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#include <stdint.h>
#include <errno.h>
#include <osmocom/gsm/gsm_utils.h>
#include <osmo-bts/gsm_data.h>
#include <osmo-bts/logging.h>
#include <osmo-bts/measurement.h>
/* TS 05.08, Chapter 8.4.1 */
/* measurement period ends at fn % 104 == ? */
static const uint8_t tchf_meas_rep_fn104[] = {
[0] = 103,
[1] = 12,
[2] = 25,
[3] = 38,
[4] = 51,
[5] = 64,
[6] = 77,
[7] = 90,
};
static const uint8_t tchh0_meas_rep_fn104[] = {
[0] = 103,
[1] = 103,
[2] = 25,
[3] = 25,
[4] = 51,
[5] = 51,
[6] = 77,
[7] = 77,
};
static const uint8_t tchh1_meas_rep_fn104[] = {
[0] = 12,
[1] = 12,
[2] = 38,
[3] = 38,
[4] = 64,
[5] = 64,
[6] = 90,
[7] = 90,
};
/* determine if a measurement period ends at the given frame number */
static int is_meas_complete(enum gsm_phys_chan_config pchan, unsigned int ts,
unsigned int subch, uint32_t fn)
{
unsigned int fn_mod;
const uint8_t *tbl;
int rc = 0;
if (ts >= 8)
return -EINVAL;
if (pchan >= _GSM_PCHAN_MAX)
return -EINVAL;
switch (pchan) {
case GSM_PCHAN_TCH_F:
fn_mod = fn % 104;
if (tchf_meas_rep_fn104[ts] == fn_mod)
rc = 1;
break;
case GSM_PCHAN_TCH_H:
fn_mod = fn % 104;
if (subch == 0)
tbl = tchh0_meas_rep_fn104;
else
tbl = tchh1_meas_rep_fn104;
if (tbl[ts] == fn_mod)
rc = 1;
break;
case GSM_PCHAN_SDCCH8_SACCH8C:
fn_mod = fn % 102;
if (fn_mod == 11)
rc = 1;
break;
case GSM_PCHAN_CCCH_SDCCH4:
fn_mod = fn % 102;
if (fn_mod == 36)
rc = 1;
break;
default:
rc = 0;
break;
}
return rc;
}
/* receive a L1 uplink measurement from L1 */
int lchan_new_ul_meas(struct gsm_lchan *lchan, struct bts_ul_meas *ulm)
{
DEBUGP(DMEAS, "%s adding measurement, num_ul_meas=%d\n",
gsm_lchan_name(lchan), lchan->meas.num_ul_meas);
if (lchan->meas.num_ul_meas >= ARRAY_SIZE(lchan->meas.uplink)) {
LOGP(DMEAS, LOGL_NOTICE, "%s no space for uplink measurement\n",
gsm_lchan_name(lchan));
return -ENOSPC;
}
memcpy(&lchan->meas.uplink[lchan->meas.num_ul_meas++], ulm,
sizeof(*ulm));
return 0;
}
/* input: BER in steps of .01%, i.e. percent/100 */
static uint8_t ber10k_to_rxqual(uint32_t ber10k)
{
/* 05.08 / 8.2.4 */
if (ber10k < 20)
return 0;
if (ber10k < 40)
return 1;
if (ber10k < 80)
return 2;
if (ber10k < 160)
return 3;
if (ber10k < 320)
return 4;
if (ber10k < 640)
return 5;
if (ber10k < 1280)
return 6;
return 7;
}
int lchan_meas_check_compute(struct gsm_lchan *lchan, uint32_t fn)
{
uint32_t ber_full_sum = 0;
uint32_t irssi_full_sum = 0;
uint32_t ber_sub_sum = 0;
uint32_t irssi_sub_sum = 0;
int32_t taqb_sum = 0;
unsigned int num_meas_sub = 0;
int i;
/* if measurement period is not complete, abort */
if (!is_meas_complete(lchan->ts->pchan, lchan->ts->nr,
lchan->nr, fn))
return 0;
/* if there are no measurements, skip computation */
if (lchan->meas.num_ul_meas == 0)
return 0;
/* compute the actual measurements */
/* step 1: add up */
for (i = 0; i < lchan->meas.num_ul_meas; i++) {
struct bts_ul_meas *m = &lchan->meas.uplink[i];
ber_full_sum += m->ber10k;
irssi_full_sum += m->inv_rssi;
taqb_sum += m->ta_offs_qbits;
if (m->is_sub) {
num_meas_sub++;
ber_sub_sum += m->ber10k;
irssi_sub_sum += m->inv_rssi;
}
}
/* step 2: divide */
ber_full_sum = ber_full_sum / lchan->meas.num_ul_meas;
irssi_full_sum = irssi_full_sum / lchan->meas.num_ul_meas;
taqb_sum = taqb_sum / lchan->meas.num_ul_meas;
if (num_meas_sub) {
ber_sub_sum = ber_sub_sum / num_meas_sub;
irssi_sub_sum = irssi_sub_sum / num_meas_sub;
}
DEBUGP(DMEAS, "%s Computed TA(% 4dqb) BER-FULL(%2u.%02u%%), RSSI-FULL(-%3udBm), "
"BER-SUB(%2u.%02u%%), RSSI-SUB(-%3udBm)", gsm_lchan_name(lchan),
taqb_sum, ber_full_sum/100,
ber_full_sum%100, irssi_full_sum, ber_sub_sum/100, ber_sub_sum%100,
irssi_sub_sum);
/* store results */
lchan->meas.res.rxlev_full = dbm2rxlev((int)irssi_full_sum * -1);
lchan->meas.res.rxlev_sub = dbm2rxlev((int)irssi_sub_sum * -1);
lchan->meas.res.rxqual_full = ber10k_to_rxqual(ber_full_sum);
lchan->meas.res.rxqual_sub = ber10k_to_rxqual(ber_sub_sum);
lchan->meas.flags |= LC_UL_M_F_RES_VALID;
lchan->meas.num_ul_meas = 0;
/* send a signal indicating computation is complete */
return 1;
}
/* build the 3 byte RSL uplinke measurement IE content */
int lchan_build_rsl_ul_meas(struct gsm_lchan *lchan, uint8_t *buf)
{
buf[0] = (lchan->meas.res.rxlev_full & 0x3f); /* FIXME: DTXu support */
buf[1] = (lchan->meas.res.rxlev_sub & 0x3f);
buf[2] = ((lchan->meas.res.rxqual_full & 7) << 3) |
(lchan->meas.res.rxqual_sub & 7);
return 3;
}
int ts_meas_check_compute(struct gsm_bts_trx_ts *ts, uint32_t fn)
{
int i;
for (i = 0; i < ARRAY_SIZE(ts->lchan); i++) {
struct gsm_lchan *lchan = &ts->lchan[i];
if (lchan->state != LCHAN_S_ACTIVE)
continue;
switch (lchan->type) {
case GSM_LCHAN_SDCCH:
case GSM_LCHAN_TCH_F:
case GSM_LCHAN_TCH_H:
lchan_meas_check_compute(lchan, fn);
break;
default:
break;
}
}
return 0;
}
/* needs to be called once every TDMA frame ! */
int trx_meas_check_compute(struct gsm_bts_trx *trx, uint32_t fn)
{
int i;
for (i = 0; i < ARRAY_SIZE(trx->ts); i++) {
struct gsm_bts_trx_ts *ts = &trx->ts[i];
ts_meas_check_compute(ts, fn);
}
return 0;
}
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