4. PROJECT REPORT 4.1 To calculate calculate prediction prediction for overlapping zones After the coverage prediction of the sites, the next step is to calculate he prediction for the overlapping zones. We have checked the prediction by the coverage signal level, now we will check the prediction by the new parameter which is the “OVERLAPPING “OVERLAPPING ZONES”. ZONES”. The steps are are as follows:
Go to prediction->New
Select Overlapping zones->calculate
This the prediction of overlapping zones in atoll software:
OPTIMISATION PROCEDURE The optimization process starts immediately the network is brought into operational service or an enhancement takes place on the network. During times of little change to the network Performance Engineering monitor the quality of the network and will seek assistance from Optimization Engineers if the quality of the network begins to fall.
The following figure shows the PLANNED COVERAGE AND FIELD DATA
The procedure below is the basic method for Optimizing a system and can be modified to each operator to maximize results.
Before Optimization starts all of the pre-requisites must have been done or be in place. There must be a change control procedure in place with the operator that Motorola are familiar with, the RF design and Database parameters must be presented to the Optimisation control manager. All drive test teams must have test mobiles and SIM c ards provided by the operator. Note - The Optimisation control personnel are usually situated with the OMC personel for maximum effieciency as OMC and Optimisation control are continually passing information between each other.
The drive test routes must be agreed with the operator and a priority set on the routes for testing.
The drive test teams make test calls on the network of 2 minute duration with a 15 second break between calls to the MSC test number with the Test Mobile equipment (TEMS) and all data is
logged to the computer, location information is also taken using a GPS reciever to provide location information.
The drive test routes are usually 3 - 4 hours in duration so that the data collected can be managed.
During or after completion of the drive test r oute analysis of the data collected is done to find areas of dropped or noisy calls. This can either be done on the RF planning tool or using the GIMS software in the field
The results of the drive test, including analysis is passed to Optimisation Control for performance performance logging of the route.
Should the analysis of the route indicate problems of either dr opped or noisy calls , with the aid of the RF design and Database parameters an assesment is made to identify the possible source of interference causing the noisy or dropped call. If a call is dropped and no interference is present a retest is made in the same area, ar ea, if the scenario of the dropped call can be repeated, information of the problem cell should be obtained, this will then be escalated to Optimisation control to seek assistance from the BSS maintenance engineers to investigate the cell dropping calls.
Note - To assist in confirming possible sources of interference there may be a requirement to remove the suspected interfering channel. channel. This would be done via the optimisation optimisation control engineers . The suspected interfering carrier would be removed temporarily from service and test calls made again in the problem area, this would show if the interference had been removed. The process for temporarily removing carriers would have to be agreed with the operator, this usually varies as to the importance of the cell as to what time of day it can be taken out of service.
After conformation as to what is causing the problem with the drive test route, the drive test engineer will attempt to find a solution to the problem. This can be one of a number of possibilities i.e Power Change to BTS, Frequency Plan c hange, Neighbor addition required etc.
Note - In the case of a frequency plan problem, this is usually escalated through Optimisation Optimisation Control to the RF design engineer to find a solution to the problem. The RF designer and Optimiser for an area are usually the same engineer in Motorola, this has continually proven to be
the most efficient method of improving the quality of the network with respect to problems with the frequency plan of the network.
Once a possible solution to the problem has been found it may be possible in some circumstances to immediatly attempt the solution via the OMC, this usually relates to minor database changes and adding neighbors. The solution is implemented and proven immediately. If the problem is rectified the change remains in place and a change request is raised for the solution for the purpose of keeping records of all changes in the network. If the solution requires a major database change or antennae work a change request must be raised via the Optimisation Control Engineers. After the solution is implemented a retest of the problem area is carried out to confirm the problem has been solved.
In the event of the problem not being solved alternative solutions may be attempted, this process continues until it becomes immpossible immpossible to find a solution. At this point the problem is discussed with the operator as to the reasons that the problem cannot be solved for example the solution may require a new cell to be built, clearly this is beyond the scope of optimisation. If the operator is in agreement this particular problem will be removed from the drive tests until such time a solution is implemented.
Steps 3 to 10 are repeated throughout the system until such time that all routes meet the required metrics or no further improvement can be made due to circumstances outside the control of Motorola.
