164847546 Call Drop Diagnoses in LTE Network

LTE Call drop diagnoses

LTE Call drop diagnoses

Huawei Technologies Co., LTD

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Version

Description

Author

 

202!"ov0#

V.00

Dra$t

Ah%ed Awwad

LTE Call drop diagnoses

Content i. ii. iii. iv. v. vi. vii.

LT& call drop calculation $or%ula Call drop sudden increase diagnoses 'u( counters to de$ine the call drop reasons Traces to chec) the CHR data during the call drop Log $iles analysis o$ the call drops Call drop reasons $ro% the drive test logs How to e*port +RDlogs $or $urther analysis

A. Summary

LTE Call drop diagnoses

i.

LTE call drop calculation formula

LTE DCR service % = (L.ERA!.A"normRel# (L.ERA!.A"normRel$L.E RA!.ormRel&

L.ERA!.A"normRel = Total num"er of a"normal ERA! releases "y t'e eode! L.ERA!.ormRel = Total num"er of normal ERA! releases "y t'e eode!

Counter D

Counter ame

Counter Description

2#-2-#

L.&!RA+.A(nor%Rel

Total nu%(er o$ a(nor%al &!RA+ releases (y the e"ode+

2#-2--

L.&!RA+."or%Rel

Total nu%(er o$ nor%al &!RA+ releases (y the e"ode+

ii.

Call drop sudden increase diagnoses  Case study

LTE DCR service % = L.ERA!.A"normRel# (L.ERA!.A"normRel$L.E RA!.ormRel&

LTE Call drop diagnoses

iii.

Su" counters to define t'e call drop reasons

)uery t'e "elo* counters to define t'e drop reason

Counter D Counter ame

+,-/-0-1/

L.E RA!.A"normRel.233ut

Counter Description Total num"er of a"normal ERA! releases for outgoing 'andovers

+,-/-0-0-L.ERA!.A"normRel.Radio

um"er of a"normal ERA! releases due to faults at t'e radio net*or4 layer 

+,-/-0-05L.ERA!.A"normRel.TL

um"er of a"normal ERA! releases due to faults at t'e transport net*or4 layer 

+,-/-0-01L.ERA!.A"normRel.Cong

um"er of a"normal ERA! releases due to net*or4 congestion

+,-/-0-6+

L.E um"er of a"normal ERA! releases due to 'andover RA!.A"normRel.237ailure failures

+,-/-0-6-L.ERA!.A"normRel.88E

um"er of a"normal ERA! releases due to faults in t'e E9C

LTE Call drop diagnoses

-

7rom t'e grap' *e can see t'at t'e main reaon "e'ind t'is 'ig' call drop rate (6 %&

during -/t' :une is due to radio ("lue& ; 2andover failures (green& .

iv.

Traces to c'ec4 t'e C2R data during t'e call drop

RSR9 is around +?d!m> t'is is an area *'ere easily can 'ave a drop.  And t'at emp'asi@e t'e result *e got in step 5 *'en *e catc' t'e drop reason is due to radio. .

v.

Log files analysis of t'e call drops

send DT to t'e pro"lematic area Analy@e log files

LTE Call drop diagnoses

vi.

Call drop reasons from t'e drive test logs 9ro"lem  +  Call Drop#2.3 7ailure B eig'"or 8issing 9C=//  1+1&

-

7rom t'e "elo* R7 ta"le *e can see t'e missing neig'"or

-

9C 1+1 'as muc' "etter signal t'an t'e serving 9C // > "ut due to t'e missing neig'"or pro"lem > t'e E 'as not 'andover to it.

LTE Call drop diagnoses

9ro"lem  -  Call Drop due to timer t5?1 epire 

•

2andover fail due to t5?1 timeout F 

(T5?1G e! sent 2andover Command> t'en did not receive 2andover Complete from E in a certain period more t'an t5?1 time > so t'is time epires&

•

E setup a Reesta"lis'ment reHuest due to 'andover fail.

•

Reesta"lis'ment fail > t'en t'e call drops .

LTE Call drop diagnoses

vii.

2o* to eport !RDlogs for furt'er analysis

7or furt'er analysis > eport t'e !RDlog file ; anali@e C2R data

-

RUN the MML command as seen above and export the BRDLOG file

-

Hint (need customer approval as it contains used information

C. Summary This docu%ent (rie$ly descri(ed the %ost i%portant steps to diagnose the LT& call drops , it can help the opti%i/er to put hand on the issue o$ the drop.