return mcs_is_edge_gmsk(cs);
case EGPRS: return mcs_is_edge(cs);
}
return false;
}
bool mcs_is_compat(enum CodingScheme cs, enum CodingScheme o)
{
return (mcs_is_gprs(cs) && mcs_is_gprs(o)) || (mcs_is_edge(cs) && mcs_is_edge(o));
}
uint8_t mcs_size_ul(enum CodingScheme cs)
{
return mcs_info[cs].uplink.bytes + (mcs_spare_bits_ul(cs) ? 1 : 0);
}
uint8_t mcs_size_dl(enum CodingScheme cs)
{
return mcs_info[cs].downlink.bytes + (mcs_spare_bits_dl(cs) ? 1 : 0);
}
uint8_t mcs_used_size_ul(enum CodingScheme cs)
{
if (mcs_info[cs].data_hdr == HEADER_GPRS_DATA)
return mcs_info[cs].uplink.bytes;
else
return mcs_size_ul(cs);
}
uint8_t mcs_used_size_dl(enum CodingScheme cs)
{
if (mcs_info[cs].data_hdr == HEADER_GPRS_DATA)
return mcs_info[cs].downlink.bytes;
else
return mcs_size_dl(cs);
}
uint8_t mcs_max_bytes_ul(enum CodingScheme cs)
{
return mcs_info[cs].uplink.bytes;
}
uint8_t mcs_max_bytes_dl(enum CodingScheme cs)
{
return mcs_info[cs].downlink.bytes;
}
uint8_t mcs_spare_bits_ul(enum CodingScheme cs)
{
return mcs_info[cs].uplink.ext_bits;
}
uint8_t mcs_spare_bits_dl(enum CodingScheme cs)
{
return mcs_info[cs].downlink.ext_bits;
}
uint8_t mcs_max_data_block_bytes(enum CodingScheme cs)
{
return mcs_info[cs].data_bytes;
}
uint8_t mcs_opt_padding_bits(enum CodingScheme cs)
{
return mcs_info[cs].optional_padding_bits;
}
void mcs_inc_kind(enum CodingScheme *cs, enum mcs_kind mode)
{
if (!mcs_is_compat_kind(*cs, mode))
/* This should not happen. TODO: Use assert? */
return;
enum CodingScheme new_cs = *cs + 1;
if (!mcs_is_compat_kind(new_cs, mode))
/* Clipping, do not change the value */
return;
*cs = new_cs;
}
void mcs_dec_kind(enum CodingScheme *cs, enum mcs_kind mode)
{
if (!mcs_is_compat_kind(*cs, mode))
/* This should not happen. TODO: Use assert? */
return;
enum CodingScheme new_cs = *cs - 1;
if (!mcs_is_compat_kind(new_cs, mode))
/* Clipping, do not change the value */
return;
*cs = new_cs;
}
void mcs_inc(enum CodingScheme *cs)
{
if (mcs_is_gprs(*cs) && *cs == CS4)
return;
if (mcs_is_edge(*cs) && *cs == MCS9)
return;
if (!mcs_is_valid(*cs))
return;
*cs = *cs + 1;
}
void mcs_dec(enum CodingScheme *cs)
{
if (mcs_is_gprs(*cs) && *cs == CS1)
return;
if (mcs_is_edge(*cs) && *cs == MCS1)
return;
if (!mcs_is_valid(*cs))
return;
*cs = *cs - 1;
}
bool mcs_is_family_compat(enum CodingScheme cs, enum CodingScheme o)
{
if (cs == o)
return true;
if (mcs_info[cs].family == FAMILY_INVALID)
return false;
return mcs_info[cs].family == mcs_info[o].family;
}
void mcs_dec_to_single_block(enum CodingScheme *cs, bool *need_stuffing)
{
switch (*cs) {
case MCS7: *need_stuffing = false; *cs = MCS5; break;
case MCS8: *need_stuffing = true; *cs = MCS6; break;
case MCS9: *need_stuffing = false; *cs = MCS6; break;
default: *need_stuffing = false; break;
}
}
static struct {
struct {
uint8_t data_header_bits;
} uplink, downlink;
uint8_t data_block_header_bits;
uint8_t num_blocks;
const char *name;
} hdr_type_info[NUM_HEADER_TYPES] = {
{ { 0 }, { 0 }, 0, 0, "INVALID" },
