exemplary gsm-gprs planning with a9155 v64
DESCRIPTION
Gsm-gprs PlanningTRANSCRIPT
Alcatel 9155 RNP
Application Note
Exemplary GSM/GPRS Planning with A9155 V6.4
3DF 01955 6460 UAZZA Edition 01
Status RELEASED
Change Note
Short Title Exemplary GSM/GPRS Planning with A9155 V6
All rights reserved. Passing on and copying of this document, use and communication of its contents not permitted without written authorization from Alcatel
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Contents
Contents
.........................................................................1 Alcatel 9155 RNP
.......................................................................................3 Contents
.........................................................................................5 Figures
..........................................................................................5 Tables
................................................................6 Referenced Documents
...........................................................................................7 Scope
..........................................................................8 1 Introduction
............................................................................10 2 Geo Data
2.1 ......................................................10 Coordinate system2.2 ..........................................................................10 Maps
2.2.1 ................................................10 Topography2.2.2 ........................................................11 Clutter
2.3 .......................................................................13 Vectors2.4 .......................................................14 Building database
............................................................15 3 Traffic assumptions
3.1 ..............................................................15 Traffic density3.2 .................................................................16 Traffic map
....................................................17 4 Propagation parameters
..................................................................21 5 Network design
5.1 ...............................................................22 Site template5.2 ....................................................................23 Antennas5.3 ...........................................................24 Design strategy
5.3.1 ........................25 Neighbor allocation strategy5.3.2 ...........................................26 Frequency plan
................................................................32 6 Template studies
6.1 ...............................................32 Classification of studies
....................................................................35 7 Measurements
............................................40 8 Urban propagation modelling
8.1 ....................................................40 Propagation models8.2 .......................................................................41 Settings
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Contents
8.3 .....................................................43 Models comparison
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Figures
Figures
Figure 1: Topological database....................................................................11 Figure 2: Morphological database ...............................................................12 Figure 3: Vector database............................................................................13 Figure 4: Building database.........................................................................14 Figure 5: Traffic map...................................................................................16 Figure 6: General settings for the station template ........................................22 Figure 7: Transmitter settings for the station template ....................................23 Figure 8: GPRS settings for the station template ............................................23 Figure 9: Neighbor allocation algorithm settings - first step ...........................25 Figure 10: Neighbor allocation algorithm settings - second step ....................26 Figure 11: Neighbor allocation algorithm settings - third step........................26 Figure 12: Cell type properties .....................................................................27 Figure 13: Interference matrix calculation settings .........................................28 Figure 14: Algorithm control settings ............................................................29 Figure 15: Violation costs settings.................................................................30 Figure 16: Channel separation constraints....................................................31 Figure 17: CW measurements parameters....................................................36 Figure 18: CW measurements path..............................................................37 Figure 19: Measurement window displaying measurements (red) and
predictions (blue) ....................................................................38 Figure 20: Statistics window .........................................................................38 Figure 21: Database settings for WinProp.....................................................42
Tables
Table 1: Statistical distribution of the clutter class ..........................................12 Table 2: Traffic density ................................................................................15 Table 3: Propagation parameters.................................................................18 Table 4: "Clutter" tab of the SPM_900 propagation model .............................19 Table 5: Model standard deviation values.....................................................20 Table 6: Antenna pattern used by the station template ..................................24 Table 7: Frequency domains used for AFP run ..............................................27 Table 8: Exceptional pairs list.......................................................................31 Table 9: The list of template studies for GSM/GPRS projects ..........................33 Table 10: Propagation model comparison - SPM900, CWI............................43 Table 11: Propagation model comparison - 2D real, 3D IRT..........................44
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Referenced Documents
Referenced Documents
[1] A9155 User Manual V6.4 3DF 01955 6480 PCZZA
[2] A9155 V6 Default Parameter Set 3DF 01955 6042 DSZZA
[3] Study Templates for A9155 V6.4 3DF 01955 6420 PTZZA
[4] Propagation Model Calibration application note 3DF 01955 6081 BGZZA
[5] A9155 V6 RNP Application Note: Frequency planning 3 DF 01955 6082 BGZZA
[6] A9155 V6 WinProp-ProMan V5.81 User Manual 3DF 01955 6082 PCZZA
[7] A9155 V6 WinProp-WallMan V5.81 User Manual 3DF 01955 6083 PCZZA
[8] A9155 V6 WinProp-ProMan V5.81 Reference Manual 3DF 01955 6083 RKZZA
[9] A9155 V6 Application Note: Propagation Model Selection 3 DF 01902 0010 VAZZA
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Preface
Scope
Purpose of this document
The objective of this document is to get an overview of the exemplary GSM planning with the Alcatel network planning tool A9155 V6. It shows the planning procedure and parameters based on the A9155 V6 default parameters.
