/*
* Copyright (C) 2013 by Holger Hans Peter Freyther
*
* 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.
*/
#include "bts.h"
#include "gprs_debug.h"
#include <rlc.h>
#include <stdbool.h>
#include <string.h>
#include <sys/types.h>
extern "C" {
#include <osmocom/core/utils.h>
#include <osmocom/core/bitvec.h>
#include <osmocom/core/logging.h>
#include "coding_scheme.h"
}
uint8_t *prepare(struct gprs_rlc_data *rlc, size_t block_data_len)
{
/* todo.. only set it once if it turns out to be a bottleneck */
memset(rlc->block, 0x0, sizeof(rlc->block));
memset(rlc->block, 0x2b, block_data_len);
/* Initial value of puncturing scheme */
rlc->next_ps = EGPRS_PS_1;
return rlc->block;
}
static void gprs_rlc_data_header_init(struct gprs_rlc_data_info *rlc,
enum CodingScheme cs, bool with_padding, unsigned int header_bits,
const unsigned int spb)
{
unsigned int i;
unsigned int padding_bits = with_padding ? mcs_opt_padding_bits(cs) : 0;
rlc->cs = cs;
rlc->r = 0;
rlc->si = 0;
rlc->tfi = 0;
rlc->cps = 0;
rlc->rsb = 0;
rlc->usf = 0;
rlc->es_p = 0;
rlc->rrbp = 0;
rlc->pr = 0;
rlc->num_data_blocks = num_data_blocks(mcs_header_type(cs));
rlc->with_padding = with_padding;
OSMO_ASSERT(rlc->num_data_blocks <= ARRAY_SIZE(rlc->block_info));
for (i = 0; i < rlc->num_data_blocks; i++) {
gprs_rlc_data_block_info_init(&rlc->block_info[i], cs,
with_padding, spb);
rlc->data_offs_bits[i] =
header_bits + padding_bits +
(i+1) * num_data_block_header_bits(mcs_header_type(cs)) +
i * 8 * rlc->block_info[0].data_len;
}
}
void gprs_rlc_data_info_init_dl(struct gprs_rlc_data_info *rlc,
enum CodingScheme cs, bool with_padding, const unsigned int spb)
{
OSMO_ASSERT(mcs_is_valid(cs));
return gprs_rlc_data_header_init(rlc, cs, with_padding,
num_data_header_bits_DL(mcs_header_type(cs)), spb);
}
void gprs_rlc_data_info_init_ul(struct gprs_rlc_data_info *rlc,
enum CodingScheme cs, bool with_padding)
{
OSMO_ASSERT(mcs_is_valid(cs));
/*
* last parameter is sent as 0 since common function used
* for both DL and UL
*/
return gprs_rlc_data_header_init(rlc, cs, with_padding,
num_data_header_bits_UL(mcs_header_type(cs)), 0);
}
void gprs_rlc_data_block_info_init(struct gprs_rlc_data_block_info *rdbi,
enum CodingScheme cs, bool with_padding, const unsigned int spb)
{
unsigned int data_len = mcs_max_data_block_bytes(cs);
if (with_padding)
data_len -= mcs_opt_padding_bits(cs) / 8;
rdbi->data_len = data_len;
rdbi->bsn = 0;
rdbi->ti = 0;
rdbi->e = 1;
rdbi->cv = 15;
rdbi->pi = 0;
rdbi->spb = spb;
}
unsigned int gprs_rlc_mcs_cps(enum CodingScheme cs,
enum egprs_puncturing_values punct,
enum egprs_puncturing_values punct2, bool with_padding)
{
/* validate that punct and punct2 are as expected */
switch (cs) {
case MCS9:
case MCS8:
case MCS7:
if (punct2 == EGPRS_PS_INVALID) {
LOGP(DRLCMACDL, LOGL_ERROR,
"Invalid punct2 value for coding scheme %d: %d\n",
cs, punct2);
return -1;
}
/* fall through */
case MCS6:
case MCS5:
case MCS4:
case MCS3:
case MCS2:
case MCS1:
if (punct == EGPRS_PS_INVALID) {
LOGP(DRLCMACDL, LOGL_ERROR,
"Invalid punct value for coding scheme %d: %d\n",
cs, punct);
return -1;
}
break;
default:
return -1;
}
/* See 3GPP TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1 */
switch (cs) {
case MCS1: return 0b1011 +
punct % EGPRS_MAX_PS_NUM_2;
case MCS2: return 0b1001 +
punct % EGPRS_MAX_PS_NUM_2;
