hussam
2022-06-01, 05:43 PM
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.
https://media-exp1.licdn.com/dms/image/C5112AQFu_IqJur5DMA/article-inline_image-shrink_1000_1488/0/1580464186080?e=1659571200&v=beta&t=qRZAHoeK7V890EycVAvkx_wEiUVaP7mnTA8Rp2z2m8s
https://media-exp1.licdn.com/dms/image/C5112AQEZNtsdRDxLPw/article-inline_image-shrink_1000_1488/0/1580464193611?e=1659571200&v=beta&t=1i-BypXomT5iz0agq_Oiv0Xhflg5bn2bp1rvQ4EnbYw
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.
https://media-exp1.licdn.com/dms/image/C5112AQFIr-iJg7zL0A/article-inline_image-shrink_1000_1488/0/1580464320217?e=1659571200&v=beta&t=N12-xocDQDkfAgWUtxGb0ykRy5emguHmsGUJLzWYoXw
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.
https://media-exp1.licdn.com/dms/image/C5112AQG9IwMTiBl77g/article-inline_image-shrink_1000_1488/0/1580464532962?e=1659571200&v=beta&t=OOnC2cqrH843WA_JkxninKRkHPtpc3y9-azPl9S5wTc
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.
https://media-exp1.licdn.com/dms/image/C5112AQGvJQ3pWhbjBA/article-inline_image-shrink_1500_2232/0/1580465124111?e=1659571200&v=beta&t=PMao0Pxpn1qy0NCMEEdK0ZmzjCr6xQymJtc0hn5oOIM
Check quickly the neighbor plan and that can be performed as showing in below figu:
https://media-exp1.licdn.com/dms/image/C5112AQHHCW0R1lko1A/article-inline_image-shrink_1000_1488/0/1580465443051?e=1659571200&v=beta&t=1l-UVR1kD1lmnL49apIkdR3Lpq-HkGCaMW353JYKfVE
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.
https://media-exp1.licdn.com/dms/image/C5112AQGDQuWmuVRuxQ/article-inline_image-shrink_1000_1488/0/1580494783159?e=1659571200&v=beta&t=uFpx7rJ8KPFvXLSAU0hnfV9q36T8TV-wLEcYHK7_U0Y
Time to run the PCI Plan. Following figure is showing how to do that !
https://media-exp1.licdn.com/dms/image/C5112AQHSZIWzpRRVIg/article-inline_image-shrink_1000_1488/0/1580495183659?e=1659571200&v=beta&t=X89N5NXCgBJmCBdjqpXSmgY3obWeIOFkLt4t0vp4-fA
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).
https://media-exp1.licdn.com/dms/image/C5112AQGu60r_qYiI9Q/article-inline_image-shrink_1500_2232/0/1580496897976?e=1659571200&v=beta&t=UBzeuRziJDYCmr4O4qHakQ-BoT6RwK4Vv8GS28h4wEA
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.
https://media-exp1.licdn.com/dms/image/C5112AQGGkFOmjESGvA/article-inline_image-shrink_1500_2232/0/1580496917732?e=1659571200&v=beta&t=WmF__oLQhy_abGhAGISKNuwaeouWhATKxM0WAwzf6JU
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.
https://media-exp1.licdn.com/dms/image/C5112AQHNFEg2GPafKw/article-inline_image-shrink_1000_1488/0/1580505332367?e=1659571200&v=beta&t=Jo058rVDnGsz9bfaqYo-_SuYtOWoQ-_86RpVH9oseZo
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 !
https://media-exp1.licdn.com/dms/image/C5112AQFtsihunyXgHQ/article-inline_image-shrink_1500_2232/0/1580505669507?e=1659571200&v=beta&t=0OUHMpQ2fFotzP4ejHltZNfaoU2LDesan1eaOw4omNc
Thanks for reading !