This document should be used with the planning file “GSM-GPRS_ExPlanA9155_v6.atl” for internal and external customers. It can be found on the A9155 V6 installation CD.
Area of application
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1 Introduction
1 Introduction
This is a GSM/GPRS planning with the Alcatel network planning tool A9155 V6. It shows the main steps to be performed with A9155 V6 when planning a GSM network. A GSM network in the area of Stuttgart will be designed step by step.
The main steps for creating a GSM project with A9155 V6.2 are the following:
• Choose a coordinate system fitting to the maps.
• Import maps for display and further calculations in the tool. Several geographical data types are supported within A9155: digital terrain model, clutter classes, clutter heights, vectors, scanned images, population maps, generic maps.
• Define a calculation zone on the map for the area of interest for the planning; this will reduce the calculation area and time for statistics, path loss calculation and predictions.
• Define station templates that will be used for the sites in the network or use the defined ones. A station template defines the main parameters of the transmitters: antenna type, downtilt, height, the cell type, propagation model, EIRP etc.
• Build the network by adding sites on the map based on the defined station templates.
• Define coverage predictions to analyse the created network in order to optimise it: adjust downtilt, power, azimuth, height. The goal is to have a good coverage for the populated areas on the map.
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1 Introduction
• Allocate the neighbours for the transmitters using the automatic allocation algorithm.
• Define the frequency bands and groups with the available frequencies for the operator and requested hopping types and assign the corresponding cell types to transmitters. Define the number of requested number of TRXs based on the estimations of the customer in case of a new network or calculate automatically based on traffic maps.
• Allocate the frequencies (and corresponding HSN and MAIO) to the transmitters based on the requested number of frequencies and the constraints in terms of available frequencies using the automatic frequency planning (AFP) module.
• Analyse the quality of the frequency plan by defining interference predictions. Eventually re-run the AFP with tuned parameters based on the results of the interference analysis. The goal is to have a good frequency plan in terms of using the available spectrum and causing a minimum interfered area in the network.
• Analogue or digital measurements from the real network can also be imported in A9155 for checking the quality of the network and calibrate the propagation model in order to have more reliable predictions for specific areas. Some sample measurements were imported in this exemplary project to illustrate this feature.
• If building databases are available, deterministic propagation models can be used to determine the coverage of the network in urban environment, using the Winprop module of A9155.
These steps had been followed in this exemplary GSM/GPRS project. In the following chapters the input data for and the results of those steps are described in more detail, together with the corresponding settings for this project.
For this project the following versions of the planning tool and corresponding modules were used:
• A9155 V6.4 B1453
• AlcAFP version 1.1.2.9
• Winprop version 5.81.
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2 Geo Data
2 Geo Data
This part presents the coordinate system and maps used in the planning.
2.1 Coordinate system
The used coordinate system for the Stuttgart area is UTM zone 32N based on the ellipsoid WGS 84. As all the imported geographic files are referenced in the same projection system, the projection and display systems are the same. In this area a computation zone was defined.
2.2 Maps
The predictions with Alcatel A9155 V6 are based on topographical, morphological and traffic databases. The resolution of the databases is 20m in x- and y-direction.
2.2.1 Topography The topographical database reflects the ground elevation. The digital terrain map is taken into account in computations by the propagation model.
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2 Geo Data
Figure 1: Topological database
2.2.2 Clutter The Clutter is the morphological database. It reflects the urbanization and land use of the area, where each pixel is allocated to a main type of clutter class.
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2 Geo Data
Figure 2: Morphological database
Name Surface (km²) Percentageskyscrapers 0.0296 0dense_urban 7.6976 1.9medium_urban 38.9452 9.7lower_urban 66.05 16.4residential 21.3792 5.3industrial_zone 8.6548 2.1forest 83.7616 20.8agriculture 84.2584 20.9low_tree_density 38.1612 9.5water 2.8976 0.7open_area 34.3268 8.5airport 0 0quasi_open 16.5296 4.1
Table 1: Statistical distribution of the clutter class
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2 Geo Data
2.3 Vectors
The available vector data represents the airstrip, water, railways, streets, main roads and highways. It is only used for display only and is not considered on computations.
