eran3.0 pci conflict detection guide

Product Name Confidentiality level

DBS3900 LTE Internal

Product VersionTotal 47 pages

eRAN3.0

eRAN3.0 PCI Conflict Detection Guide

(For internal use only)

Prepared by LTE network I&V and maintenance department

Date2012-02-27

Reviewed by Date yyyy-mm-dd

Reviewed by Date yyyy-mm-dd

Granted by Date yyyy-mm-dd

Huawei Technologies Co., Ltd.

All rights reserved

eRAN3.0 PCI Conflict Detection GuideINTERNAL

Change History

Date Revision Version

Change Description Author

2011-03-18 1.0 Completed the M2000-based PCI conflict detection and self-optimization guide.

Jian Bin (Employee ID: 00163723)

2011-04-11 1.1 Added the description of U-Net-based PCI conflict detection.

Wang Yan (Employee ID: 00135165)

2011-04-20 1.2 Modified this document based on review comments from network technical support (NTS) personnel.

Wang Yan (Employee ID: 00135165)

2012-01-10 2.0 Adapted to eRAN3.0 by adding ANR-based PCI conflict detection and U-Net-based PCI optimization and added information to related contents.

Zhou Chao (Employee ID: 00138106)

2012-01-30 2.1 Modified this document based on online review comments.


2012-02-27 3.0 Modified this document based on review comments made by Ye Guojun.


4/21/2023-05-11 Huawei Confidential of 47


Contents

1 Overview..................................................................................................4

1.1 PCI and PCI Conflict.............................................................................................................................4

1.2 PCI Conflict Detection Methods for Commercial Use..........................................................................6

2 PCI Conflict Detection and Optimization by Using the M2000.........................8

2.1 License Check.......................................................................................................................................8

2.2 Scenarios for PCI Conflict Detection by Using the M2000..................................................................9

2.3 PCI Conflict Detection by Using the M2000......................................................................................11

2.3.1 Viewing PCI Conflict Information Contained in the PCI Optimization Task............................11

2.3.2 Viewing PCI Conflict Information by Checking the PCI Conflict Optimization Log...............13

2.4 PCI Self-Optimization by Using the M2000.......................................................................................14

3 PCI Conflict Detection by Using the U-Net.............................................20

3.1 Engineering Parameter Input to the U-Net..........................................................................................20

3.1.1 Formulating the Site Table.........................................................................................................20

3.1.2 Formulating the Sector Table.....................................................................................................21

3.1.3 Formulating the Cell Table.........................................................................................................21

3.2 Importing Site Information to the U-Net.............................................................................................21

3.3 PCI Query Method..............................................................................................................................33

3.4 PCI Conflict Detection Based on Geographic Information.................................................................38

3.4.1 PCI Conflict Detection Based on the Number of Reuse Tiers...................................................38

3.4.2 PCI Conflict Detection Based on the Distance..........................................................................41

3.5 PCI Optimization by Using the U-Net................................................................................................45



Key words: PCI Conflict Detection

Abstract: This document describes the background, principles, detection methods, and optimization

solutions of PCI conflict based on the M2000 and U-Net.

List of acronyms and abbreviations

Acronym or Abbreviation

Full Name

LTE Long Term Evolution

PCI Physical Cell Identity

eNodeB enhanced NodeB

UE User Equipment

ANR Automatic Neighbor Relation

NCL Neighbor Cell List

NRT Neighbor Relations Table



1 Overview

1.1 PCI and PCI Conflict

The physical cell identifier (PCI) in the Long-Term Evolution (LTE) is used to differentiate radio signals between cells. Each LTE cell corresponds to one PCI and the PCI determines whether signal synchronization and UE's access are successful, and also whether the handovers are successful. According to section 6.11 of 3GPP TS 36.211, there are 504 PCIs in total and the PCIs are classified into 168 PCI groups ranging from 0 to 167. Each group consists of three PCIs, ranging from PCIs 0 to 2.

If there are a great number of cells on the Evolved Universal Terrestrial Radio Access Network (E-UTRAN), one PCI may be used by several cells. In this case, if the PCI rule is inappropriate, PCIs are manually modified, or neighboring-cell parameters are modified, PCI conflict may occur and imposes great impact on the performance of the entire network. PCI conflict is divided into PCI collision and PCI confusion.