{ { 1 * 8 + 0 }, { 1 * 8 + 0 }, 0, 0, "CONTROL" },
{ { 3 * 8 + 0 }, { 3 * 8 + 0 }, 0, 1, "GPRS_DATA" },
{ { 5 * 8 + 6 }, { 5 * 8 + 0 }, 2, 2, "EGPRS_DATA_TYPE1" },
{ { 4 * 8 + 5 }, { 3 * 8 + 4 }, 2, 1, "EGPRS_DATA_TYPE2" },
{ { 3 * 8 + 7 }, { 3 * 8 + 7 }, 2, 1, "EGPRS_DATA_TYPE3" },
};
enum HeaderType mcs_header_type(enum CodingScheme mcs)
{
return mcs_info[mcs].data_hdr;
}
uint8_t num_data_blocks(enum HeaderType ht)
{
OSMO_ASSERT(ht < NUM_HEADER_TYPES);
return hdr_type_info[ht].num_blocks;
}
uint8_t num_data_header_bits_UL(enum HeaderType ht)
{
OSMO_ASSERT(ht < NUM_HEADER_TYPES);
return hdr_type_info[ht].uplink.data_header_bits;
}
uint8_t num_data_header_bits_DL(enum HeaderType ht)
{
OSMO_ASSERT(ht < NUM_HEADER_TYPES);
return hdr_type_info[ht].downlink.data_header_bits;
}
uint8_t num_data_block_header_bits(enum HeaderType ht)
{
OSMO_ASSERT(ht < NUM_HEADER_TYPES);
return hdr_type_info[ht].data_block_header_bits;
}
const struct value_string mode_names[] = {
{ GPRS, "GPRS" },
{ EGPRS_GMSK, "EGPRS_GMSK-only"},
{ EGPRS, "EGPRS"},
{ 0, NULL }
};
const char *mode_name(enum mcs_kind val) {
return get_value_string(mode_names, val);
}
/* FIXME: take into account padding and special cases of commanded MCS (MCS-6-9 and MCS-5-7) */
enum CodingScheme get_retx_mcs(enum CodingScheme initial_mcs, enum CodingScheme commanded_mcs, bool resegment_bit)
{
OSMO_ASSERT(mcs_is_edge(initial_mcs));
OSMO_ASSERT(mcs_is_edge(commanded_mcs));
OSMO_ASSERT(NUM_SCHEMES - MCS1 == 9);
if (resegment_bit) { /* 3GPP TS 44.060 Table 8.1.1.1, reflected over antidiagonal */
enum CodingScheme egprs_reseg[NUM_SCHEMES - MCS1][NUM_SCHEMES - MCS1] = {
{ MCS1, MCS1, MCS1, MCS1, MCS1, MCS1, MCS1, MCS1, MCS1 },
{ MCS2, MCS2, MCS2, MCS2, MCS2, MCS2, MCS2, MCS2, MCS2 },
{ MCS3, MCS3, MCS3, MCS3, MCS3, MCS3, MCS3, MCS3, MCS3 },
{ MCS1, MCS1, MCS1, MCS4, MCS4, MCS4, MCS4, MCS4, MCS4 },
{ MCS2, MCS2, MCS2, MCS2, MCS5, MCS5, MCS7, MCS7, MCS7 },
{ MCS3, MCS3, MCS3, MCS3, MCS3, MCS6, MCS6, MCS6, MCS9 },
{ MCS2, MCS2, MCS2, MCS2, MCS5, MCS5, MCS7, MCS7, MCS7 },
{ MCS3, MCS3, MCS3, MCS3, MCS3, MCS6, MCS6, MCS8, MCS8 },
{ MCS3, MCS3, MCS3, MCS3, MCS3, MCS6, MCS6, MCS6, MCS9 },
};
return egprs_reseg[mcs_chan_code(initial_mcs)][mcs_chan_code(commanded_mcs)];
} else { /* 3GPP TS 44.060 Table 8.1.1.2, reflected over antidiagonal */
enum CodingScheme egprs_no_reseg[NUM_SCHEMES - MCS1][NUM_SCHEMES - MCS1] = {
{ MCS1, MCS1, MCS1, MCS1, MCS1, MCS1, MCS1, MCS1, MCS1 },
{ MCS2, MCS2, MCS2, MCS2, MCS2, MCS2, MCS2, MCS2, MCS2 },
{ MCS3, MCS3, MCS3, MCS3, MCS3, MCS3, MCS3, MCS3, MCS3 },
{ MCS4, MCS4, MCS4, MCS4, MCS4, MCS4, MCS4, MCS4, MCS4 },
{ MCS5, MCS5, MCS5, MCS5, MCS5, MCS5, MCS7, MCS7, MCS7 },
{ MCS6, MCS6, MCS6, MCS6, MCS6, MCS6, MCS6, MCS6, MCS9 },
{ MCS5, MCS5, MCS5, MCS5, MCS5, MCS5, MCS7, MCS7, MCS7 },
{ MCS6, MCS6, MCS6, MCS6, MCS6, MCS6, MCS6, MCS8, MCS8 },
{ MCS6, MCS6, MCS6, MCS6, MCS6, MCS6, MCS6, MCS6, MCS9 },
};
return egprs_no_reseg[mcs_chan_code(initial_mcs)][mcs_chan_code(commanded_mcs)];
}
}