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Bug #1524

PACCH on the wrong timeslot

Added by zecke almost 2 years ago. Updated 7 months ago.

Status:
Stalled
Priority:
High
Assignee:
Target version:
-
Start date:
02/22/2016
Due date:
% Done:

0%

Spec Reference:

Description

The PACCH is probably on the wrong timeslot and both the E71 and the iPhone5c do not care about it but the Acer Z200 with a Mediatek chipset runs into frequent timeouts on GPRS/EGPRS downloads. This phone is frequently used by a user of osmo-pcu.

Jacob has prepared but not finished some work to have the PACCH on the "right" (it can change due new uplink assignments) timeslot. The Mediatek based system is likely to easily reproduce the issue.

The symptom is frequently seeing POLL timeouts. This means that the PCU expected an answer from the phone but it never occurred. The first step should be to reproduce the issue.

osmopcu-1.log Magnifier (8.22 KB) msuraev, 02/24/2016 03:44 PM

osmopcu-2.log Magnifier (101 KB) msuraev, 02/24/2016 05:00 PM

pcu.pcapng.gz (1.27 MB) msuraev, 02/25/2016 10:32 AM

debug.log Magnifier (2.35 MB) msuraev, 02/25/2016 10:32 AM


Related issues

Related to OsmoBTS - Bug #1795: osmo-bts-trx: fails to assign second lchan on TCH/H TS Closed 08/09/2016
Related to OsmoBTS - Feature #1648: Verify Multi-TRX support for osmo-bts-trx Closed 03/11/2016
Related to OsmoPCU - Feature #1526: Acquire/update timing advance (TA) In Progress 02/22/2016
Related to OsmoPCU - Feature #2709: use osmo_fsm for TBF New 12/05/2017
Related to OsmoPCU - Bug #1532: Increased number of poll timeouts on shared PDCHs New 02/22/2016

History

#1 Updated by zecke almost 2 years ago

  • Assignee set to msuraev

#2 Updated by msuraev almost 2 years ago

Testing results of jerlbeck/wip/pacch-handling branch:

  • iphone: couple of errors seen after surfing for few minutes, surfing itself is not affected
  • acer: a lot of errors seen, surfing fails until phone is pinged from host, after that surfing is possible although there are still plenty of errors

Errors looks as follows:
Mon Feb 22 15:41:29 2016 <0002> tbf.cpp:485 TBF poll timeout for FN=1539512, TS=4 (curr FN 1539525)
Mon Feb 22 15:41:29 2016 <0002> tbf.cpp:557 - Timeout for polling PACKET DOWNLINK ACK.
Mon Feb 22 15:41:29 2016 <0002> tbf.cpp:902 - Assignment was on PACCH
Mon Feb 22 15:41:29 2016 <0002> tbf.cpp:908 - Downlink ACK was received
Mon Feb 22 15:41:31 2016 <0002> tbf.cpp:485 TBF poll timeout for FN=1540010, TS=4 (curr FN 1540023)
Mon Feb 22 15:41:31 2016 <0002> tbf.cpp:557 - Timeout for polling PACKET DOWNLINK ACK.
Mon Feb 22 15:41:31 2016 <0002> tbf.cpp:902 - Assignment was on PACCH
Mon Feb 22 15:41:31 2016 <0002> tbf.cpp:908 - Downlink ACK was received
Mon Feb 22 15:41:34 2016 <0002> tbf.cpp:485 TBF poll timeout for FN=1540534, TS=4 (curr FN 1540547)
Mon Feb 22 15:41:34 2016 <0002> tbf.cpp:557 - Timeout for polling PACKET DOWNLINK ACK.
Mon Feb 22 15:41:34 2016 <0002> tbf.cpp:902 - Assignment was on PACCH
Mon Feb 22 15:41:34 2016 <0002> tbf.cpp:908 - Downlink ACK was received

The most common is "DOWNLINK ACK" but sometimes others appear as well: "CONTROL ACK for PACKET UPLINK ASSIGNMENT" for example.

#3 Updated by zecke almost 2 years ago

  • Status changed from New to In Progress

#4 Updated by msuraev almost 2 years ago

Testing master branch gave the same results.

While testing with telenor modem I was unable to reproduce issue with either branch.

#5 Updated by zecke almost 2 years ago

On 23 Feb 2016, at 15:42, ms [REDMINE] <> wrote:

Testing master branch gave the same results.

While testing with gxdm/telenor modem I was unable to reproduce issue with either branch.

We know that qualcomm firmware is quite forgiven. Let's stick with the Mediatek/Acerphone for the tests. Mattias mentioned a Sony Ericsson W995 as picky as well.

#6 Updated by msuraev almost 2 years ago

Attached is the log with extra debug info obtained from osmopcu with acer phone trying to connect.

#7 Updated by msuraev almost 2 years ago

Bigger and cleaner log for reference.

#8 Updated by msuraev almost 2 years ago

Attaching latest logs.

#9 Updated by msuraev almost 2 years ago

Curiously, when changing timeslot configuration in osmo-nitb.cfg from:
timeslot 0
phys_chan_config CCCH+SDCCH4
hopping enabled 0
timeslot 1
phys_chan_config SDCCH8
hopping enabled 0
timeslot 2
phys_chan_config PDCH
hopping enabled 0
timeslot 3
phys_chan_config PDCH
hopping enabled 0
timeslot 4
phys_chan_config PDCH
hopping enabled 0
timeslot 5
phys_chan_config PDCH
hopping enabled 0
timeslot 6
phys_chan_config PDCH
hopping enabled 0
timeslot 7
phys_chan_config TCH/H
hopping enabled 0
to:
timeslot 0
phys_chan_config CCCH+SDCCH4
hopping enabled 0
timeslot 1
phys_chan_config SDCCH8
hopping enabled 0
timeslot 2
phys_chan_config PDCH
hopping enabled 0
timeslot 3
phys_chan_config TCH/F
hopping enabled 0
timeslot 4
phys_chan_config PDCH
hopping enabled 0
timeslot 5
phys_chan_config TCH/F
hopping enabled 0
timeslot 6
phys_chan_config PDCH
hopping enabled 0
timeslot 7
phys_chan_config TCH/H
hopping enabled 0

Have not done any extensive testing over different timeslot configurations so could be just a single outlier.

#10 Updated by msuraev almost 2 years ago

The config change above makes acer phone work albeit slow.

#11 Updated by laforge over 1 year ago

  • Status changed from In Progress to New

#12 Updated by msuraev about 1 year ago

  • Related to Bug #1795: osmo-bts-trx: fails to assign second lchan on TCH/H TS added

#13 Updated by laforge about 1 year ago

  • Priority changed from Normal to High

#14 Updated by msuraev about 1 year ago

  • Status changed from New to Stalled

#15 Updated by laforge 10 months ago

#16 Updated by msuraev 8 months ago

Tested with dynamic TS - same results as with static config.

#17 Updated by msuraev 8 months ago

  • Related to Feature #1648: Verify Multi-TRX support for osmo-bts-trx added

#18 Updated by msuraev 8 months ago

  • Related to Feature #1526: Acquire/update timing advance (TA) added

#19 Updated by msuraev 7 months ago

Gerrit 2859, 2654, 2673 are merged. This does not fix the issue but should make debugging it easier.

#20 Updated by msuraev about 2 months ago

#21 Updated by msuraev 5 days ago

  • Related to Bug #1532: Increased number of poll timeouts on shared PDCHs added

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