Figure 3: Vector database
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2 Geo Data
2.4 Building database
The building databases can be used for calculations (see chapter 8) or as display layer, like the vector database. It is useful in correlation with the predictions done with the urban propagation models in order to see the predicted signal level along the streets and buildings. The predictions with the urban propagation models are detailed in chapter 8.
Figure 4: Building database
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3 Traffic assumptions
3 Traffic assumptions
3.1 Traffic density
The traffic map was created based on the clutter map.
Then density classes were assigned to each clutter class.
Traffic density Clutter class (Erlang/sqkm)
skyscrapers 14 dense_urban 14 medium_urban 12 lower_urban 8 residential 6 industrial_zone 7 forest 5 agriculture 2 low_tree_density 6 water 1 open_area 2 airport 10 quasi_open 0
Table 2: Traffic density
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3 Traffic assumptions
3.2 Traffic map
The used traffic map is shown in Figure 5. It shows the traffic density for each clutter class.
Figure 5: Traffic map
The traffic map was used in the project in order to dimension the transmitter network. Since the reference element for carrying data is TRXs, the dimensioning consists in determining the number of TRXs required for each transmitter in order to handle a certain amount of the defined circuit traffic. Based on this dimensioning, the automatic frequency planning module is allocating the frequencies.
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4 Propagation parameters
4 Propagation parameters
By computing losses along transmitter-receiver paths, propagation models permit to predict the received signal level at a given point.
The used propagation model is SPM_900 (Standard Propagation Model for 900).
The SPM_900 is a model particularly suitable for predictions over long distances (1 < d < 20km) and is adapted to GSM 900. This model uses the terrain profile, diffraction mechanisms and takes into account clutter classes and effective antenna heights in order to calculate path loss.
For default settings of the SPM parameters please refer to [2].
In this project the following settings were used:
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4 Propagation parameters
Near transmitter Max. distance 0 K1 – los 12.4 K2 – los 44.9 K1 – nlos 12.4 K2 – nlos 44.9 Far from transmitter K1 – los 12.4 K2 – los 44.9 K1 – nlos 12.4 K2 – nlos 44.9 Effective antenna height Method 1 – Height above
average profile Distance min (m) 200 Distance max (m) 2000 K3 5.83 Diffraction Method 1 – Deygout K4 1 Other Parameters K5 -6.55 K6 0 Kclutter 1 Hilly terrain correction 0 - No Limitation to Free Space Loss 1 - Yes Profiles 0 – Radial Grid calculation 0 – Centred
Table 3: Propagation parameters
Heights Use clutter Heights 1 - Yes Receiver on top of clutter 0 - No Range Max. distance 300 Weighting function 1 – Triangular Losses per clutter classes 1 – skyscrapers 0 2 – dense_urban -2 3 – medium_urban -4 4 – lower_urban -6 5 – residential -8 6 – industrial_zone -10
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4 Propagation parameters
7 – forest -8 8 – agriculture -20 9 – low_tree_density -15 10 – water -27 11 – open_area -27 12 – airport -27 13 – quasi_open -25 Clearance per clutter classes 1 – skyscrapers 10 2 – dense_urban 10 3 – medium_urban 10 4 – mean_urban 10 5 – lower_urban 10 6 – quasi_open 10 7 – residential 10 8 – village 10 9 – open 10 10 – agriculture 10 11 – low_tree_density 10 12 – forest 10 13 – water 10
Table 4: "Clutter" tab of the SPM_900 propagation model
The standard deviation values according to the different clutter classes used are as shown in the following table:
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4 Propagation parameters
Model standard deviation Clutter class
skyscrapers 6 dense_urban 6 medium_urban 7 lower_urban 7 residential 6 industrial_zone 10 forest 8 agriculture 6 low_tree_density 8 water 5 open_area 6 airport 0 quasi_open 0
Table 5: Model standard deviation values
OBS: The standard deviation values defined per clutter class are mandatory if the user wants to increase the reliability level of the predictions by considering shadowing margins for the predicted signal level.
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5 Network design
5 Network design
The network design comprises the settings for the transmitters, the used antennas and the design strategy in terms of neighbours and frequencies allocation.
