fixeria has submitted this change. (
https://gerrit.osmocom.org/c/osmo-bts/+/27550 )
Change subject: osmo-bts-trx: rx_tchh_fn(): use proper meas averaging mode
......................................................................
osmo-bts-trx: rx_tchh_fn(): use proper meas averaging mode
Compared to TCH/F, TCH/H is a bit special in a way that:
* speech frames are interleaved over 4 consecutive bursts,
* while FACCH frames are interleaved over 6 consecutive bursts.
This is why in rx_tchh_fn() we allocate a buffer large enough to
store up to 6 bursts. Let's say we have that buffer filled up
completely with all 6 bursts (from 'a' to 'f'). Now attempting
to decode them may yield either a speech frame or a FACCH frame:
+---+---+---+---+---+---+
| a | b | c | d | e | f | Burst 'a' received first, 'f' last
+---+---+---+---+---+---+
^^^^^^^^^^^^^^^ Speech frame (bursts 'a' .. 'd')
^^^^^^^^^^^^^^^^^^^^^^^ FACCH frame (bursts 'a' .. 'f')
For FACCH we use measurement averaging mode SCHED_MEAS_AVG_M_S6N6,
so that 6 last samples are averaged - so far so good. For speech
we use SCHED_MEAS_AVG_M_S4N4, so that 4 last samples corresponding
to bursts 'c', 'd', 'e', 'f' are averaged - this is wrong.
We actually need to average the *first* 4 samples corresponding to
bursts 'a', 'b', 'c', 'd' in the case of speech. Let's add and use
a new averaging mode SCHED_MEAS_AVG_M_S6N4 for that.
Change-Id: Iea6f4e5471550f4c2b57aaebeac83c80e879489d
---
M include/osmo-bts/scheduler.h
M src/osmo-bts-trx/sched_lchan_tchh.c
M src/osmo-bts-trx/scheduler_trx.c
3 files changed, 5 insertions(+), 2 deletions(-)
Approvals:
Jenkins Builder: Verified
osmith: Looks good to me, but someone else must approve
laforge: Looks good to me, approved
diff --git a/include/osmo-bts/scheduler.h b/include/osmo-bts/scheduler.h
index 8643edd..1e1a2d7 100644
--- a/include/osmo-bts/scheduler.h
+++ b/include/osmo-bts/scheduler.h
@@ -306,10 +306,12 @@
/* Averaging mode for trx_sched_meas_avg() */
enum sched_meas_avg_mode {
- /* last 4 bursts (default for xCCH, TCH/H, PTCCH and PDTCH) */
+ /* last 4 bursts (default for xCCH, PTCCH and PDTCH) */
SCHED_MEAS_AVG_M_S4N4,
/* last 8 bursts (default for TCH/F and FACCH/F) */
SCHED_MEAS_AVG_M_S8N8,
+ /* first 4 of last 6 bursts (default for TCH/H) */
+ SCHED_MEAS_AVG_M_S6N4,
/* last 6 bursts (default for FACCH/H) */
SCHED_MEAS_AVG_M_S6N6,
/* first 4 of last 8 bursts */
diff --git a/src/osmo-bts-trx/sched_lchan_tchh.c
b/src/osmo-bts-trx/sched_lchan_tchh.c
index 8264163..edbb566 100644
--- a/src/osmo-bts-trx/sched_lchan_tchh.c
+++ b/src/osmo-bts-trx/sched_lchan_tchh.c
@@ -64,7 +64,7 @@
* Even FN ending at: 10,11,19,20,2,3
*/
int fn_is_odd = (((bi->fn + 26 - 10) % 26) >> 2) & 1;
- enum sched_meas_avg_mode meas_avg_mode = SCHED_MEAS_AVG_M_S4N4;
+ enum sched_meas_avg_mode meas_avg_mode = SCHED_MEAS_AVG_M_S6N4;
struct l1sched_meas_set meas_avg;
unsigned int fn_begin;
unsigned int fn_tch_end;
diff --git a/src/osmo-bts-trx/scheduler_trx.c b/src/osmo-bts-trx/scheduler_trx.c
index 78c7b4a..6ce5a9a 100644
--- a/src/osmo-bts-trx/scheduler_trx.c
+++ b/src/osmo-bts-trx/scheduler_trx.c
@@ -635,6 +635,7 @@
static const uint8_t trx_sched_meas_modeset[][2] = {
[SCHED_MEAS_AVG_M_S4N4] = { 4, 4 },
[SCHED_MEAS_AVG_M_S8N8] = { 8, 8 },
+ [SCHED_MEAS_AVG_M_S6N4] = { 6, 4 },
[SCHED_MEAS_AVG_M_S6N6] = { 6, 6 },
[SCHED_MEAS_AVG_M_S8N4] = { 8, 4 },
[SCHED_MEAS_AVG_M_S6N2] = { 6, 2 },
--
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Gerrit-Project: osmo-bts
Gerrit-Branch: master
Gerrit-Change-Id: Iea6f4e5471550f4c2b57aaebeac83c80e879489d
Gerrit-Change-Number: 27550
Gerrit-PatchSet: 1
Gerrit-Owner: fixeria <[email protected]>
Gerrit-Reviewer: Jenkins Builder
Gerrit-Reviewer: fixeria <[email protected]>
Gerrit-Reviewer: laforge <[email protected]>
Gerrit-Reviewer: osmith <[email protected]>
Gerrit-MessageType: merged