1. In PCI collision, two or more intra-frequency LTE cells with the same PCI are physically located with a short distance in between. As a result, the UE cannot properly perform synchronization in the overlap area between the two or more cells.

2. If the serving-cell Reference Signal Received Power (RSRP) and the measured-cell RSRP meet the handover threshold, the measured cell shares the frequency and PCI with the neighboring cell of the serving cell. As a result, handover failures and service drops may occur. This is known as PCI confusion. PCI confusion occurs in the following two scenarios:

Assuming that the measured cell (cell B) meeting the handover condition is the neighboring cell of the serving cell (cell A) and shares the frequency and PCI with another neighboring cell (cell C), the eNodeB cannot tell which neighboring cell is the measured cell, resulting in a handover failure.



Assuming that the cell B meeting the handover condition is not the neighboring cell of cell A but shares the frequency and PCI with cell C, the eNodeB mistakenly considers cell C as the measured cell and then initiates a handover to cell C. In this case, cell C (in PCI conflict with cell B) does not cover the current area, possibly resulting in a service drop.

1.2 PCI Conflict Detection Methods for Commercial Use

Currently, there are two PCI conflict detection methods for commercial use.

1. Use the M2000 to detect PCI conflict and perform PCI self-optimization. This mechanism is implemented based on the neighboring relationship.

2. Use the U-Net to detect PCI conflict. This mechanism is implemented based on the number of reuse tiers and the reuse distance. The two methods have different advantages and disadvantages, as described in the following table.

Tool Mechanism Based on

Characteristics

M2000 Neighboring Distributed and online



relationships Advantage: automatic detection and optimization, seldom requiring human intervention.

Note that the NE version is license-controlled. This mechanism is used by default in eRAN3.0.

U-Net Number of reuse tiers and reuse distance

Centralized and offline

Advantage: Independent of the NE structure; with geographical display of reused PCIs.

Disadvantage: Information tables to be imported to the U-Net need to be manually formulated based on engineering parameters of the eNodeB and detection conditions need to be configured.

Tool application scenarios:

You are advised to use the M2000 during the network optimization process, for example, at the time when NE configuration parameters including neighboring relationships change.

You are advised to use the U-Net after the network PCI allocation plan is completed, for example, at the time when eNodeB engineering parameters change and PCI information needs to be modified based on the network topology.



2 PCI Conflict Detection and

Optimization by Using the M2000

2.1 License Check

Before performing PCI conflict detection and self-optimization by using the M2000, run DSP LICENSE to query the license configuration.

The actual value in the red frame in the preceding figure is 1, indicating that the license in use supports PCI conflict detection and self-optimization.



2.2 Scenarios for PCI Conflict Detection by Using the M2000

M2000-based PCI conflict detection is automatically implemented. The PCI conflict detection is automatically triggered when eNodeB parameters including the frequency, PCI, neighboring cell list (NCL), and neighbor relation table (NRT) change. Changes of eNodeB parameters are caused by reasons including but not limited to:

1. The frequency, PCI, and neighboring-cell parameters (NRT or NCL) are manually modified.

2. The intra-RAT event ANR function adds neighboring cells and updates neighboring-cell PCIs after automatically detecting missing neighboring cells. For details, see Description of ANR Management Parameters.

3. The ANR-based active PCI conflict detection function adds neighboring cells and updates neighboring-cell PCIs.

4. The eNodeB updates the NCL after receiving the X2 Setup Request, X2 Setup Response, or X2 eNodeB configuration Update message.

The ANR function is switch-controlled and the online UE must support the ANR measurement and DRX function. If the ANR-supported UE is located in a handover area, missing neighboring cells can be easily added and PCI conflict is detected by using the ANR function.

