Neighbor Management Tool Overview

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Neighbor and Cell Parameter Management Tool Overview
2006-01-31

Introduction
Good neighbor and cell parameter management is crucial for the network quality of any cellular network. With the introduction of CDMA technology in the 3G networks, neighbor management becomes even more crucial. Missing neighbor definitions no longer means the risk of dropping the current call, but will introduce massive interference to other connections as well, resulting in decreased quality and/or lost connections for multiple users. At the same time network rollout speed is faster than ever before, with tens of sites being put on air every week, each being rescheduled for lack of building permissions, delays in electricity or transmission. Site integration order is subject to constant change, meaning need for re-planning of neighbor relations is constant. With the size of the current network rollout, responsibilities are split over a multitude of different people. While this probably is good for the rollout speed, it is disastrous for neighbor planning, since this easily falls between chairs. As if this was not enough, 3G networks are built by consortiums in different forms. This means neighbor relations must be managed not only within one 3G network, but also between partner networks, and even to roaming partners 2G networks. To facilitate management of neighbor relations, Canaima introduces it’s neighbor and cell parameter management concept.

Key Benefits
an automatic algorithm that produces useful neighbor relations which does not need immediate manual corrections and additions o based on signal strength predictions o unlimited area size o unlimited number of sites Prioritization of neighbor relations Deletion redundant neighbors Compares generated neighbors with actual, deletes redundant Automatic operation on scheduled basis User GGUI (GeoGraphic User Interface) for visualization and manual edits Scrambling code conflict visualization Scrambling code planner Interfaces to popular radio planning tools, such as Planet, Aircom Asset, Nokia NetAct and Ericsson EET Proven NMC interfaces via XML files (Nokia NetAct, Ericsson RANOS) Text file interface for bulk manual updates or interface to other system Full change history in database, i.e. who did what change when High performance multi-user database (SQL server or Oracle) 1 (18)

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NMT Overview 2006-01-31

System Overview
Radio Planning Tool NMT Service NMC Cellular Network

GIS

Database

The Neighbor Management Tool consist of two applications; a client program installed on each radio planners pc where neighbor relations are visualized and manually edited, and a server program on a central server where scheduled calculations and import / exports are handled. The server program can be installed on the central database server, or on a standalone machine in high performance configurations

Scheduled Imports, Calculations and Exports
Network change is constant, especially during intensive roll-out phases. New sites means new neighbor definitions needs to be added, and old ones removed. The system can be set up for daily synchronization with the radio planning tool and NMC to update the site database, coverage information and automatically recalculate neighbor definitions.

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12 Calc
Import Site Data Rehosting Site Integra tion Import NW dump Manual Edits Import Predict ions Neighb ors Import NW dump

On-site Edits in NW

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Manual Edits

3

Import NW dump Manual Edits Export Delta Import NW dump Manual Edits

6 Other jobs can also be scheduled such as regular import and export of data from other sources, automatic reports sent to subscribers by e-mail, consistency checks, e-mail logging. In the picture above a fresh NMC dump is imported into NMT in the morning. When the radioplanners arrive at work they can examine what the network looks like and manually add or delete neighbors. NMT also shows the suggested new neighbors calculated during the night. A radioplanner might be on the road measuring cells and neighbors and directly make some changes in the network on-site. These changes will appear in NMT after a new NMC dump is imported shortly after. Late in the afternoon all manual and automatic edits are loaded into the network by exporting a delta between the current state of the planned network and a fresh import of a NMC dump. Consistency checks are run to validate the data before exporting.

Full history database
NMT maintain its own database (in SQL Server or Oracle) of rnc, rbs, site, cell and neighbor data. The database provides complete history information, so the network can be tracked at any point in time, and latest changes can be tracked to user and time. NMT Overview 2006-01-31 3 (18)

Planned and Actual network
A live (or actual) network is continuously being changed. All changes are mostly planned in advance. A planned network is used which prepares and illustrates what the network will look like in a near future. The database contains both the planned and actual network, and can highlight any differences. The planned network contains data from the planning tool, automatic and manual neighbor creations, while the actual network is imported from NMC XML dump files.

PLANNED NETWORK

ACTUAL NETWORK

FUTURE IMPLEMENTATION

FUTURE REMOVAL CHANGES ALREADY IMPLEMENTED

Automatic Delta Generation
The changes in the planned network can be implemented in the actual network automatically. The latest image of the actual network is compared with the planned network. A delta is produced containing the differences (addition, deletion, update).

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PLANNED NETW0RK

ACTUAL NETW0RK

DELTA

The delta is stored in the database and can be exported to XML files. The export files are sent to the actual network either manually or automatically using e.g. FTP.

