Bug 2988

Summary:	Wrong L3 filtering formula used for UL power control
Product:	ns-3	Reporter:	Zoraze Ali <zorazeali>
Component:	lte	Assignee:	Biljana Bojović <bbojovic>
Status:	RESOLVED FIXED
Severity:	normal	CC:	gawlowicz.p, mmiozzo, ns-bugs
Priority:	P3
Version:	ns-3-dev
Hardware:	All
OS:	All
Attachments:	Initial patch

Description Zoraze Ali 2018-09-05 06:37:17 UTC

Hi, 

In LteUePowerControl::SetRsrp function the formula used to apply L3 filtering is incorrect. The code is the following:

m_rsrp = coeff * m_rsrp + (1 - coeff) * value;

As per the formula mentioned in the standard and in ns-3 documentation (https://www.nsnam.org/docs/models/html/lte-design.html#performing-measurements) it should be:

m_rsrp = coeff * value + (1 - coeff) * m_rsrp;

Moreover, a hard-coded coeff = 0.7 is used for L3 filtering. I think we should use the same coefficient value as in UE RRC, which is sent by an eNB in RRC connection reconfiguration message.

Kind regards,
Zoraze

Comment 1 Zoraze Ali 2018-09-05 06:40:08 UTC

Created attachment 3179 [details]
Initial patch

Attached is the initial patch.

Comment 2 Biljana Bojović 2018-09-05 09:29:13 UTC

Regarding formula OK. 

Regarding filtering, I would prefer that Marco or someone of the original authors confirms.

Comment 3 Marco Miozzo 2018-09-05 09:33:26 UTC

We already had a discussion, I'm fine with the patch.

Comment 4 Zoraze Ali 2018-09-07 08:18:45 UTC

Pushed to changeset 13797:c44705634f6f