The preceding reasons respectively trigger PCI conflict detection in the scenarios:

1. For reason 1, PCI conflict detection is triggered by changes of NE parameters.

2. For reasons 2 and 3, PCI conflict detection is triggered based on the ANR.

3. For reason 4, PCI conflict detection is triggered based on messages over the X2 interface.

5. The ANR switch is configured by running the following command:

MOD ENODEBALGOSWITCH: AnrSwitch=IntraRatEventAnrSwitch-

X&IntraRatFastAnrSwitch-X;

6. The UE supports the discontinuous reception (DRX) function.

3GPP TS 36.300 defines the missing-neighboring-cell detection function based on UE handover measurement. The UE can perform neighboring-cell measurement in the DRX dormancy period. For details, see Parameter Description for the DRX Feature. Therefore, a temporary DRX period for the UE to perform ANR measurement needs to be configured when the eNodeB perform ANR measurement. ANR measurement



information includes the E-UTRAN Cell Global Identifier (ECGI), tracing area code (TAC), and Public Land Mobile Network (PLMN) ID list.

The eNodeB automatically detects missing neighboring cells by using the intra-RAT event ANR function and checks whether PCIs of missing neighboring cells conflict with that of the serving cell. In eRAN3.0, the ANR-based PCI conflict detection function is newly added to check PCI confusion between configured and non-configured neighboring cells.

In ANR-based PCI conflict detection, transmitting and processing of measurement messages by the eNodeB occupy resources of the CPU and memory, consuming a lot of system resources.

To start the ANR-based PCI conflict detection, perform the following operations:

Step 1 Run the following command on the M2000.

MOD ANR: ActivePciConflictSwitch=X, StartTime=hh&mm&ss, StopTime=hh&mm&ss;

Table 2-1 Configuring parameters for the active PCI conflict detection

Parameter Name

Parameter ID Configuration Suggestions

Active PCI conflict detection switch

ActivePCI ConflictSwitch

To perform active PCI conflict detection, set the period of active PCI conflict detection (start time and stop time) and turn on this switch.

To disable or end active PCI conflict detection, turn off this switch.

Turn on this switch for cells with high service drop rate and low handover success rate (outgoing-handover success rate).

Start time of active PCI conflict detection

StartTime Indicates the start time of the active PCI conflict detection. The active PCI conflict detection is performed if the start time arrives and the active PCI conflict detection is turned on. You are advised to set the start time to be the period with many online users to increase the probability of detecting PCI conflict.

Stop time of active PCI conflict detection

StopTime Indicates the stop time of active PCI conflict detection.

The active PCI conflict detection is stopped if the stop time arrives and the active PCI conflict detection is turned on. The stop time is used along with the start time. The active PCI conflict detection is performed in the period with many online users.



2.3 PCI Conflict Detection by Using the M2000

There are three methods to detect PCI conflict.

Method 1: Turn on the PCI conflict alarm switch (by running MOD ENODEBALGOSWITCH: PciConflictAlmSwitch=ON;). You can view ALM-29247 Cell PCI Conflict on the alarm console. The alarm handling suggestions are contained in the AlarmEvent.chm file, which is released along with the version).

PCI conflict information can be viewed on the PCI self-optimization module of the M2000, regardless of whether or not the PCI conflict alarm switch is turned on.

Method 2: View PCI conflict information of the PCI optimization task.

Method 3: View PCI conflict information by checking the PCI conflict optimization log.

The preceding three methods are used to view PCI conflict detection information. Compared with method 1, Method 2 is straight in query and simple in PCI self-optimization.

Method 2 and method 3 are recommended and described in details.

2.3.1 Viewing PCI Conflict Information Contained in the PCI

Optimization Task

On the M2000 client, choose Configuration > LTE Self Optimization.



On the LTE Self Optimization tab page, click Optimization. In the Optimization navigation tree, choose PCI Optimization Task. In the displayed PCI Optimization Task window, click . If a cell has a neighboring cell having the same PCI, the cell is displayed in the PCI Conflict Information area.

As shown in the preceding figure, the cell with the GCI being 460-00-989-61 is configured with a neighboring cell using the same PCI. 460-00-989-61 indicates that Mobile Country Code (MCC) is 460, Mobile Network Code (MNC) is 00, eNodeB ID is 989, and cell ID is 61. The cell name of the cell is configured as cell 0, the NE name is RNO_HO_61, the frequency is 38750, and the conflicted PCI is 63.

