Plan PCI at (05) easy steps with Atoll !!
You are looking to plan PCI for your LTE cluster ? do not get in panic and here is the (05) steps to do that in Atoll !
›The Physical Cell Identity is an essential configuration parameter of a radio cell in LTE and It identifies the cell in cell search. The main objective of PCI planning is to ensure that all cells are correctly identified.
›There are 504 physical cell identities.
›These are made up of :
–168 cell identity groups with 3 identities each
–168×3=504 physical cell identities
–PCI =Sub Cell ID + 3 x Cell ID Group
- Create your LTE project
In simple two click paste your site / Transmitter data into Atoll. It should include basic information like Site latitude, longitude, antenna, Azimuth, tilts, antenna height and power. At least make sure that the site coordinate, Azimuths and antenna height are correct.
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2. Core area definition
Create the focus zone (core area) which is the area we want to plan PCI or change the existing PCI Plan ! it is showing in "green color" polygon. Make sure that buffer area (remaining cells) are having an existing PCI plan.
3. Neighbor list planning
To avoid assigning the same PCI plan within neighbors of the cells, it is recommended to create your neighbor plan prior running the PCI Plan!.
Below figures illustrate the steps to create the neighbor plan.
An Example of recommended setting is showing below. Hit the button "Calculate" .. the neighbor are calculated as shown in below figure. If happy then, commit the change.
Check quickly the neighbor plan and that can be performed as showing in below figu:
4. Run PCI Planning
Before running the PCI, need to set PSS & SSS ID Status to "Not Allocated".
"Not Allocated" : Any PCI can be modified without any cost.
"Allocated" : the PCI is modifiable only if absolutely necessary.
"Locked" : The PCI not modifiable.
Time to run the PCI Plan. Following figure is showing how to do that !
Mainly and depends on site to site distance, the reuse distance can be set accordingly. In Rural area the PCI reuse distance can be set to higher value.
As the reference Signal (RS) position in the Resource Block (RB) is decided by the output of PCI mod 6, it is good to put some wight for PCI mod 6 and for PCI Mod 30 (UL DMRS).
Also, it is important to check what is the current PCI step used by the operator and if it is fresh PCI planning , I recommend to use PCI Step 8
There are two type of Pci planning steps:
Non-shifted: PCIi mod 6 same for all cells within the site
Shifted: PCIi mod 6 different for all cells within the site
Below are some example of RS shifted and no shifted scenario:
STEP 1: shifted + same PCI group within site
Example: CI (PSS) = 0,1,2; PCI Group (SSS) = 10
10x3 + 0 = 30
10x3 + 1 = 31
10x3 + 2 = 32
STEP 6: non-shifted + different PCI group within site
Example: CI (PSS) = 1; PCI Group (SSS)= 3,5,7
3x3 + 1 = 10
5x3 + 1 = 16
7x3 + 1 = 22
STEP 8: shifted + different PCI group within site
Example: CI (PSS) = 1,0,2; PCI Group (SSS) = 3,6,8
3x3 + 1 = 10
6x3 + 0 = 18
8x3 + 2 = 26
In PCI Step 1 & 8, the PCI mod 6 is different for all cells within a site.Basically in non-shifted RS, the RS in adjacent cells will cause the situation that the RSs will interfere only each other and in shifted RS, the RS will cause interference on PDSCH resource element.
Once all is set, hit the "start" button.. the PCI plan will run and changes are showing in blue color. Once completed , "Commit" the change.
5. PCI Plan output check
Use Atoll Audit module to calculate the different collision reuses and the main reuses to be checked is "Physical Cell ID Collision" and the "PCI Mod 6 Collision" with small reuse distance.
Below figure is showing an audit report calculated for the same cluster. For example some cases with PCI Mod 6 collision within 138 m which need to be checked if the sectors are looking to same direction !
Thanks for reading !
Source: https://www.linkedin.com/pulse/plan-...rachid-lamali/
Re: Plan PCI at (05) easy steps with Atoll !!
can the atoll build interference matrix based on measurements collected from enodebs (sig logs) ?
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Re: Plan PCI at (05) easy steps with Atoll !!
Hi!
A very good article "PCI Plan in Easy Steps with an Atoll!" was published by Hussam.
I want to expand the article. Download the PCI Plan in Simple Steps with the Atoll in pdf format here: Attachment 43542
Re: Plan PCI at (05) easy steps with Atoll !!
Is there any tool to plan PCIs on mapinfo??