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5 Network design
5.1 Site template
The transmitters in the network used a customized station template for GPRS, defined by the parameters below:
Figure 6: General settings for the station template
The template value for the EIRP of the transmitters was used only as an initial setting, it was further tuned for certain transmitters in
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5 Network design
order to optimize the coverage and the overlapping between the serving areas of the different serving cells.
Figure 7: Transmitter settings for the station template
Figure 8: GPRS settings for the station template
5.2 Antennas
The antenna used for the station template was 3BK311_20AB. The parameters are the following: Parameter Value Supplier Celwave Frequency range 900 MHz Gain 15 dBi H Beamwidth 65 degrees V Beamwidth 13 degrees Electrical downtilt 0 degrees Dual polarization ±45° Height 1300mm Width 306 mm
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5 Network design
Depth 120 mm
Name Horizontal pattern Vertical pattern
900_65_15_3BK311_20AB 0
10203040
010203040506070
Co-Polar Co-Polar
Table 6: Antenna pattern used by the station template
5.3 Design strategy
The network design is created with the following steps:
●
●
●
●
●
●
●
●
Setup of working zone.
Derive from a link budget tool for standard environments the cell ranges related to the given traffic density.
Place a few sites taking into account the cell radii derived from the link budget tool.
Perform coverage calculations.
Move, add and delete sites to complete the network design. The populated areas of the map should be covered with signal.
Automatically assign the neighbors.
Automatically assign frequencies.
Create interference studies to analyze the quality of the network. Optimize the frequency plan in order to minimize the interference in the network.
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5 Network design
The created network was not very optimized in some areas in order to allow later suggestive studies like for example interference predictions.
5.3.1 Neighbor allocation strategy The neighbors were allocated automatically using the neighbor allocation module of the tool. In order to have final good results of the neighbor relationships, an allocation in several steps was performed. The settings when allocating the neighbors were tuned for this specific network: maximum inter-site distance, %min covered area, number of neighbors.
The allocation process was done in 3 steps, with the following settings:
● First step: settings tuned for allocating the close transmitters as neighbors, as the network has areas with different density of the transmitters
Figure 9: Neighbor allocation algorithm settings - first step
● Second step: increasing the maximum inter-site distance and number of neighbors
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5 Network design
Figure 10: Neighbor allocation algorithm settings - second step
● Third step: forcing symmetry of the neighbor relationships together with increasing the distance and min covered area in order to avoid having too many additional neighbors that finally cause removal due to symmetry reasons.
Figure 11: Neighbor allocation algorithm settings - third step
5.3.2 Frequency plan The prerequisites for a frequency planning are mainly:
●
●
a coverage prediction (in order to calculate the predicted interference matrix)
a requested of number of TRXs (based in this case on a traffic map)
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5 Network design
● the neighbourhood relations in the network.
In the current document only the settings used for the frequency plan generation process will be detailed.
For more detailed information about the prerequisites for an automatic frequency plan in A9155 V6 and the allocation process please refer to [5].
The cell type used for the transmitters of the network is GSM900_N_NORMAL as defined bellow:
Figure 12: Cell type properties
The BCCH and TCH domains used for allocation were:
Domain Group Min Max Step
Domain_GSM900_BCCH Domain_GSM900_GroupBCCH 1 18 1 Domain_GSM900_TCH Domain_GSM900_GroupTCH 20 55 1
Table 7: Frequency domains used for AFP run
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5 Network design
The interference matrix was calculated with the following settings:
Figure 13: Interference matrix calculation settings
For the automatic frequency allocation was done with the following AFP settings:
• “Algorithm control” tab of the AFP Properties – the reason for setting “Keep only frozen frequencies” is because in the network also some real transmitters implemented in Stuttgart were integrated in order to integrate measurements and they were considered in the neighbour allocation and frequency plan, keeping their real frequencies to match the measurements.
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5 Network design
Figure 14: Algorithm control settings
The second screenshot is referring to the violation costs associated with the constraints imposed for the frequency plan allocation.
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5 Network design
Figure 15: Violation costs settings
The constraints imposed in terms of channel separations when running the AFP were the following:
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5 Network design
Figure 16: Channel separation constraints
Based on these constraints, the AFP module was run several times and the parameters were tuned in order to optimize the automatically allocated frequencies. As one of the tuning actions, a list of exceptional pairs was defined.
