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Bug #3395

Uplink CS/MCS control is broken osmo-pcu is used with osmo-bts-trx/osmo-trx

Added by ipse 5 months ago. Updated 4 months ago.

Status:
New
Priority:
Normal
Assignee:
-
Target version:
-
Start date:
07/14/2018
Due date:
% Done:

0%

Spec Reference:

Description

Not sure which project to assign this to.

GprsMs::update_cs_ul() function (osmo-pcu/src/gprs_ms.cpp) is used to control the UL CS/MCS mode and in its current implementation is relies on the Quality "Q" value reported by L1. Osmo-trx does not really calculate the SNR of the link and thus osmo-bts-trx always report Q as 0. This misleads the current algorithm which always drops the CS/MCS to the lowest possible mode (CS-1/MCS-1).

Possible solutions I see:
1) Use another metric, like BER which are reported by osmo-bts-trx. A similar method is already used by the DL CS/MCS control.
2) Implement SNR calculation in osmo-trx. A better way, but much more involved.


Related issues

Related to OsmoBTS - Bug #1616: osmo-bts-trx / osmo-bts-octphy doesn't provide C/I information to PCU Stalled2016-02-23

Related to OsmoBTS - Bug #1855: provide actual BER or C/I values from osmo-bts-trx into the PCUNew2016-11-18

History

#1 Updated by laforge 5 months ago

this is not an osmo-pcu bug, but an osmo-bts-trx bug. It doesn't compute/fill-in all the values of the primitives at the PCU socket. See #1616 from two years ago, and #1855 from one year ago.

#2 Updated by laforge 5 months ago

  • Related to Bug #1616: osmo-bts-trx / osmo-bts-octphy doesn't provide C/I information to PCU added

#3 Updated by laforge 5 months ago

  • Related to Feature #1815: tool for building binary ipk from .list/.control added

#4 Updated by laforge 5 months ago

  • Related to deleted (Feature #1815: tool for building binary ipk from .list/.control)

#5 Updated by laforge 5 months ago

  • Related to Bug #1855: provide actual BER or C/I values from osmo-bts-trx into the PCU added

#6 Updated by laforge 5 months ago

on a more general notice, see https://osmocom.org/versions/122 for the various known issues of osmo-bts-trx compared with other osmo-bts-* variants.

#7 Updated by laforge 4 months ago

#8 Updated by laforge 4 months ago

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