Regular Images of the Actual Network
Scheduled jobs can be defined in NMT which regularly fetch XML files from RANOS, OSS-RC or NetAct and imports an image of what the actual network looks like. The files can also be fetched from an FTP server using secure FTP. FTP XML DUMP FILE NMT scheduled imports

External OMCs
It is possible to import a live image from an external network. This is done by defining a system area for the external actual network and importing network dumps

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into this area. The actual import is done in the same way as the actual area is updated from an Ericsson 3GPP or Nokia RAML file.

Normal NW Dump

NMT NW Dump from external OMC

Network Areas
In NMT network changes are done using areas. There are two reserved system areas called PLANNED and ACTUAL. The actual area shows what the actual network looks like at a certain time. The actual area is built from a network dump from the NMC which is imported into NMT. The network dump is an XML file generated by RANOS, OSS-RC or NetAct. The planned area shows what the network will look like in a near future. All approved planned changes are stored in the planned area.

PLANNED

AREA

ACTUAL AREA

INHERITANCE

INHERITANCE

PHASE 2 PLANNED SUBAREA

REHOSTING SUBAREA

TEST SUBAREA

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A system area cannot be edited directly. Instead a subarea is created which inherits from the system area or from another area which already inherits from a system area. Subareas are often used to prepare future changes in the network. When the changes in the subarea have been verified and approved they are committed into its parent area which contains the planned network. Before commit is completed consistency checks can be run to validate the subarea. Example: A new site has been created and neighbors must be defined. A subarea is created which inherits from the planned area. All incoming and outgoing neighbor relations for the site are created. A number of consistency checks are run before the changes are committed into the parent area (planned). Some of the checks ensure that there are no scrambling code conflicts. The subarea is committed and the planned network is updated with the new neighbors. It is also possible to create a subarea to the actual network (area) and make some quick parameter changes which are later sent to the NMC for implementation. Example: A radio planner wants to test a new parameter configuration for a certain cell. The radio planner creates a subarea which inherits from the actual area. All parameter values are changed in the subarea for the specific cell according to the new parameter configuration. In order to load the changes into the live network the changed subarea is exported and saved as a 3GPP file which is imported into OSSRC.

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Workflow
1. Sites are defined in a radio planning tool 2. NMT imports site data from the radio planning tool automatically 3. (optional) NMT calculates neighbors automatically 4. Neighbors are edited manually in a Geographical User Interface 5. Radio parameters are configured manually and/or automatically 6. NMT imports NMC XML dump files automatically 7. NMT generates a delta between planned and actual network automatically 8. NMT runs consistency checks automatically 9. NMT exports delta files to the NMC automatically 10. NMT imports NMC XML dump files automatically 11. The implemented changes can be examined in a Geographical User Interface

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Geographical User Interface
NMTGIS provides a single geographical interface to radio planning data, cell configuration data, neighbor definitions and networks statistics, which makes up a very comprehensive tool for network planning, optimization and troubleshooting. The geographical user interface allows neighbor definitions and cell parameters to be geographically visualized on the map and manually edited.

Neighbor visualization and editing

Neighbors can be visualized by color coding sector symbols or circle representing cell, line connecting source and target cells or by color coding service area of source and neighbor cells.

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Cell Parameter visualization and edits
NMT can be used to visualize any cell, sector, site, rbs or rnc parameter. All cell parameters can be edited directly in the cell data grid.

Scrambling Code Planning
NMT provides functionality to identify scrambling code conflicts caused by cells having multiple neighbors with the same scrambling code. It also provides a tool to suggest SC:s based on reuse distances. SC conflict detection works also between 2G and 3G, i.e. 2G cells having multiple 3G neighbors with the same SC.

Filtering of visible cells
“Active” cells can be filtered and sorted on any cell parameter, for example show only cells with primaryCpichPower = 290. “Active” cells can also be filtered on any combination of System, Band, Milestones and site flags read from the radio planning system.

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Cell data history
Full history of cell parameter changes is maintained and accessible by clicking the ‘+’ sign in the cell data grid.

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Network Statistics
NMTGIS incorporates a very flexible query module that allows cells and neighbor relations to be associated with data from virtually any database. Typically this would be used to display and analyze network performance statistics, but can also be used to “plug” in data from network planning tools, rollout tools, equipment inventory database, alarm handling system, problem ticketing systems or even NMT’s own database.

