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Bug #1524

PACCH on the wrong timeslot

Added by zecke over 2 years ago. Updated 7 days ago.

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

0%

Estimated time:
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 osmopcu-1.log 8.22 KB msuraev, 02/24/2016 03:44 PM
osmopcu-2.log osmopcu-2.log 101 KB msuraev, 02/24/2016 05:00 PM
pcu.pcapng.gz pcu.pcapng.gz 1.27 MB msuraev, 02/25/2016 10:32 AM
debug.log debug.log 2.35 MB msuraev, 02/25/2016 10:32 AM
osmopcu-3.log osmopcu-3.log 8.94 KB Log from mediatek MT6580M based MS matt9j, 07/10/2018 05:02 AM

Related issues

Related to OsmoBTS - Bug #1795: osmo-bts-trx: fails to assign second lchan on TCH/H TSClosed2016-08-09

Related to OsmoBTS - Feature #1648: Verify Multi-TRX support for osmo-bts-trxClosed2016-03-11

Related to OsmoPCU - Feature #1526: Acquire/update timing advance (TA)Stalled2016-02-22

Related to OsmoPCU - Feature #2709: use osmo_fsm for TBFNew2017-12-05

Related to OsmoPCU - Bug #1532: Increased number of poll timeouts on shared PDCHsNew2016-02-22

Related to OsmoPCU - Bug #1759: Wrong calculation of DL window size for DL assignmentStalled2016-06-28

History

#1 Updated by zecke over 2 years ago

  • Assignee set to msuraev

#2 Updated by msuraev over 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 over 2 years ago

  • Status changed from New to In Progress

#4 Updated by msuraev over 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 over 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 over 2 years ago

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

#7 Updated by msuraev over 2 years ago

Bigger and cleaner log for reference.

#8 Updated by msuraev over 2 years ago

Attaching latest logs.

#9 Updated by msuraev over 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 over 2 years ago

The config change above makes acer phone work albeit slow.

#11 Updated by laforge about 2 years ago

  • Status changed from In Progress to New

#12 Updated by msuraev over 1 year ago

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

#13 Updated by laforge over 1 year ago

  • Priority changed from Normal to High

#14 Updated by msuraev over 1 year ago

  • Status changed from New to Stalled

#15 Updated by laforge over 1 year ago

#16 Updated by msuraev about 1 year ago

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

#17 Updated by msuraev about 1 year ago

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

#18 Updated by msuraev about 1 year ago

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

#19 Updated by msuraev about 1 year ago

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

#20 Updated by msuraev 7 months ago

#21 Updated by msuraev 6 months ago

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

#22 Updated by msuraev 5 months ago

  • Related to Bug #1759: Wrong calculation of DL window size for DL assignment added

#23 Updated by laforge 5 months ago

  • Assignee changed from msuraev to sysmocom

#24 Updated by laforge 3 months ago

  • Assignee changed from sysmocom to lynxis

#25 Updated by matt9j 19 days ago

I am able to reproduce this issue reliably with two MS's in my possession, a Lenovo A319 and a BLU Dash 3.5(Mediatek MT6572M). I see similar behavior between my SDR setup osmo-pcu(0.5.0.9.3df1), osmo-bts-trx(0.8.1.20.0257), and osmo-trx-uhd(4.9.2; Boost_105500; UHD_003.009.005) and an embedded setup based on a Nuran Litecell 1.5 osmo-pcu(0.2.0.936-85cf), and osmo-bts-lc15(0.4.0.566-eb5b7). lynxis please let me know if there is any prototype testing or debug I can do to aid your development.

#26 Updated by matt9j 7 days ago

I was also able to test with a newer mediatek phone, and the issue still persisted. Log attached.

Phone: Gionee P5-Mini
Released: April 2016
Chipset: Mediatek MT6580M

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