Atoll v2.2 AFP Introduction

NORTEL NETWORKS CONFIDENTIAL

Atoll AFP Introduction

Presented by:

Dirk LambertWireless Network Engineering

October, 2004

Atoll AFP Introduction - 2NORTEL NETWORKS CONFIDENTIAL

Atoll 2.2 GSM/EDGE Features

• Features for GSM/GPRS/EDGE projects• Data model• — All the TRX type parameters have been introduced in the subcells• — It is now possible to exclude channels from the allocation at the subcell level• — The separations are now imposed between subcells

• BSIC notation• — It is now possible to manage the BSIC (NCC-BCC) in octal or decimal (as before) format.

• Improvements in traffic modeling• — New ‘data’ traffic layer allowing the modeling of the GPRS traffic demand, in addition to the existing

voice traffic layer.• — Combined GPRS/voice traffic dimensioning and analysis.

• New GPRS features• — Enhanced time slot dimensioning.• — Calculation of Quality of Service indicators

• AFP tool• — An Erlang based cost function replaces the pair-wise sum-up of interferences with a more precise

modeling of the interfered traffic. • — When the constraints are too important for the planning algorithm, it is possible to access to

information giving the list of cells for which the constraints are not fulfilled.• — Predefined MAL are supported (SFH TRX)• — Multiple reuse pattern constraints• — Grouping constraints may be taken into account in non-hopping TRX• — Minimal change optimization (cost of changing already assigned TRX higher than new assignments)• — Staggered MAIO allocation ( MAIO equally spaced for one sector)• — Local quality target (ability to improve plan only where minimal quality is not achieved)

• Consistency checking tool• — The consistency checking tool has been enhanced. Additional tests are automatically provided


Atoll AFP High-Level Process

Define Parameters

Define Network ParametersFreq Band

Freq domain (BCCH,TCH)BSIC domainHSN domain

Cell Type

Define AFP Parameters

Define Planning Recourses & Constraints

Apply Cell Parameters# of TRXsCell Type

HSN DomainBSIC Domain

RUN AFP

Validate Results

Create/load Neighbors


Overview• ATOLL AFP model supports Base Band Hopping (BBH) and

Synthesized Frequency Hopping (SFH) modes. It enables you to automatically generate frequency plans for GSM and TDMA networks. The following parameters may be allocated:

• Frequencies• Frequency hopping groups (MAL)• HSN, MAIO• BSIC

• Notes : • An audit on the computed frequency plan is available.• A channel search tool working on channels, BCCHs and BSICs allows

you, for example, to display the transmitters cells with a specific frequency (f) the ones with frequencies (f+1) and (f-1) in different (adjacent) colors.


Overview• The AFP aim is to generate optimal allocations, i.e. allocations

that minimize interference over the network and comply with a set of constraints defined by the user. The two main types of constraints are the separation constraints and the spectrum limitations. The AFP uses a ‘cost function’ to evaluate frequency plans, and the aim of the algorithm is to find frequency plans with minimal costs.

• Before starting an AFP session, you have to insure that the number of required TRXs per transmitter has been already defined. The related traffic loads have an effect on the cost function used in the AFP.

• As separation constraints may be set on neighbors, this allocation should also be performed before starting an AFP session.


Network Settings• Prior to initiating the AFP tool,

the user needs to define a few Network parameters. These are as follows:

• Frequency band• Frequency group• Frequency domain• BSIC domain• HSN domain• Cell Type• # of radios per TRX


Frequency Band• To open the frequency band dialog, proceed as

follows :

• Left click on the Data tab of the Explorer window,

• Right click on the transmitters folder in order to get the related context menu,

• Choose the Properties option from the open menu,

• Click on the Frequencies tab,• Either

• Select the frequency band you want to manage,• Click the modify button to open the associated

dialog,

• Or,

• Double click the frequency band you want to manage.

• Click the General tab,• Define the frequency band parameters,• Click OK to validate your choice,• Click again OK to close the transmitters

properties dialog box.


Frequency Domain• To define domains and groups of frequencies,

proceed as follows :

• Left click on the Data tab of the Explorer window,• Right click on the transmitters folder to get the related

context menu,• Choose the [Network settings : Domains : Frequencies…]

command from the open menu,• In the Domains dialog, enter a domain per line and

specify the related frequency band. To validate a domain creation, select another line.