case MCS3: return (with_padding ? 0b0110 : 0b0011) +
punct % EGPRS_MAX_PS_NUM_3;
case MCS4: return 0b0000 +
punct % EGPRS_MAX_PS_NUM_3;
case MCS5: return 0b100 +
punct % EGPRS_MAX_PS_NUM_2;
case MCS6: return (with_padding ? 0b010 : 0b000) +
punct % EGPRS_MAX_PS_NUM_2;
case MCS7: return 0b10100 +
3 * (punct % EGPRS_MAX_PS_NUM_3) +
punct2 % EGPRS_MAX_PS_NUM_3;
case MCS8: return 0b01011 +
3 * (punct % EGPRS_MAX_PS_NUM_3) +
punct2 % EGPRS_MAX_PS_NUM_3;
case MCS9: return 0b00000 +
4 * (punct % EGPRS_MAX_PS_NUM_3) +
punct2 % EGPRS_MAX_PS_NUM_3;
default: ;
}
return -1;
}
void gprs_rlc_mcs_cps_decode(unsigned int cps,
enum CodingScheme cs, int *punct, int *punct2, int *with_padding)
{
*punct2 = -1;
*with_padding = 0;
switch (cs) {
case MCS1:
cps -= 0b1011; *punct = cps % 2; break;
case MCS2:
cps -= 0b1001; *punct = cps % 2; break;
case MCS3:
cps -= 0b0011; *punct = cps % 3; *with_padding = cps >= 3; break;
case MCS4:
cps -= 0b0000; *punct = cps % 3; break;
case MCS5:
cps -= 0b100; *punct = cps % 2; break;
case MCS6:
cps -= 0b000; *punct = cps % 2; *with_padding = cps >= 2; break;
case MCS7:
cps -= 0b10100; *punct = cps / 3; *punct2 = cps % 3; break;
case MCS8:
cps -= 0b01011; *punct = cps / 3; *punct2 = cps % 3; break;
case MCS9:
cps -= 0b00000; *punct = cps / 4; *punct2 = cps % 3; break;
default: ;
}
}
/*
* Finds the PS value for retransmission with MCS change,
* retransmission with no MCS change, fresh transmission cases.
* The return value shall be used for current transmission only
* 44.060 9.3.2.1 defines the PS selection for MCS change case
* cs_current is the output of MCS selection algorithm for retx
* cs is coding scheme of previous transmission of RLC data block
*/
enum egprs_puncturing_values gprs_get_punct_scheme(
enum egprs_puncturing_values punct,
const enum CodingScheme &cs,
const enum CodingScheme &cs_current,
const enum egprs_rlcmac_dl_spb spb)
{
/*
* 10.4.8b of TS 44.060
* If it is second segment of the block
* dont change the puncturing scheme
*/
if (spb == EGPRS_RLCMAC_DL_SEC_SEG)
return punct;
/* TS 44.060 9.3.2.1.1 */
if ((cs == MCS9) &&
(cs_current == MCS6)) {
if ((punct == EGPRS_PS_1) || (punct == EGPRS_PS_3))
return EGPRS_PS_1;
else if (punct == EGPRS_PS_2)
return EGPRS_PS_2;
} else if ((cs == MCS6) &&
(cs_current == MCS9)) {
if (punct == EGPRS_PS_1)
return EGPRS_PS_3;
else if (punct == EGPRS_PS_2)
return EGPRS_PS_2;
} else if ((cs == MCS7) &&
(cs_current == MCS5))
return EGPRS_PS_1;
else if ((cs == MCS5) &&
(cs_current == MCS7))
return EGPRS_PS_2;
else if (cs != cs_current)
return EGPRS_PS_1;
/* TS 44.060 9.3.2.1.1 ends here */
/*
* Below else will handle fresh transmission, retransmission with no
* MCS change case
*/
else
return punct;
return EGPRS_PS_INVALID;
}
/*
* This function calculates puncturing scheme for retransmission of a RLC
* block with same MCS. The computed value shall be used for next transmission
* of the same RLC block
* TS 44.060 10.4.8a.3.1, 10.4.8a.2.1, 10.4.8a.1.1
*/
void gprs_update_punct_scheme(enum egprs_puncturing_values *punct,
const enum CodingScheme &cs)
{
switch (cs) {
case MCS1 :
case MCS2 :
case MCS5 :
case MCS6 :
*punct = ((enum egprs_puncturing_values)((*punct + 1) %
EGPRS_MAX_PS_NUM_2));
break;
case MCS3 :
case MCS4 :
case MCS7 :
case MCS8 :
case MCS9 :
*punct = ((enum egprs_puncturing_values)((*punct + 1) %
EGPRS_MAX_PS_NUM_3));
break;
default:
break;
}
}