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osmo-bts-trx: rx_tchh_fn(): get rid of chan_state->meas_avg_facch 

FACCH/H takes out two speech frames, so we send two BFIs once we
have received it in rx_tchh_fn().  The upper layers responsible
for handling of the Uplink measurements expect a fixed amount of
measurement samples, so currently we do:

* send a FACCH frame with the associated measurememnts (S6N6),
* send the 1st BFI with invalidated measurements (RSSI=0),
* send the 2nd BFI with the stored measurememnts of FACCH.

This is achieved by preserving a copy of the FACCH measurememnts
in chan_state->meas_avg_facch and then using it two bursts later.

The same goal can be achieved a lot easier by sending the associated
measurements with both BFIs as if no FACCH was received:

* send a FACCH frame with invalidated measurememnts (RSSI=0),
* send the 1st BFI with the associated measurememnts (S6N4),
* send the 2nd BFI with the associated measurememnts (S6N4).

This eliminates the need to store anything outside of the existing
measurement history and simplifies the code a lot.  Also, this
eliminates the need for using a dedicated averaging mode S6N6.

Varified by running BTS_Tests.TC_meas_res_speech_tchh_facch.

Change-Id: I7902b4709bc3f418174e8373f52e87bb31cdc826
Related: I1ad9fa3815feb2b4da608ab7df716a87ba1f2f91
This commit is contained in:
Vadim Yanitskiy 2022-03-18 15:30:49 +03:00 committed by fixeria
parent bd7ef4101b
commit da433bba7b
2 changed files with 7 additions and 32 deletions
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1
include/osmo-bts/scheduler.h
View File

@ -125,7 +125,6 @@ struct l1sched_chan_state {
/* TCH/H */
uint8_t dl_ongoing_facch; /* FACCH/H on downlink */
uint8_t ul_ongoing_facch; /* FACCH/H on uplink */
struct l1sched_meas_set meas_avg_facch; /* measurement results for last FACCH */
uint8_t dl_facch_bursts; /* number of remaining DL FACCH bursts */

38
src/osmo-bts-trx/sched_lchan_tchh.c
View File

@ -71,7 +71,6 @@ int rx_tchh_fn(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi)
uint16_t ber10k = 0;
uint8_t is_sub = 0;
uint8_t ft;
bool mask_stolen_tch_block = false;
bool fn_is_cmi;
/* If handover RACH detection is turned on, treat this burst as an Access Burst.
@ -127,11 +126,7 @@ int rx_tchh_fn(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi)
memcpy(*bursts_p + 232, *bursts_p + 464, 232);
/* we have already sent the first BFI when a FACCH/H frame
* was decoded (see below), now send the second one. */
memset(&meas_avg, 0, sizeof(meas_avg));
/* In order to provide an even stream of measurement reports
* we ask the code below to mask the missing TCH/H block
* measurement report with the FACCH measurement results. */
mask_stolen_tch_block = true;
trx_sched_meas_avg(chan_state, &meas_avg, meas_avg_mode);
goto bfi;
}
@ -248,8 +243,6 @@ int rx_tchh_fn(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi)
ber10k = compute_ber10k(n_bits_total, n_errors);
/* average measurements of the last N (depends on mode) bursts */
if (rc == GSM_MACBLOCK_LEN)
meas_avg_mode = SCHED_MEAS_AVG_M_S6N6;
trx_sched_meas_avg(chan_state, &meas_avg, meas_avg_mode);
/* Check if the frame is bad */
@ -277,22 +270,15 @@ int rx_tchh_fn(struct l1sched_ts *l1ts, const struct trx_ul_burst_ind *bi)
fn_begin = gsm0502_fn_remap(bi->fn, FN_REMAP_FACCH_H0);
else
fn_begin = gsm0502_fn_remap(bi->fn, FN_REMAP_FACCH_H1);
/* In order to provide an even stream of measurement reports, here we
* intentionally invalidate RSSI, so that this report gets dropped in
* process_l1sap_meas_data(). The averaged results will still be sent
* with the first BFI (see below). */
_sched_compose_ph_data_ind(l1ts, fn_begin, bi->chan,
tch_data + amr, GSM_MACBLOCK_LEN,
meas_avg.rssi, meas_avg.toa256,
meas_avg.ci_cb, ber10k,
0, /* intentionally invalidate RSSI */
meas_avg.toa256, meas_avg.ci_cb, ber10k,
PRES_INFO_UNKNOWN);
/* Keep a copy of the measurement results of the last FACCH
* transmission in order to be able to create a replacement
* measurement result for the one missing TCH block
* measurement */
memcpy(&chan_state->meas_avg_facch, &meas_avg, sizeof(meas_avg));
/* Invalidate the current measurement result to prevent the
* code below from handing up the current measurement a second
* time. */
memset(&meas_avg, 0, sizeof(meas_avg));
ber10k = 0;
bfi:
/* A FACCH/H frame replaces two speech frames, so we need to send two BFIs.
@ -363,16 +349,6 @@ compose_l1sap:
else
fn_begin = gsm0502_fn_remap(fn_tch_end, FN_REMAP_TCH_H1);
/* A FACCH/H transmission takes out two TCH/H voice blocks and the
* related measurement results. The first measurement result is handed
* up directly with the FACCH (see above), the second one needs to be
* compensated by filling the gap with the measurement result we got
* from the FACCH transmission. */
if (mask_stolen_tch_block) {
memcpy(&meas_avg, &chan_state->meas_avg_facch, sizeof(meas_avg));
memset(&chan_state->meas_avg_facch, 0, sizeof(meas_avg));
}
return _sched_compose_tch_ind(l1ts, fn_begin, bi->chan, tch_data, rc,
/* FIXME: what should we use for BFI here? */
bfi_flag ? bi->toa256 : meas_avg.toa256, ber10k,