• Either

• Select a domain in the table and click on the Properties… button.

• Or• Select the line relating to a domain and double click on it.• In the domain properties dialog, specify the name of

groups that you want to associate to this domain and define for each of them:

• - The lowest available frequency (Min channel number),• - The highest available frequency (Max channel number),• - The value interval between the frequencies (Step

between channels),• - Frequency (frequencies) you do not want to use

(Excluded channel numbers). You can paste a list of channels; separator must be a blank character,

• - Additional frequency (frequencies) you want to consider during allocation (Extra channel numbers). You can paste a list of channels; separator must be a blank character.


Frequency Groups• You can also define the domain-group pairs

in the Group of frequencies window.

• To do so, proceed as follows :

• After defining all the domains, close the Domains dialog,

• Right click on the transmitters folder to get the related context menu,

• Choose the [Network settings : Groups : Frequencies…] command from the open menu,

• Use the What's this help to get description about the fields available in the open window,

• In the Group of frequencies window, select a domain and associate one or several groups of frequencies to each of them. Define the groups as explained above.

• The defined domains can be now assigned to TRX types of each cell type in order then to be used as constraints in the automatic allocation of frequencies.


HSN Domain• For an easier resource management, HSN domain and group tables are available. HSN domains are

linked to types of TRXs. When defining a cell type, you must assign a HSN domain to each TRX type.• To define domains and groups of HSNs, proceed as follows :• Left click on the Data tab of the Explorer window,• Right click on the transmitters folder to get the related context menu,• Choose the [Network settings : Domains : HSNs…] command from the open menu,• In the Domains dialog, you can enter a domain per line. To validate a domain creation, select another

line.• Either• Select a domain in the table and click on the Properties… button. Or• Select the line relating to a domain and double click on it.• In the domain properties dialog, specify the name of group (s) included in this domain and define for

each of them:• - The lowest available HSN (Min),• - The highest available HSN (Max),• - The value interval between the HSNs (Step),• - HSN (s) you do not want to use (Excluded). You can paste a list of HSNs; separator must be a blank

character,• - Additional HSN (s) you want to consider during allocation (Extra). You can paste a list of HSNs;

separator must be a blank character.

• Note : A default domain called “ALL HSNs” exists; it contains the 64 HSNs.• You can also define the domain-group pairs in the Group of HSNs window. • To do so, proceed as follows :• After defining all the domains, close the Domains dialog,• Right click on the transmitters folder to get the related context menu,• Choose the [Network settings : Groups : HSNs…] command from the open menu,• In the Group of HSNs window, select a domain and associate one or several groups of HSNs to each

of them. Define the groups as explained above.• The defined domains can be now assigned to TRX types of each cell type in order then to be used as

constraints in the automatic allocation of HSNs.


Cell Type• Cell types are linked to station templates or

transmitters. Indeed, when defining a station template or transmitter properties, you must specify the cell type which the station or transmitter refers to.

• Cell type properties can be accessed in two ways, either from a Cell type table, either from a Cell type dialog.

• To open the cell type dialog, proceed as follows:• Left click on the Data tab of the Explorer window,• Right click on the transmitters folder in order to

get the related context menu, • Choose the Properties option from the open menu,• Click on the Cell types tab,• Either• Select the cell type you want to manage,• Click the modify button to open the associated

dialog,• Or,• Double click the cell type you want to manage.• Click the General tab,• Define the cell type parameters,• Click OK to validate your choice,• Click again OK to close the transmitters properties

dialog box


Neighbor Allocation• Allocating automatically permits to allocate

neighbors globally in the current network by imposing constraints on active transmitters that must be satisfied. Force neighbor reciprocity, adjacency and within co-site is possible.

• To automatically allocate GSM/GPRS/EDGE neighbors in a network, proceed as follows :


• Right click on the transmitters folder to get the related context menu,

• Choose the [Neighbors: Automatic allocation...] command from the open menu,

• Use the What's this help to get description about the fields available in the open window,

• Set the parameters for the current Auto Neighbors allocation study


AFP • To start an AFP session, proceed as

follows:


• Right click on the transmitters folder or on a group of transmitters,

• Choose the [Frequency plan: Automatic allocation…] option from the context menu,

• The first step consists in setting AFP inputs such as the resources to allocate, the choice of the subcells to be considered, and the separation requirements. During the second step, Atoll loads and checks the network. The third step consists in optionally computing the theoretical level of interference that the AFP model will have to minimize.