Click the PCI conflict entry to view the neighboring cell in PCI conflict in the PCI Conflict Neighboring Cell area on the right.

As shown in the preceding figure, there are two neighboring cells using the same PCI with the serving cell. The GCIs of the two neighboring cells are 460-00-990-62 and 460-00-991-63, respectively. In addition, the cell name and NE name of the two neighboring cells are displayed. The GCI, cell name, and NE name are identified in the same way as above.



The PCIs of the two neighboring cells of the serving cell "RNO_HO_61" are verified to be 63 by running LST EUTRANEXTERNALCELL.

In addition, the two cells serve as intra-frequency neighboring cells of the same cell. Intra-frequency neighboring cells can be queried by running LST EUTRANINTRAFREQNCELL.

2.3.2 Viewing PCI Conflict Information by Checking the PCI

Conflict Optimization Log

View PCI conflict information by checking the PCI conflict optimization log.



2.4 PCI Self-Optimization by Using the M2000

PCI conflict detected in section 2.3 "PCI Conflict Detection by Using the M2000" can be automatically rectified by using the self-optimization function of the M2000.

In the PCI Optimization Task area of the LTE Self Optimization window, click in the Optimization Task area. The Launch Optimization dialog box is displayed. In the Launch Optimization dialog box, retain default values and then click OK.

Generally, the progress increases from 0% once an optimization task starts. When Success is displayed in t he Status field, the progress becomes 100%.

Alternatively, on the Setting tab page, double-click PCI Optimization Strategy. In

the displayed PCI Optimization Strategy window, click to create a PCI self-optimization analysis strategy. In this way, after an optimization task is started, you can select the preconfigured strategy name from the drop-down menu of the Strategy field and do not need to configure the start mode and delivery mode of PCI self-optimization. PCI self-optimization can be started in immediate or daily scheduled mode. PCI self-optimization results can be manually delivered, periodically delivered, or immediately delivered.



Parameters in the New Strategy dialog box are described as follows:

Parameter Name Configuration Suggestions

Optimization Analysis Mode > Immediate

If Optimization Analysis Mode is set to Immediate, the PCI self-optimization analysis immediately starts.

If PCI conflict needs to be immediately solved, set Optimization Analysis Mode to Immediate.



Parameter Name Configuration Suggestions

Optimization Analysis Mode > Daily Scheduled

If Optimization Analysis Mode is set to Daily Scheduled, the PCI self-optimization analysis starts at the fixed time in a day.

The time is set in hour-minute-second format.

If PCI self-optimization needs to be periodically performed, set Optimization Analysis Mode to Daily Scheduled.

The interval between the PCI self-optimization analysis and the PCI delivery cannot be excessively long to ensure that the PCI delivery result is calculated based on the latest collision information.

Optimization Implementation Mode > Manual

If Optimization Implementation Mode is set to Manual, the PCI self-optimization result needs to be manually delivered.

If the PCI self-optimization result needs to be verified, set Optimization Implementation Mode to Manual.


Optimization Implementation Mode > Immediate

If Optimization Implementation Mode is set to Immediate, the PCI self-optimization result is immediately delivered after the PCI self-optimization analysis is complete.

If the PCI self-optimization result needs to be immediately delivered after the PCI self-optimization analysis is complete, set Optimization Implementation Mode to Immediate.

Optimization Implementation Mode -> Daily Scheduled

>If Optimization Implementation Mode is set to Daily Scheduled, the latest PCI self-optimization result is delivered at the fixed time in a day.

The time is set in hour-minute-second format.

The period must be different for Optimization Implementation Mode and Optimization Analysis Mode, preventing the PCI self-optimization result from delivering during the optimization analysis process.

The PCI self-optimization result is recommended for delivery in idle hours.




Click in the PCI Conflict Information area. Two additional fields are displayed in the PCI Conflict Neighboring Cell area, as shown in the red frame in the following figure. The Recommended PCI field displays the PCI self-optimization result on the M2000.

As shown in the preceding figure, the M2000 determines to modify the PCI of the cell with the GCI being 460-00-990-62 from 63 to 0 and retains that of the other cell with the GCI being GCI being 460-00-990-63.

