Iphone4 Cause High RTWP Issue 20110328 v0.1

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April 17, 2023

Iphone 4 cause high RTWP Issue

Content

Problem description Root cause analyze solution Suggestion

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential

Problem Description Iphone 4 cause abnormal high RTWP during call release

procedure.

Figure1:High RTWP caused by Iphone4 during call release


Root cause analyze(1)

RRC connection release procedure Introduction

UE UTRAN

RRC CONNECTION RELEASE

RRC CONNECTION RELEASECOMPLETE

Figure 8.1.4-1: RRC Connection Release procedure on the DCCHFigure 8.1.4-1: RRC Connection Release procedure on the DCCH


Root cause analyze (2)

UTRAN

RRC connection release procedure details(UE side)

UE

RRC Connection Release

RRC Connection Release Complete

T308(40ms)


After receive RRC connection Release message UE will:1,Initialise the counter V308 to zero2,Send RRC Connection Release Complete message3,Start timer T308

UE delete radio link RRC connection release procedure finished

After T308 expired ,if V308<=N308,UE need send RRC connection Release completer message again

T308(40ms)

T308: Start at Transmission of RRC CONNECTION RELEASE COMPLETE, Not stopped N308 :Maximum number of retransmissions of the RRC CONNECTION RELEASE COMPLETE message V308 : Upon expiry of T308 When V308 > N308 the UE stops re-transmitting the RRC CONNECTION RELEASE

COMPLETE message.



UTRAN

UE



T308 T308


If RRC connection Release complete received correctly ,RAN delete radio link at this time

1,No TPC command send to UE from Network side after radio link deleted , 2,UE still need send message during this period according to 3GPP spec,

RRC connection release procedure details(UTRAN side)

UE delete radio link



UTRAN

UE



T308 T308


During this period ,because there are no TPC command from network ,Iphone 4 may have problem with inner loop power control ,that cause RTWP increased high value in a very short time (eg.40ms ,UE TX Power can increase 60dB)

Iphone 4 Problem

If the first RRC connection Release complete received correctly ,RAN delete radio link at this time


Solution

UTRAN make a delay for release the radio resource during RRC

connection release procedure ,to make Iphone 4 inner loop

power control work normally

UTRAN

UE



T308 T308


After RRC connection Release complete received correctly ,UTRAN don’t delete radio link at this time

UTRAN delete radio link after UE released

UE delete radio link

Delay


Suggestion According to the analyze above ,Iphone 4 will cause

abnormal high RTWP during call release procedure. A patch of NodeB is ready to resolve this problem, and

the verification test shows that the RTWP is normal

when Iphone4 release the call We propose to apply this patch for several sites to verify

this problem on live network ,this Friday morning (2011-

04-01)

Upgrade Sites information already provided

Iphone4 Cause High RTWP Issue 20110328 v0.1

Documents

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