Scrambling Code Planning

[Processor]

Hello Guys,

I'm on a new project and planning the scrambling code for the entire network, however, i need some support/help from all professionals here already working on UMTS network.

First, is there any particular order/pattern in allocating PSC...the reason i'm asking is that a friend was saying something about 2 different PSC being able to clash based on some calculations i couldnt understand.

Also, is there a way i could automatically plan the PSC and neighbours using ATOLL?

My plan is as below, a set of 3 vertical codes for each site (i.e 0,3,6);

0 9 18.........
3 12 21.........
6 15 24.........

2 10 19.........
4 13 22.........
7 16 25.........

Please any ideas or better way of planning?

[lejun]

Hello Guys,

I'm on a new project and planning the scrambling code for the entire network, however, i need some support/help from all professionals here already working on UMTS network.

First, is there any particular order/pattern in allocating PSC...the reason i'm asking is that a friend was saying something about 2 different PSC being able to clash based on some calculations i couldnt understand.

Also, is there a way i could automatically plan the PSC and neighbours using ATOLL?

My plan is as below, a set of 3 vertical codes for each site (i.e 0,3,6);

0 9 18.........
3 12 21.........
6 15 24.........

2 10 19.........
4 13 22.........
7 16 25.........

Please any ideas or better way of planning?
Hi friend,

We use Asset for SC Planning (you need plan neighbor list first, Planning tool will use this neighbors plan and the distance to assign SC). I think Atoll have automatic SC Planning too.

It is easy (like BSIC Planning in GSM) :D

In WCDMA we have 512 really different code so it is easy (not as same as CDMA2000, codes differ the other by phase, more difficult).

I see some guys (especially in Huawei) use pattern, but i think it is more complex and waste time ;)

Regards

[_lisi4king]

Hello Guys,

I'm on a new project and planning the scrambling code for the entire network, however, i need some support/help from all professionals here already working on UMTS network.

First, is there any particular order/pattern in allocating PSC...the reason i'm asking is that a friend was saying something about 2 different PSC being able to clash based on some calculations i couldnt understand.

Also, is there a way i could automatically plan the PSC and neighbours using ATOLL?

My plan is as below, a set of 3 vertical codes for each site (i.e 0,3,6);

0 9 18.........
3 12 21.........
6 15 24.........

2 10 19.........
4 13 22.........
7 16 25.........

Please any ideas or better way of planning?

Hello, we use like:

10,11,12

13,14,15

and so on.

From 0 to 9 for indoor sites. No need to use Atoll for indoor planning, easy to choose one from set 0-9 PSC

:cool:

[dekili]

Who's equipment is in question? In general, it is recommended to use as lower number of code groups and as much as possible codes inside the group to make cell search time shorter as possible and not to use all codes because of future upgrades and new sites...

[rffreeconsult]

Unlike CDMA which is synchronous system. UMTS (WCDMA) is asynchronous and all the SC code are pseudo-orthogonal to each other. Therefore, you can use a random assignment for SC planning among the 512 primary SC (Ex: sector A's SC = 3, sector B's SC= 4 and sector C's SC=8 still work without any clash or SC collision.

A test I have done for a first-tier vendor on the behalf of a big operator has shown no difference between planning by code group (8 SC for a group) and random assignment. by confidentiality, the names can not be told here. But you can use random assignment. The SC-code group is aimed to speed up SC decoding for the UE but now with powerful processing capacity, the decoding time is minimal.

The operators, usually with conservative method inherited from TDMA/GSM system still prefers to have SC group...But in reality, it doesn't change much

[lejun]

Unlike CDMA which is synchronous system. UMTS (WCDMA) is asynchronous and all the SC code are pseudo-orthogonal to each other. Therefore, you can use a random assignment for SC planning among the 512 primary SC (Ex: sector A's SC = 3, sector B's SC= 4 and sector C's SC=8 still work without any clash or SC collision.

A test I have done for a first-tier vendor on the behalf of a big operator has shown no difference between planning by code group (8 SC for a group) and random assignment. by confidentiality, the names can not be told here. But you can use random assignment. The SC-code group is aimed to speed up SC decoding for the UE but now with powerful processing capacity, the decoding time is minimal.

The operators, usually with conservative method inherited from TDMA/GSM system still prefers to have SC group...But in reality, it doesn't change much

Yes, i plan as your method (random assignment) and performance is good :D

Regards

[marko]

there is an Atoll plugin that does automatic code planning (ACP) and it generates automatically your codes for the cells.

[bikplaboi]

Hi,

Many thanks for the great input, do you have a spreadsheet template that you use for your Scramble Code Planning you could share for us..


Thanks,

bikplaboi..



Unlike CDMA which is synchronous system. UMTS (WCDMA) is asynchronous and all the SC code are pseudo-orthogonal to each other. Therefore, you can use a random assignment for SC planning among the 512 primary SC (Ex: sector A's SC = 3, sector B's SC= 4 and sector C's SC=8 still work without any clash or SC collision.

A test I have done for a first-tier vendor on the behalf of a big operator has shown no difference between planning by code group (8 SC for a group) and random assignment. by confidentiality, the names can not be told here. But you can use random assignment. The SC-code group is aimed to speed up SC decoding for the UE but now with powerful processing capacity, the decoding time is minimal.

The operators, usually with conservative method inherited from TDMA/GSM system still prefers to have SC group...But in reality, it doesn't change much

[RFDude_PMA]

Hi all

I have used both and definitively they all work, but the problem comes when there is high density of sites. With random you need to be carefull not to assign the same sc to a second or third neighbor cell. Drop connections start to increase.
So depending on the scenario the best approach is the create polygon and form groups of cells and create a plan with a spare capacity.

The problem is when the network grow and you have IRATs relations created.. To re-organized every thing is like a surgery, every detail counts.

As a expert wrote in this forum, the assignment work 1,2,3 or 8,16,32 bcz they are pseudo-orthogonal codes. The issue is to plan for future to avoid colisions.

Best Regards

[Processor]

Please does anyone have any PSC plan templates?

[jjkjjk]

Hi All,

You can find ScrCodes group Definition at 3GPP TS25.313 section 5.2.3; 512 SCs are divided into 8 groups(64 each)
What I applied the subgroup is 0,1,2 for site1, 3,4,5 for site2,... until 60,61,62; You have SC=63 spared for joker, Femto etc.; Similarly for Group2 SC from 64 to 126 with 127 as joker; And do so for group3-8 with SC=191,255,319,383,447,511 as jokers.
In your country border area, remember to the preferential SCs and Non-preferential SCs, check also 3GPP TS25.313 to figure out which groups is your countrys preferentials.

Best regards