The following describes how to optimize conflicted PCIs in automatic mode. In the Optimization Advice area under the PCI Optimization Task area, view the recommended scheme for PCI modification (contents of the scheme are the same as

above). If recommended operations are confirmed, click . In the displayed dialog box, click Yes.



View the Status and Progress fields in the Optimization Task area until the task is complete.

After the progress reaches 100%, click in the PCI Conflict Information area. No PCI conflict information is displayed.

View serving cell information and corresponding neighboring cell information by running MML commands and observe that the PCI of the PCI-conflicted neighboring cell has been changed to the recommended value.

Run LST CELL to view the PCI configured for the serving cell.



Run LST EUTRANEXTERNALCELL to view the PCI configured for the neighboring cell.

The preceding figure shows that the PCI of the neighboring cell remains 63.

The PCI conflict detection and self-optimization are complete.

The PCI assigned in the PCI self-optimization analysis must be delivered to the NE before the PCI takes effect.

The cell must be blocked and then unblocked when the PCI is modified. The optimization suggestion is recommended for delivery in idle hours.


The PCI self-optimization result must not be delivered before the PCI self-optimization task is completed.



3 PCI Conflict Detection by Using the U-

Net

Obtain the U-Net at http://support.huawei.com/support/.

PCI conflict detection by using the U-Net is implemented based on geographic information. Assume that cell A is the serving cell, cells with the same PCI within X tiers or in a distance of Y meters are considered as PCI conflict cells. X and Y are thresholds that can be configured. For details about the tier and distance, see section 3.4 "PCI Conflict Detection Based on Geographic Information."

Field engineering parameters are entered for PCI conflict detection by using the U-Net. This document uses an LTE site as an example to describe the method of PCI conflict detection by using the U-Net.

3.1 Engineering Parameter Input to the U-Net

For details about the engineering parameter table, see LTE Engineering Parameters.xls of sites A, B, and C.

Formulate the Site Table, Sector Table, and Cell Table based on the engineering parameter table and import the three tables to the U-Net.

3.1.1 Formulating the Site Table

Mandatory fields in the Site Table include Site Name, Longitude, and Latitude. Obtain the site name, longitude, and latitude information from the engineering parameter table and formulate the Site Table.


http://support.huawei.com/support/


Pay attention that the engineering parameter table is provided based on a single cell. You need to combine all cell information of an eNodeB when formulating the Site Table. Site Name in the Site Table corresponds to SiteID in the engineering parameter table.

For details about the format, see 01 site.xls.

3.1.2 Formulating the Sector Table

Mandatory fields in the Sector Table include Site Name, Transceiver Name and Azimuth. Obtain the site name, transceiver name, azimuth information from the engineering parameter table and formulate the Sector Table. Site Name and Transceiver Name in the Site Table correspond to SiteID and CellName in the engineering parameter table, respectively.

For details about the format, see 02 transceiver.xls.

3.1.3 Formulating the Cell Table

Mandatory fields in the Cell Table include Transceiver Name, Cell Name, and PCI. Obtain the transceiver name, cell name, and PCI information from the engineering parameter table and formulate the Cell Table. Transceiver Name and Cell Name in the Site Table correspond to CellName in the engineering parameter table, respectively.

For details about the format, see 03 cell.xls.

3.2 Importing Site Information to the U-Net

To import site information to the U-Net, perform the following operations:

Step 1 Open the U-Net and then create a project.



Figure 3-1 U-Net interface

Choose File > New. In the displayed Project Templates dialog box, select LTE-FDD and click OK.



Figure 3-2 Interface showing a successfully-created project

Step 2 Establish a coordinate system.

Click the GEO icon to display the GEO tab page. On the GEO tab page, right-click Map in the navigation tree and choose Coordinate from the shortcut menu. In the displayed Coordinate Systems dialog box, select WGS84 UTM zones from the drop-down menu in the Find in field.



Determine a coordinate system in the following methods:

1. Analyze engineering parameters to judge whether the site belongs to the southern hemisphere or northern hemisphere. Positive latitude indicates the northern hemisphere and negative latitude indicates the southern hemisphere. For example, the latitude between 59 to 64 degrees is on the northern hemisphere.