Source: https://www.linkedin.com/pulse/plan-pci-05-easy-steps-atoll-rachid-lamali/
›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.
https://media-exp1.licdn.com/dms/image/C5112AQFu_IqJur5DMA/article-inline_image-shrink_1000_1488/0/1580464186080?e=1659571200&v=beta&t=qRZAHoeK7V890EycVAvkx_wEiUVaP7mnTA8Rp2z2m8s
https://media-exp1.licdn.com/dms/image/C5112AQEZNtsdRDxLPw/article-inline_image-shrink_1000_1488/0/1580464193611?e=1659571200&v=beta&t=1i-BypXomT5iz0agq_Oiv0Xhflg5bn2bp1rvQ4EnbYw
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.
https://media-exp1.licdn.com/dms/image/C5112AQFIr-iJg7zL0A/article-inline_image-shrink_1000_1488/0/1580464320217?e=1659571200&v=beta&t=N12-xocDQDkfAgWUtxGb0ykRy5emguHmsGUJLzWYoXw
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.
https://media-exp1.licdn.com/dms/image/C5112AQG9IwMTiBl77g/article-inline_image-shrink_1000_1488/0/1580464532962?e=1659571200&v=beta&t=OOnC2cqrH843WA_JkxninKRkHPtpc3y9-azPl9S5wTc
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.
https://media-exp1.licdn.com/dms/image/C5112AQGvJQ3pWhbjBA/article-inline_image-shrink_1500_2232/0/1580465124111?e=1659571200&v=beta&t=PMao0Pxpn1qy0NCMEEdK0ZmzjCr6xQymJtc0hn5oOIM
Check quickly the neighbor plan and that can be performed as showing in below figu:
https://media-exp1.licdn.com/dms/image/C5112AQHHCW0R1lko1A/article-inline_image-shrink_1000_1488/0/1580465443051?e=1659571200&v=beta&t=1l-UVR1kD1lmnL49apIkdR3Lpq-HkGCaMW353JYKfVE
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.
https://media-exp1.licdn.com/dms/image/C5112AQGDQuWmuVRuxQ/article-inline_image-shrink_1000_1488/0/1580494783159?e=1659571200&v=beta&t=uFpx7rJ8KPFvXLSAU0hnfV9q36T8TV-wLEcYHK7_U0Y
Time to run the PCI Plan. Following figure is showing how to do that !
https://media-exp1.licdn.com/dms/image/C5112AQHSZIWzpRRVIg/article-inline_image-shrink_1000_1488/0/1580495183659?e=1659571200&v=beta&t=X89N5NXCgBJmCBdjqpXSmgY3obWeIOFkLt4t0vp4-fA
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).
https://media-exp1.licdn.com/dms/image/C5112AQGu60r_qYiI9Q/article-inline_image-shrink_1500_2232/0/1580496897976?e=1659571200&v=beta&t=UBzeuRziJDYCmr4O4qHakQ-BoT6RwK4Vv8GS28h4wEA
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.
https://media-exp1.licdn.com/dms/image/C5112AQGGkFOmjESGvA/article-inline_image-shrink_1500_2232/0/1580496917732?e=1659571200&v=beta&t=WmF__oLQhy_abGhAGISKNuwaeouWhATKxM0WAwzf6JU
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.
https://media-exp1.licdn.com/dms/image/C5112AQHNFEg2GPafKw/article-inline_image-shrink_1000_1488/0/1580505332367?e=1659571200&v=beta&t=Jo058rVDnGsz9bfaqYo-_SuYtOWoQ-_86RpVH9oseZo
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 !
https://media-exp1.licdn.com/dms/image/C5112AQFtsihunyXgHQ/article-inline_image-shrink_1500_2232/0/1580505669507?e=1659571200&v=beta&t=0OUHMpQ2fFotzP4ejHltZNfaoU2LDesan1eaOw4omNc
Thanks for reading !
Source: https://www.linkedin.com/pulse/plan-pci-05-easy-steps-atoll-rachid-lamali/