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osmo-bts/src/common/measurement.c

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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>
#include <osmo-bts/scheduler.h>
/* Tables as per TS 45.008 Section 8.3 */
static const uint8_t ts45008_83_tch_f[] = { 52, 53, 54, 55, 56, 57, 58, 59 };
static const uint8_t ts45008_83_tch_hs0[] = { 0, 2, 4, 6, 52, 54, 56, 58 };
static const uint8_t ts45008_83_tch_hs1[] = { 14, 16, 18, 29, 66, 68, 70, 72 };
/* find out if an array contains a given key as element */
#define ARRAY_CONTAINS(arr, val) array_contains(arr, ARRAY_SIZE(arr), val)
static bool array_contains(const uint8_t *arr, unsigned int len, uint8_t val) {
int i;
for (i = 0; i < len; i++) {
if (arr[i] == val)
return true;
}
return false;
}
/* Decide if a given frame number is part of the "-SUB" measurements (true) or not (false) */
static bool ts45008_83_is_sub(struct gsm_lchan *lchan, uint32_t fn, bool is_amr_sid_update)
{
uint32_t fn104 = fn % 104;
/* See TS 45.008 Sections 8.3 and 8.4 for a detailed descriptions of the rules
* implemented here. We only implement the logic for Voice, not CSD */
switch (lchan->type) {
case GSM_LCHAN_TCH_F:
switch (lchan->tch_mode) {
case GSM48_CMODE_SIGN:
case GSM48_CMODE_SPEECH_V1:
case GSM48_CMODE_SPEECH_EFR:
if (trx_sched_is_sacch_fn(lchan->ts, fn, true))
return true;
if (ARRAY_CONTAINS(ts45008_83_tch_f, fn104))
return true;
break;
case GSM48_CMODE_SPEECH_AMR:
if (trx_sched_is_sacch_fn(lchan->ts, fn, true))
return true;
if (is_amr_sid_update)
return true;
break;
default:
LOGPFN(DMEAS, LOGL_ERROR, fn, "%s: Unsupported lchan->tch_mode %u\n",
gsm_lchan_name(lchan), lchan->tch_mode);
break;
}
break;
case GSM_LCHAN_TCH_H:
switch (lchan->tch_mode) {
case GSM48_CMODE_SPEECH_V1:
if (trx_sched_is_sacch_fn(lchan->ts, fn, true))
return true;
switch (lchan->nr) {
case 0:
if (ARRAY_CONTAINS(ts45008_83_tch_hs0, fn104))
return true;
break;
case 1:
if (ARRAY_CONTAINS(ts45008_83_tch_hs1, fn104))
return true;
break;
default:
OSMO_ASSERT(0);
}
break;
case GSM48_CMODE_SPEECH_AMR:
if (trx_sched_is_sacch_fn(lchan->ts, fn, true))
return true;
if (is_amr_sid_update)
return true;
break;
case GSM48_CMODE_SIGN:
/* No DTX allowed; SUB=FULL, therefore measurements at all frame numbers are
* SUB */
return true;
default:
LOGPFN(DMEAS, LOGL_ERROR, fn, "%s: Unsupported lchan->tch_mode %u\n",
gsm_lchan_name(lchan), lchan->tch_mode);
break;
}
break;
case GSM_LCHAN_SDCCH:
/* No DTX allowed; SUB=FULL, therefore measurements at all frame numbers are SUB */
return true;
default:
break;
}
return false;
}
/* Measurement reporting period and mapping of SACCH message block for TCHF
* and TCHH chan As per in 3GPP TS 45.008, section 8.4.1.
*
* Timeslot number (TN) TDMA frame number (FN) modulo 104
* Half rate, Half rate, Reporting SACCH
* Full Rate subch.0 subch.1 period Message block
* 0 0 and 1 0 to 103 12, 38, 64, 90
* 1 0 and 1 13 to 12 25, 51, 77, 103
* 2 2 and 3 26 to 25 38, 64, 90, 12
* 3 2 and 3 39 to 38 51, 77, 103, 25
* 4 4 and 5 52 to 51 64, 90, 12, 38
* 5 4 and 5 65 to 64 77, 103, 25, 51
* 6 6 and 7 78 to 77 90, 12, 38, 64
* 7 6 and 7 91 to 90 103, 25, 51, 77 */
static const uint8_t tchf_meas_rep_fn104[] = {
[0] = 90,
[1] = 103,
[2] = 12,
[3] = 25,
[4] = 38,
[5] = 51,
[6] = 64,
[7] = 77,
};
static const uint8_t tchh0_meas_rep_fn104[] = {
[0] = 90,
[1] = 90,
[2] = 12,
[3] = 12,
[4] = 38,
[5] = 38,
[6] = 64,
[7] = 64,
};
static const uint8_t tchh1_meas_rep_fn104[] = {
[0] = 103,
[1] = 103,
[2] = 25,
[3] = 25,
[4] = 51,
[5] = 51,
[6] = 77,
[7] = 77,
};
/* Measurement reporting period for SDCCH8 and SDCCH4 chan
* As per in 3GPP TS 45.008, section 8.4.2.
