8/13/2019 KPI improvment in 3G

1/2

8/13/2019 KPI improvment in 3G

2/2

Call set-up

failure

The PrxTotal level is significantly higher than

expected in no/low load conditions.

In case of MHA is used in BTS check MHA an

cables loss parameters, otherwise PrxTotal

value will be too high.

Call dropMHA settings should be checked, see more

in reference [7]

(If MHA parameter is set to ON, Cable loss

parameter is used, Cable loss = Real MHA ga

= Feeder loss parameter)

Call set-up

failureCall drop

Set parameters so that reselection process w

start earlier:

Qqualmin, Sintrasearch and Qhyst2 as per

latest recommendation [8]

Use smaller value N312 (2, recommendation

4).

Use Actix for checking the call set-up delay (L

messages).

Use call set-up time optimisation feature

Dynamic setting of ActivationTimeOffset

(possible in RAN1.5.2 ED2) enables 200 to

500ms reduction for set up delay.

Dropped

call

SHO to wrong cell

will cause drop call.

Overshooting cell come temporarily into

active set and forces a suitable serving cell to

be dropped out. Later RSCP suddenly drops

in the wrong cell and causes a dropped call

because there is no neighbour defined.

Pan away overshooting cell if it is too close to

the serving cell, otherwise apply down tilting a

well.

Use cell individual offset (negative value)

parameter to balance the DL and UL coverag

Check traffic direction of in-car UEs to decide

which cell requires offsets.

Use cell individual offset (positive value)

parameter to balance the DL and UL coverag

Note: Cell individual offsets are not taken into

account when calculating the added cell Tx

power.

Use cell individual offset (positive value)

parameter to balance the DL and UL coverag

Note: Cell individual offsets are not taken into

account when calculating the added cell Tx

power.

Delete unnecessary neighbours.

Improve dominance.

Dropped

call

Round the corner

effect

The call drops due to too rapid CPICH

coverage degradation for Cell A, and

therefore there is not enough time for SHO.

Dropped

call/SHO

failure

Too many

neighbours

n area t e num er o com ne

neighbouring cells become more than 31.

HO list is created using RNC algorithm in the

final sta e some of the nei hbours will

Dropped

call

Cell suffering from

UL interference = DL

(CPICH) coverage

much bigger than ULcoverage

As the UE Tx power is not enough for target

cell synchronisation, the SHO fails which will

cause call drop later.

Dropped

call

DL CPICH coverage

< UL coverage

Cell with lower CPICH power than the

surrounding is having too good UL

performance, as this cells UL cannot be

used efficiently due to SHO is decided upon

DL (CPICH Ec/No).

Cell set-up

failure

Bad RRC connection

set-up success rate

due to slow Ue cell

reselection

RRC connection set-up complete message

not heard by BTS.

Long call

set-up

ime

Long time interval for

sync between RNC

and BTS before

connection

The value of Parameter N312 is too high:

maximum number of in sync indications

received from L1 during the establishment of

a physical channel

High PrxToatal due

to wrong MHA

settings

High Prxtotal due to

Installation problems

The PrxTotal level is significantly higher than

expected in no/low load conditions.

Check the antenna installation as the last

alternative in high PrxNoise case.