DRIVE TESTING It is a method method that is adopted adopted to optimized GSM network. Once a GSM GSM network is rolled out based based on network planning tool prediction. prediction. The nature of network hardly ressembles ressembles with the prediction so that the operator or the service provider tasks is to bring the network back as nearest as possible towards the prediction.
Through the systematic process of collecting the air interface data from the already built network status of existing network get recorded. The collected data is processed offline to know the deviation from the prediction as per the interpretation interpretation of thepre processing processing result configuration configuration changes changes are performed on the network. Then further DRIVE TEST is performed to check the modified status .after a few changes the network is brought very near to the prediction then the network is set to optimized
TYPES OF DRIVE TESTING 1)EXTENSIVEFOR SHORT CALLS 2)INTENSIVEFOR LONG CALLS
1)EXTENSIVE
FOR SHORT CALLS
The various parameters checked in this are like SSR , Handover Failure , Handover Success , FER , BER , RX Level .In this time is fixed of 60 sec for 100 calls.After 60 sec all the calls will be repeated.
2)INTENSIVE FOR LONG CALLS The various parameters checked in this are like C/A , C/I , BER , FER , ACCESS DELAY (which is time between channel request (RACH) And call alert (AGCH)).in this time is increased.After 120 sec all the calls will be repeated.
PERSONEL REQUIREMENTS The intention here is to show the engineers required in the optimisation process and not the amount of engineers. The amount of engineers will depend on the size of the network, the amount of area to be covered and the roll out schedule.
Once the above information is known a more precise proposal can be done detailing specific numbers of people required.
The engineers required in the optimiation process is as follows
Type of Engineer
Functions
OMC Engineers
Statistical feedback, Network availability, Database change
Drive Test Engineers
Drive Testing, Performance evaluation, Antennae and database Changes.
Performance Engineer
OMC Statistical Analysis, Quality Metric figures.
BSS Mtce Engineer
Fault Identification and Clearance
Antennae Riggers
Antennae Azimuth and downtilt changes
Optimisation Control
Management responsibilities responsibilities of all staff, Presentation of Quality Metrics, Technical Guidance to Engineers, Change control Management.
OPTIMISATION TOOLS AND SOFTWARE ATOLL The atoll version 2.8.0 is used for network planning and optimization. We can predict the coverage of planned site by atoll. OMC The OMC is an a n integral part of a GSM system, its relationship to the Optimisation process is to provide statistics for the quality metrics and information on the status of the network.
Tems Tems is the drive test mobile and software from Erisoft. The kit consists of a laptop P.C, an Ericsson GH688 test mobile and a GPS reciever for positioning information.
Mapinfo Mapinfo is a GIS software tool, it is used to display drive test data for analysis and to produce Optimisation reports in a clear and easy manner.
Test Mobiles Test mobiles are an invaluable source of information, all field engineers should be equipped with a test mobile to identify problem areas.The test mobile should be capable of giving the recieved signal level, RXQual value, Cell I.D and six neighbors with rxlevels.
CREATING AN ATOLL DOCUMENT Whatever the radio technology you will be modelling, you create an Atoll document in one of two ways:
• From A Document Template: You can create a new Atoll document from a template. Atoll is delivered with a template for each technology you will be planning for. You can also create your own template by basing it on an existing document that you have already customised with, for example, certain geo data or antennas.
• From An Existing Database: When you create a new Atoll document from a database, the database you connect to has been created cr eated with the technology and data you need. Working with a database allows several users to share the same data while at the same time managing data consistency. The exact procedure for creating a new Atoll document from a database differs, depending on the database containing the data. Atoll can work with several common databases.
Managing Geographic Data Several different geographic data types are used in an Atoll document. For example: the Digital Terrain Model (DTM), clutter classes, clutter heights, scanned images, population maps, and traffic data maps are types of the geographic data that you can import or create. Some data types, such as clutter classes, can be used to give more realistic calculations. Other types such as scanned images, ar e used to create a more realistic display of the region under study. You can import a wide variety of both vector and raster-format geo data files. When you import a geo data file into Atoll, Atoll, you can decide in which folder it goes. The Geo tab of the Atoll Explorer window has folders for the commonly used data types. Therefore, choosing a folder is choosing what the file will be used for. You can also create your own data type by importing a file and defining what data is to be used. Once you have imported a file into the Atoll document, you can edit the data, define how the geo data will be displayed. Atoll also allows you to manage multiple files for a single data type, deciding the priority of data files with different information or different resolutions. You can also display geo data over items on the Data tab, t ab, either by transferring them to the Data tab, or by importing them directly to the Data tab. .