*
* Logical Chan TDMA frame number
* (FN) modulo 102
*
* SDCCH/8 12 to 11
* SDCCH/4 37 to 36
*/
/* FN of the first burst whose block completes before reaching fn%102=11 */
static const uint8_t sdcch8_meas_rep_fn102[] = {
[0] = 66, /* 15(SDCCH), 47(SACCH), 66(SDCCH) */
[1] = 70, /* 19(SDCCH), 51(SACCH), 70(SDCCH) */
[2] = 74, /* 23(SDCCH), 55(SACCH), 74(SDCCH) */
[3] = 78, /* 27(SDCCH), 59(SACCH), 78(SDCCH) */
[4] = 98, /* 31(SDCCH), 98(SACCH), 82(SDCCH) */
[5] = 0, /* 35(SDCCH), 0(SACCH), 86(SDCCH) */
[6] = 4, /* 39(SDCCH), 4(SACCH), 90(SDCCH) */
[7] = 8, /* 43(SDCCH), 8(SACCH), 94(SDCCH) */
};
/* FN of the first burst whose block completes before reaching fn%102=37 */
static const uint8_t sdcch4_meas_rep_fn102[] = {
[0] = 88, /* 37(SDCCH), 57(SACCH), 88(SDCCH) */
[1] = 92, /* 41(SDCCH), 61(SACCH), 92(SDCCH) */
[2] = 6, /* 6(SACCH), 47(SDCCH), 98(SDCCH) */
[3] = 10 /* 10(SACCH), 0(SDCCH), 51(SDCCH) */
};
/* Note: The reporting of the measurement results is done via the SACCH channel.
* The measurement interval is not aligned with the interval in which the
* SACCH is transmitted. When we receive the measurement indication with the
* SACCH block, the corresponding measurement interval will already have ended
* and we will get the results late, but on spot with the beginning of the
* next measurement interval.
*
* For example: We get a measurement indication on FN%104=38 in TS=2. Then we
* will have to look at 3GPP TS 45.008, section 8.4.1 (or 3GPP TS 05.02 Clause 7
* Table 1 of 9) what value we need to feed into the lookup tables in order to
* detect the measurement period ending. In this example the "real" ending
* was on FN%104=12. This is the value we have to look for in
* tchf_meas_rep_fn104 to know that a measurement period has just ended. */
/* See also 3GPP TS 05.02 Clause 7 Table 1 of 9:
* Mapping of logical channels onto physical channels (see subclauses 6.3, 6.4, 6.5) */
static uint8_t translate_tch_meas_rep_fn104(uint8_t fn_mod)
{
switch (fn_mod) {
case 25:
return 103;
case 38:
return 12;
case 51:
return 25;
case 64:
return 38;
case 77:
return 51;
case 90:
return 64;
case 103:
return 77;
case 12:
return 90;
}
/* Invalid / not of interest */
return 0;
}
/* determine if a measurement period ends at the given frame number */
static int is_meas_complete(struct gsm_lchan *lchan, uint32_t fn)
{
unsigned int fn_mod = -1;
const uint8_t *tbl;
int rc = 0;
enum gsm_phys_chan_config pchan = ts_pchan(lchan->ts);
if (lchan->ts->nr >= 8)
return -EINVAL;
if (pchan >= _GSM_PCHAN_MAX)
return -EINVAL;
switch (pchan) {
case GSM_PCHAN_TCH_F:
fn_mod = translate_tch_meas_rep_fn104(fn % 104);
if (tchf_meas_rep_fn104[lchan->ts->nr] == fn_mod)
rc = 1;
break;
case GSM_PCHAN_TCH_H:
fn_mod = translate_tch_meas_rep_fn104(fn % 104);
if (lchan->nr == 0)
tbl = tchh0_meas_rep_fn104;
else
tbl = tchh1_meas_rep_fn104;
if (tbl[lchan->ts->nr] == fn_mod)
rc = 1;
break;
case GSM_PCHAN_SDCCH8_SACCH8C:
case GSM_PCHAN_SDCCH8_SACCH8C_CBCH:
fn_mod = fn % 102;
if (sdcch8_meas_rep_fn102[lchan->nr] == fn_mod)
rc = 1;
break;
case GSM_PCHAN_CCCH_SDCCH4:
case GSM_PCHAN_CCCH_SDCCH4_CBCH:
fn_mod = fn % 102;
if (sdcch4_meas_rep_fn102[lchan->nr] == fn_mod)
rc = 1;
break;
default:
rc = 0;
break;
}
if (rc == 1) {
DEBUGP(DMEAS,
"%s meas period end fn:%u, fn_mod:%i, status:%d, pchan:%s\n",
gsm_lchan_name(lchan), fn, fn_mod, rc, gsm_pchan_name(pchan));
}
return rc;
}
/* receive a L1 uplink measurement from L1 */
int lchan_new_ul_meas(struct gsm_lchan *lchan, struct bts_ul_meas *ulm, uint32_t fn)
{
if (lchan->state != LCHAN_S_ACTIVE) {
LOGPFN(DMEAS, LOGL_NOTICE, fn,
"%s measurement during state: %s, num_ul_meas=%d\n",
gsm_lchan_name(lchan), gsm_lchans_name(lchan->state),
lchan->meas.num_ul_meas);
}
if (lchan->meas.num_ul_meas >= ARRAY_SIZE(lchan->meas.uplink)) {
LOGPFN(DMEAS, LOGL_NOTICE, fn,
"%s no space for uplink measurement, num_ul_meas=%d\n",
gsm_lchan_name(lchan), lchan->meas.num_ul_meas);
return -ENOSPC;
}
/* We expect the lower layers to mark AMR SID_UPDATE frames already as such.