2. Analyze engineering parameters to judge whether the site belongs to the east longitude or west longitude. A positive longitude indicates the east longitude and a negative longitude indicates the west longitude. For example, the longitude between 10 to 12 degrees is on the east longitude.

3. According to the longitude range, determine the specific coordinate system. For example, select a coordinate system based on 6 to 12 degrees of the east longitude on the northern hemisphere and then click Apply.



Step 3 Import site information.

In the Project Explorer window, click the network icon to display the network tab page. On the network tab page, right-click Site in the navigation tree and choose Import from the shortcut menu to import the Site Table.

Select a site table file.



Click Import in the Data Import dialog box.



In the Project Explorer window, click the network icon to display the network tab page. On the network tab page, select Site and right-click an eNodeB and choose Center in The Map from the shortcut menu.

The following map is displayed after the Site Table is successfully imported.

Step 4 Import sector information.



In the Project Explorer window, click the network icon to display the network tab page. On the network tab page, right-click Transceiver in the navigation tree and choose Import from the shortcut menu to import the Sector Table.

Select a transceiver file.




The following map is displayed after the Sector Table is successfully imported.



Step 5 Import cell information.

In the Project Explorer window, click the network icon to display the network tab page. On the network tab page, right-click Transceiver in the navigation tree and choose Cells > Import from the shortcut menu to import the Cell Table.



Select a cell file.



The following map is displayed after the Cell Table is successfully imported.

3.3 PCI Query Method

To query the PCI, perform the following operations:

Step 1 In the Project Explorer window, click the operation icon to display the operation tab page. On the operation tab page, right-click LTE PCI Planning in the navigation tree and choose Open PCI Codes from the shortcut menu.



The following figure shows the PCI Planning Display window. In the PCI Planning Display window, Cell Name indicates the cell name and Existing Code indicates the PCI of the cell. This figure shows PCI information of all cells on the network.



Step 2 Display PCI information on the map.

In the Project Explorer window, click the network icon to display the network tab page. On the network tab page, right-click Transceiver in the navigation tree and choose Display Setting from the shortcut menu.

In the displayed Display Field dialog box, select PCI in the Label Field area and then click Apply.



The following figure shows the corresponding PCI information.

Step 3 Display PCI information on the map.



In the Project Explorer window, click the operation icon to display the operation tab page. On the operation tab page, right-click LTE PCI Planning in the navigation tree and choose Display Option from the shortcut menu.

In the PCI Display Options dialog box, select Same PCI to display cells with the same PCI.

Click a cell on the map to display neighboring cells using the same PCI on the entire network in red lines. As shown in the following figure, after cell 2 of OSL060 with the



PCI being 37 is selected, the software associates to the other two cells with the PCI being 37, cell 2 of OSL236 and cell 2 of OSL201.

3.4 PCI Conflict Detection Based on Geographic Information

The U-Net checks PCI conflict based on geographic information in two ways: based on the number of reuse tiers and based on the distance. The following sections describe the two PCI conflict detection methods.

3.4.1 PCI Conflict Detection Based on the Number of Reuse

Tiers

To perform PCI conflict detection based on the number of reuse tiers, perform the following operations:

Step 1 In the PCI Planning Display window, right-click an entry and choose Filter from the shortcut menu.



Step 2 In the displayed Filter dialog box, select Reuse Tier (set to None by default) and set its value to 5 (the default value is 0; this value can be modified), and then click OK.

Definition of the number of reuse tiers

If the distance from eNodeB A to eNodeB B is used as the diameter of a circle, the number of eNodeBs in the circle is the number of reuse tiers between the two eNodeBs.

Reuse Tier is recommended to be 2. Theoretically, a larger value of reuse tier reduces the probability of interference. Generally, intra-frequency neighboring cells within two reuse tiers cannot use the same PCI for the purpose of avoiding PCI confusion (which may lead to handover failures).



Step 3 In the PCI Planning Display window, sort cell information. The following figure shows that there are three pairs of cells in PCI conflict within five reuse tiers.