Cell Statistics

Neighbor statistics NMT Overview 2006-01-31 12 (18)

Missing neighbor analysis
Many manufacturers of 3G mobiles lets the mobile report also undefined neighbors. These “Missing Neighbors” gets reported through test mobile tools such as TEMS or even as Events by the infrastructure (GPEH with Ericsson infrastructure). NMTGIS can read and present these events from both Ericsson GPEH files and TEMS export files.

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Raster maps and vector maps
NMTGIS supports ma data in both vector and rasterRaster maps with adjustable contrast for maximum readability.

High contrast map, good for orientation, bad for backdrop.

Low contrast map, perfect for backdrop.

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Color Schemes Editing
NMTGIS allows color schemes to be edited, globally or n a per user basis.

Other GIS functionality
NMTGIS allows some typical radio planning tool data, such as clutter, population density and coverage to be visualized. Unlike the typical radio planning tool, NMTGIS allows up to 6 layers of servers to be monitored by the follow-me mouse.

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Automatic Neighbor Calculation
The algorithm to produce neighbor relations works in four steps. 1. It will iterate through all “pixels” in the coverage predictions, and add neighbors between cells within a defined predicted signal difference. Priority is calculated based on a combination of signal difference and absolute signal. 2. It adds all co-site neighbors with highest priority 3. It adds all cells within a certain distance. Distance calculation is based on cell centre coordinates, not base station coordinates. This will ensure neighbor definitions for cells missing prediction files, or cells with service are too small (relative prediction pixel size) to have a valid service area in the coverage predictions. 4. Optionally it adds all mutual neighbors

Intra system (2G–2G or 3G–3G)
For each pixel in the coverage predictions, the algorithm works out and sorts the N strongest servers (N typically in the range 2 to 6). A signal threshold is applied in order not to generate neighbor definitions at predicted signal strengths lower than reasonable service thresholds. The signal difference (deltasignal) is compared between the strongest server and the N:th strongest (second strongest, third strongest etc). If the signal difference is lower than MaxDeltaSignal (value typically between 2 and 8 dB), a neighbor definition is added between the strongest cell and the N:th strongest cell, IN THE DIRECTION TO THE STRONGEST CELL. This means the algorithm generates one way neighbors. One way neighbors can be overruled if step 4, Force Mutual Neighbors, is enabled. Input data can be either raw radio predictions, or predicted array files. In the first case, the composites are automatically calculated by the tool, in the latter the composite coverage is read from the array files (requires the N best servers to be available in Array Files)

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Inter System (2G-3G, GSM900-GSM 1800)
The algorithms works out the N best servers for each system similarly to the intra system algorithm. Neighbor relations are generated between all inter system cell combinations where IntraSystemDeltaSignal <= MaxDeltaSignal difference and InterSystemDeltaSignal <= MaxInterSystemDeltaSignal. IntersystemDeltaSignal is the difference in predicted signal for each cell in respective system. MaxInterSystemDeltaSignal is typically a high value 20-60 db, and used to avoid neighbor definitions being generated in areas where one system is clearly dominating. It is possible to generate neighbors in one direction only (could be useful between operators for example). Input data can be either raw radio predictions, or predicted array files. In the first case, the composites are automatically calculated by the tool, in the latter the composite coverage is read from the array files (Inter system calculations works with N=1, meaning that a single best server array for each system can be used as input. For best results however, N should be in the range 2-4 for at least one of the systems)

Prioritisation
Early implementations of 3G networks have limitations to the number of neighbor relations they can handle. In case of 2G-3G handovers, or handovers between partnering networks, the number of desirable neighbor relations quickly increase to the maximum limit of what the system support. During Soft Handover in 3G networks, the neighbor list sent to the mobile is a compilation of the neighbor definitions of each of the source cells. Exactly how the compilation is put together is vendor specific, but at least in some instances the priority of each neighbor definition is used. All this raises a need for ranking of neighbor relations. The Canaima algorithm automatically calculates a ranking value, and prioritises the neighbors accordingly. Co-Site neighbors are always given the highest ranking value are ranked. Calculated neighbors are given a ranking value based on delta and absolute signal, resulting in cells with similar signal strength at high absolute power (small cells typically in city environment) will be given higher priority than larger delta signal and lower absolute signal strength (fringe coverage).

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System Requirement
The system runs on a PC platform using a workstation or server version of Windows and SQL Server.

Product Roadmap
Further development of the Neighbor Management Tool concept is planned. Feature Inter frequency handover algorithm Availability Spring 2006

Contacts and additional information
For additional information or to organize a demonstration, please contact: Per Wirdemark Canaima Communications AB +46 8 448 11 12 +46 70 348 39 56 [email protected]

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