Transmitter1 Transmitter2 Separation TRX type TRX type2 Site20_0 Site26_1 2 TCH TCH Site20_1 Site0_1 2 BCCH BCCH Site26_1 Site5_3 2 TCH TCH Site26_1 Site25_0 2 TCH TCH
Table 8: Exceptional pairs list
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6 Template studies
6 Template studies
The Exemplary Planning project contains also a set of studies performed in different steps of the planning in order to analyse the quality of the planned network.
The studies are defined according to the set of template studies for planning using A9155 V6. In the following subchapter just a short presentation of the defined studies are included.
For further details concerning these templates please see [3].
6.1 Classification of studies
The set of template studies are grouped into different categories according to their purpose and recommended usage:
●
●
●
●
Coverage studies: studies that give an overview of the coverage in the network and cell specific signal levels (field strengths).
Miscellaneous studies: studies that give additional information besides the ones from the coverage studies category. They are optional during the analysis of the network, like for example the number of servers study and best second server study.
Interference studies: this kind of studies gives an overview of the overall C/I conditions in the network as well as the interfered areas for all, BCCH or TCH channels.
Visualization studies: complementary studies for the interference ones that allow an analysis of the frequency
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6 Template studies
spectrum allocation and the worst interferers, respectively interfered transmitters in the network.
●
● ● ● ● ●
EDGE/GPRS studies: these are studies specific to EDGE or GPRS-enabled transmitters.
According to these categories, the template predictions have an associated code at the beginning of the name together with a number that indicates the logical sequence of predictions that should be made for a certain network. This rule follows the common steps in the planning process:
setup of the sites and coverage analysis optional studies for the coverage analysis interference analysis after a frequency plan more specific studies for quality of the network analysis optional EDGE/GPRS studies in case of enabled cells in the network.
Category Name
C1: Signal level per cell Coverage studies
C2: Best signal level in network
C3: Best server at each pixel
C4: Coverage probability for best server
C5: Coverage probability per cell
M1: Second best server in network Miscellaneous studies
M2: Number of servers at each pixel
M3: Overlapping between the best servers
M4: Number of TRXs per cell
I1: Overall C/I level in network Interference studies
I2: Global interfered areas per cell
I3: Interfered areas for BCCH channel per cell
I4: Interfered areas for TCH channel per cell
V1: Frequency distribution in the network Visualization studies
V2: Worst interferers in the network
V3: Worst interfered transmitters in the network
G1: Best throughput/timeslot based on C EDGE/GPRS studies
G2: Best throughput/timeslot based on C/I
G3: Best coding scheme based on C
G4: Best coding scheme based on C/I Table 9: The list of template studies for GSM/GPRS projects
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6 Template studies
For further details on the GPRS topic you can refer to:
[10] for GPRS basic, procedures, restrictions and recommendations for Alcatel GPRS parameters and features;
[11] for GPRS radio network engineering relevant aspects and RNP engineering guideline.
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7 Measurements
7 Measurements
For detailed information about managing measurement data please refer to [1].
In A9155, the measurement module provides two types of drive tests: CW measurements and Test mobile data.
The aim of CW measurements is to analyze measurements made on the real field referring to only one transmitter in order to calibrate propagation models. The calibration of the propagation models is done in order to improve the reliability of the predictions.
Test mobile data refer to measurements related to several servers, each point referring to a serving cell and to a list of neighbors. The goal of test mobile data is to check and to improve the quality of an existing network.
In this project some CW measurements were imported as an example of the A9155 capabilities to manage such data, and not to prove the calibration process. In a calibration process a bigger set of measurements are requested. For detailed information describing all the steps and analysis of the calibration process please refer to [4].
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7 Measurements
The settings of the imported measurements are the following:
Figure 17: CW measurements parameters
The overall measurements path is the following:
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7 Measurements
Figure 18: CW measurements path
In A9155, is possible to make coverage predictions along a CW measurement path, using the reference transmitter for the current CW measurement session. This feature is possible using any prediction model along an existing CW measurement path.
In this project a comparison between the SPM_900 propagation model and the measurements was done, in order to analyse the accuracy of the predicted values. This is one of the initial steps in the decision and process of calibrating a propagation model.
The comparison can be done using the measurements window together with the statistics window that gives a summary on the difference between the predicted and the measured values.
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7 Measurements
Figure 19: Measurement window displaying measurements (red) and predictions (blue)
Figure 20: Statistics window
In order to create the comparison, a power prediction is performed along the measurement route. For each point i a prediction error ei is calculated as the difference of measured
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7 Measurements
median path loss and predicted path loss. A negative value denotes a pessimistic prediction, whereas a positive value denotes an optimistic prediction.
