LAC split "How"

[justdream]

Dears,

Capacity Team has recommended to split LAC in my BSC as paging has increased..
BSC already has only 1 LAC
My task to split this LAC into 2


Could you guide me, how to do it practically?

[s52d]

Dears,

Capacity Team has recommended to split LAC in my BSC as paging has increased..
BSC already has only 1 LAC
My task to split this LAC into 2


Could you guide me, how to do it practically?

1. create new LAC in the the VLR/MSC, also RA in SGSN (it is LA-RA, so every new LA is also new RA)
2. check if there are any special settings due to national roaming, billing etc
3. move one test site into new LAC and test (change CGI in the BSC, change cell definition in the MSC/VLR)
4. test services, test billing etc for this test site
5. split BSC area into two, by minimising handovers between two halves (prepare lis of cells)
6. execute by changing CGI in cell definiton in the BSC/MSC etc
7. monitor KPIs

Assuming there are no UTRAN/eUTRAN system to synchronize, otherwise do it in paralell

BR
s52d

[justdream]

5. split BSC area into two, by minimising handovers between two halves (prepare lis of cells)
BR
s52d

Thanks friend, Above point (no. 5)
Is the most important - so please advcie how to do it?
Which counters/ KPIs could be used?
then should I draw over MapInfo?

sorry, but I didn't get the idea
Thanks

[s52d]

Thanks friend, Above point (no. 5)
Is the most important - so please advcie how to do it?
Which counters/ KPIs could be used?
then should I draw over MapInfo?

sorry, but I didn't get the idea
Thanks

I take number of handovers between cells for a decent day.
Then: merge cells into sites and recount handovers (so, siteA-cellA to siteB-cellA and siteA/cA to sB/Cb sum up to siteA-siteB)
then, cluster sites with high number of handovers (small cities, close sites with a lot of overlapping/handovers)
into "virtulal" sites. Then try few scenarios, how to assign LA to those clusters.

Practically, I use one text file with handover statistics, and one file with cell-LA matching.
With one 100 lines long program I just make LA-LA statistics for every scenario, as well as cell-LA for every cell/site.
When cell has more handovers to foreign LA is for own LA, it is moved to this new LA.

Ah, once we just looked into the map and draw LA line where we assumed minimum handovers/overlapping.
It worked well.

BR
s52d

[chronix_ray]

Dears,

Capacity Team has recommended to split LAC in my BSC as paging has increased..
BSC already has only 1 LAC
My task to split this LAC into 2


Could you guide me, how to do it practically?

Are you in a planning, optimization or operations team? Actually it depends on your role.

As planner, you should dimension your LA geographically. Separate the sites based in Traffic Erlang which gives high paging load. Also check your highways/roads/streets which gives you handover kpi and also affects your LA dimensioning.

Kindly refer to attached file for your reference.

Br// King

[juanpico]

Dears,

Capacity Team has recommended to split LAC in my BSC as paging has increased..
BSC already has only 1 LAC
My task to split this LAC into 2


Could you guide me, how to do it practically?

Hi justdream

this is a fast approach: LA size require some assumptions regarding the traffic and subscriber behavior. In order to estimate the maximum size of a LA, an estimated paging load per Erlang of traffic in the LA is calculated.

1. Do a site count of the exisiting bsc (1 lac), cell count, trx count, total daily tch traffic (in Erlang), and peak tch traffic.
2. Divide the no. of site (into 2 lac) by dividing the total daily tch traffic into halves. not necessarily 50-50, it may be 60-40, or 65-35 again depending on the number of tch traffic
3. Once you have halves the traffic per day let say you have 100 sites (LAC1=60 sites / LAC2=40 sites), plot the sites in map and project the main road. look into details of road making sure the you don't cut the main road in parallel instead do it perpendicularly. avoid also cutting the main intersection where great no of handover can occur since it is a busy part of the road.

Regardless of the type of area, rural or urban, it is recommended to have the LA border cells in low subscriber density area. LA borders crossing over high mobility areas, e.g. high ways, should be avoided. The most important recommendation is to carefully monitor the performance of the system.

[Prokopyo]

Hi justdream

this is a fast approach: LA size require some assumptions regarding the traffic and subscriber behavior. In order to estimate the maximum size of a LA, an estimated paging load per Erlang of traffic in the LA is calculated.

1. Do a site count of the exisiting bsc (1 lac), cell count, trx count, total daily tch traffic (in Erlang), and peak tch traffic.
2. Divide the no. of site (into 2 lac) by dividing the total daily tch traffic into halves. not necessarily 50-50, it may be 60-40, or 65-35 again depending on the number of tch traffic
3. Once you have halves the traffic per day let say you have 100 sites (LAC1=60 sites / LAC2=40 sites), plot the sites in map and project the main road. look into details of road making sure the you don't cut the main road in parallel instead do it perpendicularly. avoid also cutting the main intersection where great no of handover can occur since it is a busy part of the road.

Regardless of the type of area, rural or urban, it is recommended to have the LA border cells in low subscriber density area. LA borders crossing over high mobility areas, e.g. high ways, should be avoided. The most important recommendation is to carefully monitor the performance of the system.

I agree with juanpico especially about the geographical aspect of doing a LAC split. This is a straight forward way of doing a LAC split. Basically, you are setting your border where you avoid Location Area Update in fast moving areas.

Avoid having your border in parallel with major highways and roads with high mobility. If for any reason you have to set your border parallel to a major road, try putting it as far as possible (e.g. 2-3 sites away). This will minimize the effect of having to do LAC update every time cars/users pass along the border.

[gprastomo]

Hi My friend,

You re as Planning and Opti team has task to choose the site to be included in those 2 LACs.
So what you need to do is, to calculate all possibilities that by dividing the LAC in tot 2 LACs you will have good paging load (around 20%-30%). Basically the LAC will be splitted if the Paging Load reach 60%, or more. Sometime its better to keep around 200k paging/hour.
What we need to do is to find the paging message per cell then you can find the best LAC split. If you put 2 LACs but the predicted paging message still much more than 200k paging/hour so you need to put 3LACs.

[justdream]

[QUOTE=gprastomo;157982]
What we need to do is to find the paging message per cell then you can find the best LAC split.[QUOTE]

Thanks, please share how to calculate Paging per cell :-)

[s52d]

[QUOTE=justdream;158007][QUOTE=gprastomo;157982]
What we need to do is to find the paging message per cell then you can find the best LAC split.

Thanks, please share how to calculate Paging per cell :-)

Hi!
Some vendors provide statistics. Look at per LA/RA counters in the BSC/RNC.
For LA planning you can assume it is same for every cell ine the LA (it is simmilar, in fact).

br
s52d