Geographic Data Types An Atoll document can contain several different geographic data types. Atoll supports a wide range of file formats for geographic data files. The different geographic data types play different roles in the Atoll document:
• Geographic data used in propagation calculation: - Digital terrain model - Clutter classes - Clutter heights
• Geographic data used in dimensioning: - Traffic maps
•
Geographic data used in statistics:
- Population maps - Custom maps
Clutter Classes The clutter class geo data file describes land cover or land use. Each pixel of a clutter class file contains a code (from a maximum of 256 possible classes) which corresponds to a clutter class, or in other words to a certain type of ground use or cover. The height per class can be defined as part of the clutter class, however this height is only an average per class. A clutter height map can represent height much more accurately because it allows a different height to be assigned for each bin of the map.
Clutter Heights Clutter height maps describe the altitude of clutter over the DTM. Clutter height files allow for a higher degree of accuracy because they allow more than one height per clutter class. In a clutter height file, a height is given for each point on the map. If you define clutter height as a property of clutter classes, the height is given as an average per clutter class.
Managing Calculations in Atoll
Once you have created a network, you can make predictions. There are two types of predictions:
• Point predictions using the Point Analysis tool: The Point Analysis tool allows you to predict, at any point on the map, the profile between a reference transmitter and a receiver, the value of the signal levels of the surrounding transmitters, an active set analysis for UMTS, CDMA2000, and TD-SCDMA projects and an interference analysis for GSM/GPRS/EDGE projects.
• Coverage predictions: You can calculate standard coverage predictions, coverage by transmitter, coverage by signal level and overlapping zones, and specific coverage studies such as interference studies for GSM/GPRS/EDGE projects or handover, service availability, etc. for UMTS, CDMA2000 and TDSCDMA projects. Many customisation features on coverage studies are available in order to make their analysis easier. multithreading and distributed Atoll facilitates the calculation of coverage predictions with support for multithreading calculating. The progress of the calculations can be displayed either in the Event Viewer window or in a log file. Atoll also allows you to use polygonal zones to limit the amount of resources and time used for calculations. The polygonal zones, such as the filtering zone and the computation zone, help you to restrict calculations to a defined set of transmitters, and to limit calculations and coverage predictions. Depending on the type of project you are working on, you can choose between the propagation models available in Atoll
MAKING COVERAGE PREDICTIONS A coverage prediction displays the results of defined coverage conditions. It is calculated using the path loss matrices and is based on coverage conditions and coverage resolutions. After calculation, Atoll displays the results as a graphical representation of the pixels for which the defined coverage conditions are satisfied. Atoll offers the following general coverage predictions, available for all technologies:
• Coverage by transmitter • Coverage by signal level
• Coverage by overlapping zones. Atoll also offers technology-specific coverage predictions, described in the technology-specific chapters, for example:
• Interference Interference studies in GSM/GPRS/EDGE projects • Coding scheme and throughput studies for GPRS/EDGE • UMTS or CDMA2000 coverage predictions. Atoll gives you a large flexibility over how the results of your coverage prediction are displayed. You can select which attributes should be displayed on the map and how they are displayed. As well, you can define information to be displayed in the legend, in the label, or in tooltips. Furthermore, Atoll also allows you to filter, sort, or group results before displaying them.
Optimising and Verifying Network Capacity An important step in the process of cr eating a GSM/GPRS/EDGE network is verifying the capacity of the network. This is done using measurements of the strength of the pilot signal in different locations within the area covered by the network. This collection of measurements is called a test mobile data path. The data contained in a test mobile data path is used to verify the accuracy of current network parameters and to optimise the network.
FREQUENCY PLANNING USING ATOLL
MODEL TUNNING USING ATOLL
BIBLIOGRAPHY:1. 2. 3. 4. 5.
Daily diary www.atsol.co.in www.wikipedia.com www.radioelectronics.com MODULES
REFERENCES:1. www.atsol.co.in 2. www.wikipedia.com 3. www.radioelectronics.com 4. Daily Diary 5. Modules