The prediction errors of the measurement points along the route will result in following values, which indicate the quality of the prediction:
► eThe mean error , which is the arithmetic average of all prediction errors ei. The mean error can be also positive or negative and indicates whether the prediction was too optimistic or too pessimistic. A value near zero would denote a prediction, which is as often too optimistic as too pessimistic, but it gives no indication on the actual prediction errors. It is a goal to tune this value to be zero.
► The standard deviation σ of the prediction errors which is calculated as
( )
11
2
−
−=∑=
n
een
ii
σ
This value is also always positive and indicates the distribution of the prediction error. It is also considered as goal to minimize this result. Generally, for empirical prediction models, the standard deviation is around 6 dB.
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8 Urban propagation modelling
8 Urban propagation modelling
8.1 Propagation models
There are two strategies for propagation loss prediction:
• derive an empirical formula for propagation loss from measurement
• a deterministic method.
A9155 uses both, propagation models that are based on empirical formulas and deterministic ray tracing models based on geometrical optics.
There are two main models:
• Terrain models: a macro-cellular prediction models category, based on topological databases, morphological data and antenna height. From this category in this project was used the Standard Propagation model.
• Urban models
WinProp-ProMan is an urban propagation model performing predictions based mainly on building databases generated by the building database management tool WinProp-WallMan. The urban propagation model can be used for these different propagation applications:
• Microcellular coverage in urban environments with antenna heights below the rooftops and cell ranges of typically a few hundreds of meters
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8 Urban propagation modelling
• Minicells coverage in urban environments with antenna heights above medium rooftop level (surrounding buildings higher and lower) and with cell ranges up to 2-3 kilometres
• Macrocellular coverage in urban environments with antennas mounted on top of buildings higher than surrounding buildings and on masts with cell ranges of tens of kilometres.
In the different environments distinctions of the propagation models are required both in terms of the dominant physical propagation phenomena and the specification of the used database. The urban propagation model can also be tuned and adapted to measurements.
The urban propagation models implemented in WinProp-ProMan are the following:
• Empirical COST 231-Walfisch-Ikegami model: considers only the propagation in a vertical building profile for path loss prediction
• 2x2D empirical model: in the horizontal plane uses the IRT model and in the vertical plane is using the COST 231- Walfisch-Ikegami model
• 2x2D real model: the pre-processing and determination of propagation path is performed in horizontal and vertical plane, in both planes using ray optical methods
• 3D-IRT (Intelligent Ray Tracing) model: computes propagation path in three dimensions.
For more details on the urban propagation models please refer to [6] and [7].
8.2 Settings
The building database was pre-processed with WinProp-WallMan using the following settings:
• Area 5.64 skm (2.45kmx2.3km)
• 10m resolution
• spherical zone adaptive (400m plus 8m/m)
• enhanced resolution management with factor 4
• including topography.
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8 Urban propagation modelling
Each urban propagation model uses a specific pre-processed database.
For detailed information concerning the WallMan module please refer to [8].
The used WinProp-ProMan settings different from the default values are:
• Database tab: see the offset settings in figure 22
Figure 21: Database settings for WinProp
• Prediction: exponent before breakpoint = 2.6
• Postprocessing: including indoor prediction, without linear transition and filter
• Hybrid model: maximum distance for linear transition=500m.
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8 Urban propagation modelling
8.3 Models comparison
Measured3_2_46_30: SPM 900 Measured3_2_46_30: COST-Walfisch-Ikegami
Table 10: Propagation model comparison - SPM900, CWI
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8 Urban propagation modelling
Measured3_2_46_30: 2D real Measured3_2_46_30: 3D-IRT
Table 11: Propagation model comparison - 2D real, 3D IRT
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Conclusion
The different propagation models give different predicted results. Urban models are more accurate than terrain models, and deterministic models are more accurate than empiric models. In this specific comparison, the accuracy increases in the following order: SPM900, CWI, 2D real, 3D-IRT.
Therefore, different propagation models are suited for different environments. For example, urban models can increase the accuracy given by SPM in urban areas on the basis of using an accurate building database, whereas SPM is more suited for suburban and rural areas.
For a more detailed comparison between the propagation models implemented in A9155 please refer to [9].
END OF DOCUMENT
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