Information in the preceding figure is displayed on a map as follows:

Cells not within configured reuse tiers are exported to an Excel file with specific information of corresponding codes, PCI conflict cells within the reuse tiers, and number of tiers.



3.4.2 PCI Conflict Detection Based on the Distance

If two cells have a long distance in between, signals of the two cells are largely isolated. If two cells have a short distance in between, signals of the two cells are slightly isolated, vulnerable to signal overlapping or interference. To ensure normal signal synchronization and successful access of UEs, cells closely located must have different PCIs.

In co-site scenarios where the evolved universal territorial radio access network (E-UTRAN) and the Wideband Code Division Multiple Access (WCDMA) network or GSM EDGE radio access network (GERAN) are deployed in the same site, the WCDMA scrambling reuse distance can be used as the LTE PCI reuse distance. If the distance between two cells using the same PCI is smaller than the PCI reuse distance, the two cells may encounter PCI conflict.

The WCDMA scrambling reuse distance is calculated based on the following formula:

Where, D indicates the shortest reuse distance.

R indicates the minimum cell radius and can be calculated by multiplying the average cell radius with 70% of the estimated minimum radius.

K indicates the number of scrambling codes of the serving cell corresponding to the interference neighboring cell and can be set to {1, 3, 4, 7, 9, 12…}. That is, if the primary scrambling code of the serving cell is different from that of the neighboring cell, a maximum of K codes is sufficient.

where, i and j indicate the number of cells within the scrambling reuse distance in different directions. For example, if seven primary scrambling codes are used and values of the i and j parameters are 2 and 1, respectively, the cell using the same primary scrambling code with the serving cell is located within a range that is two cells away from the serving cell in the southern or other direction and one cell away from the serving cell in the counter-clockwise 60-degrees direction.



Cells in a high-rise site

Reuse distance in urban areas: 10 km

Reuse distance in suburban areas: 15 km

Reuse distance in rural areas: 20 km

Common cell

In urban areas: 4 km

In rural and suburban areas: 12 km

To perform PCI conflict detection based on the distance, perform the following operations:

Step 1 In the PCI Planning Display window, right-click an entry and choose Filter from the shortcut menu.

Step 2 In the displayed Filter dialog box, select Reuse Distance (km) (set to None by default) and set its value to 3, and then click OK.



Step 3 In the PCI Planning Display window, sort cell information. The following figure shows PCI conflict cells within 3 km.



For example, cell 2 of OSL123 and cell 2 of OSL137 all use the PCI of 4 and have a distance of 2.675 km in between.



Cells not within the configured reuse tiers are exported to an Excel file with specific information of corresponding PCIs, LTE cell closest to the serving cell within the reuse distance range, and in-between distance.

The U-Net provides PCI conflict detection based on the number of reuse tiers and that based on the distance, which can be used by field personnel.

3.5 PCI Optimization by Using the U-Net

After obtaining PCI conflict cells, use the U-Net to replan PCI conflict cells and set PCIs properly.



To perform PCI optimization by using the U-Net, perform the following operations:

Step 1 Import the Site Table, Sector Table, Cell Table, and neighboring relationships.

Step 2 Manually clear conflicted PCIs in the Cell Table on the U-Net.

Step 3 Start the PCI optimization on the U-Net and set control parameters to With Exist PCI and With Neighbor to have the U-Net automatically reassign PCIs for PCI-conflicted cells (with PCIs cleared).

Step 4 Deliver replanned PCIs by using the Web LMT, M2000, or CME.

If With Exist PCI is selected, the U-Net plans PCIs only for cells with PCIs cleared. If the PCI of a cell has a value, retain the value.

You can clear PCIs of PCI-conflicted cells from the engineering parameter table before importing the Cell Table to the U-Net, or clear PCIs of PCI-conflicted cells from the Cell Table after importing engineering parameters to the U-Net.



The format of the neighboring relationship table is as follows:

From Network Planning

From Network Planning

CellName(*) NeighborCellName(*)

　　

　　

　　

Deliver replanned PCIs by using the Web LMT, M2000, or CME.


eran3.0 pci conflict detection guide

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