Move traffic from 900 to 1800 band

**aznax** · 2012-04-12, 08:58 PM

Hello Everybody,
i need you help in order to change some parameters on Nokia equipments.
i have 900 1800 cells in my assigned region and there are many 900 band cells congested.

for example:
900 band - 2 TRX takes 20 erlang Traffic but
1800 band - 3 TRX takes 5 erlang traffic

i have enabled umbrella cells on 900 band and changed parameter like following

From Source cell (900) to target cell (1800) hoLevelUmbrella -90 dbm

i changed this parameter on 10 different sites.
on some of them i succeed to move traffic to 1800 band but some are failed.
Do you recommend to change some other parameters as well?
like as
hoMarginDelayTime
hoMarginLev
hoMarginPbgt
hoMarginQual
hoPriorityLevel
hoTargetArea

and so on?

Thanks in advance

**Finetopix** · 2012-04-12 08:58 PM

**black dark** · 2012-04-13, 06:27 PM

As far as i know it's beter to you to set those parameters to change load traffic between FR and HR TRX
btsSpLoadDepTchRateLower
amrSegLoadDepTchRateUpper
btsSpLoadDepTchRateUpper
amrSegLoadDepTchRateLower

**Justradio** · 2012-04-14, 03:21 PM

You can change the parameter for level, quality and pbgt to ease the handover from GSM to DCS, while DCS to GSM just make it hard.
but please consider the ACL value.
Maybe in DCS, u can consider c2 value as well. If the GSM TA serving is near then it will help to reduce the trafic.
As the MS will camp to the DSC more compare to GSM.

**plannerguy** · 2012-04-20, 02:10 AM

Hi

i think us hould modify the LAR (Layer acess threshold)and LER (Layer exit threshold) thresholds

Regards
Plannerguy

**trongcongbk** · 2012-05-13, 03:56 PM

Did you change parameters in IDLE Mode??? Cell reselection offset (REO), Penaty Time (PET)???

**ashraferto** · 2012-05-14, 02:41 PM

you also can increase the CRO for 1800 to force the MS camping on it

**aznax** · 2012-05-14, 04:38 PM

Hello evrybody,
i have changed CREselection offset for 1800 band, put higher value, and later enabled umbrella cell and put HOM umbrella -90, it caused ping pong handover firstly
but later i changed PBGT HOM from 1800 to 900 in order to reduce handover attempt back to 900 which solved the problem totally.
thanks

**ashraferto** · 2012-05-15, 01:43 AM

Originally Posted by aznax

Hello evrybody,
i have changed CREselection offset for 1800 band, put higher value, and later enabled umbrella cell and put HOM umbrella -90, it caused ping pong handover firstly
but later i changed PBGT HOM from 1800 to 900 in order to reduce handover attempt back to 900 which solved the problem totally.
thanks

you welcome anytime

**fantominox** · 2012-05-16, 06:44 AM

Hi aznax,
Level for Umbrella HO is OK and decreasing it more you can cause ping pong HO (check HO parameters)
I met this problem in my network after DCS implementation as capacity layer in urban area.
Solving occured simple: more tilt for DCS.
If you have the same tilt for 900 and 1800 or tilt for 900 is bigger, then close to site DCS level is low because antenna pattern for DCS is more flat in comparison to GSM pattern, and you should remember that DCS singal fades faster than GSM.
Try, in my network this increased traffic in DCS.

BR
Fantominox.

**makeev** · 2012-05-22, 07:50 PM

Try using NBL Retuning. Change nonbcchlayeroffset to 6 or 4 for your 1800 trx and also make the access and exit thresholds more friendly for 1800 shifting.