* In this function, we only deal with the comon logic as per the TS 45.008 tables */
if (!ulm->is_sub)
ulm->is_sub = ts45008_83_is_sub(lchan, fn, false);
DEBUGPFN(DMEAS, fn, "%s adding measurement (is_sub=%u), num_ul_meas=%d\n",
gsm_lchan_name(lchan), ulm->is_sub, lchan->meas.num_ul_meas);
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)
{
/* Eight levels of Rx quality are defined and are mapped to the
* equivalent BER before channel decoding, as per in 3GPP TS 45.008,
* secton 8.2.4.
*
* RxQual: BER Range:
* RXQUAL_0 BER < 0,2 % Assumed value = 0,14 %
* RXQUAL_1 0,2 % < BER < 0,4 % Assumed value = 0,28 %
* RXQUAL_2 0,4 % < BER < 0,8 % Assumed value = 0,57 %
* RXQUAL_3 0,8 % < BER < 1,6 % Assumed value = 1,13 %
* RXQUAL_4 1,6 % < BER < 3,2 % Assumed value = 2,26 %
* RXQUAL_5 3,2 % < BER < 6,4 % Assumed value = 4,53 %
* RXQUAL_6 6,4 % < BER < 12,8 % Assumed value = 9,05 %
* RXQUAL_7 12,8 % < BER Assumed value = 18,10 % */
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)
{
struct gsm_meas_rep_unidir *mru;
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 ta256b_sum = 0;
unsigned int num_meas_sub = 0;
int i;
/* if measurement period is not complete, abort */
if (!is_meas_complete(lchan, 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;
ta256b_sum += m->ta_offs_256bits;
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;
ta256b_sum = ta256b_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;
} else {
LOGP(DMEAS, LOGL_ERROR, "%s No measurements for SUB!!!\n", gsm_lchan_name(lchan));
/* The only situation in which this can occur is if the related uplink burst/block was
* missing, so let's set BER to 100% and level to lowest possible. */
ber_sub_sum = 10000; /* 100% */
irssi_sub_sum = 120; /* -120 dBm */
}
LOGP(DMEAS, LOGL_INFO, "%s Computed TA256(% 4d) BER-FULL(%2u.%02u%%), RSSI-FULL(-%3udBm), "
"BER-SUB(%2u.%02u%%), RSSI-SUB(-%3udBm)\n", gsm_lchan_name(lchan),
ta256b_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 */
mru = &lchan->meas.ul_res;
mru->full.rx_lev = dbm2rxlev((int)irssi_full_sum * -1);
mru->sub.rx_lev = dbm2rxlev((int)irssi_sub_sum * -1);
mru->full.rx_qual = ber10k_to_rxqual(ber_full_sum);
mru->sub.rx_qual = ber10k_to_rxqual(ber_sub_sum);
lchan->meas.ms_toa256 = ta256b_sum;
LOGP(DMEAS, LOGL_INFO, "%s UL MEAS RXLEV_FULL(%u), RXLEV_SUB(%u),"
"RXQUAL_FULL(%u), RXQUAL_SUB(%u), num_meas_sub(%u), num_ul_meas(%u) \n",
gsm_lchan_name(lchan),
mru->full.rx_lev,
mru->sub.rx_lev,
mru->full.rx_qual,
mru->sub.rx_qual, num_meas_sub, lchan->meas.num_ul_meas);
lchan->meas.flags |= LC_UL_M_F_RES_VALID;
lchan->meas.num_ul_meas = 0;
/* send a signal indicating computation is complete */
return 1;
}
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