• NOTE: If you choose not to make this calculation, the mathematical model will work with respect to separation constraints ONLY. This dialog will allow you also to set the AFP model and to run it. Finally, Atoll provides AFP results in the last step.


AFP Generic Input Window • After having started an AFP session, the 1st

step consists in the AFP generic inputs.

• In the General tab, check the boxes related to the resources you wish to allocate during this AFP session. It is possible to allocate several resource types: channels (for NH or BBH subcells), MAL and MAIO (for SFH subcells), HSN (for BBH and SFH subcells) and BSIC.

• Note : Atoll avoids creating TRXs without channels. Therefore, if the user does not ask for MAL-MAIO assignment, all the SFH subcells are considered as “frozen”, and no TRXs will be created for them. The same happens in case only a MAL-MAIO assignment is selected. In this case, all NH and BBH subcells will be seen as frozen and no TRXs will be created.

• Then, indicate if you want all the potential interferers to be taken into account by the AFP model. Check/uncheck the ‘Load all the potential interferers’ box. If this box is unchecked, the cost function will only consist of the separation violation cost.

• In the Separations tab, click on the Exceptional pairs… button in order to check/add separations within exceptional pairs of transmitters and subcells. These separation constraints have priority on other separations (co-cell and co-site separations as well as separations between neighbors) you may specify.

• Then, define the channel separations within subcells of a same cell, within subcells of co-site transmitters and between subcells of neighbors. You may specify separations between BCCH subcells, traffic subcells and between BCCH and traffic subcells.

• Click Validate to run the loading of the selected network and its checking.


AFP Validation

• After having loaded and checked the involved network, Atoll opens a dialog made of three parts.

• The first part reports the validated network conditions :

• — Resources to be allocated,• — Separation constraints,• — Type of the loading

• · Full : both potential interferers (interferences taken into account) and transmitters/subcells considered in separation requirements have been loaded and checked.

• · Partial : only transmitters/subcells involved in separation requirements have been loaded and checked.

• — State of the network loading : number of loaded subcells, number of subcells selected for the AFP process, warnings during the consistency checking, etc…

• NOTE: At this step, the status box in the part “Step 3” indicates that the allocation will be based on separation constraints only.

• Be sure this is what you want!


AFP Interference Matrix

• The second part of the dialog enables user to calculate/import interference histograms interferences are taken into account in AFP (not only separation requirements). Interference histograms can be computed only if the user has previously selected the option “Take into account interferences” (leading to the loading of all the potential interferers) in the previous dialog. Else, buttons are greyed.

• In the first case, for each pair (interfered subcell, interferer subcell), Atoll calculates a C/I value on each bin of the interfered subcell service area (determined by the min reception threshold defined at the subcell level); all the subcells are supposed to share the same channel. Then, Atoll integrates C/I values calculated over the service area of the interfered subcell and determines an interference histogram. Histogram shows the different interference probabilities. Interference probability is the probability that users of the interfered subcell receive a C/I higher than a C/I value; interference probability is stated either in percentage of interfered area or in percentage of interfered traffic.

• To calculate interference histograms, proceed as follows :• Click on Calculate… to compute interference histogram for each pair of subcells,• In the Interference calculation dialog, specify the servers to study (All, best signal

level per HCS layer), a margin in case of a best signal level study and choose how to define the interference probability, either in percentage of interfered area or in percentage of interfered traffic.

• Then, click on OK to run the interference histogram calculations.


AFP (Properties)

• In the property dialog of the Atoll AFP model, you may manage some parameters to be considered in the cost function and in addition, give some directives to the AFP model.

• To open the Atoll AFP model property dialog, proceed as follows :

• Either

• In the Modules tab, open the Frequency allocation modules list,• Right click on the Atoll AFP Module subfolder,• Select the Properties command in the context menu.

• Or• Right click on the Transmitters folder,• Select the [Frequency plan: Automatic allocation…] command from the opened

scrolling menu,• In the second dialog (after the loading of the network), select the model in the

scrolling box,• Click the Properties button.

• Note: Like for the propagation models, it is possible to duplicate the AFP model with different sets of parameters. They will be available in AFP sessions (once duplicated, the model is then available in the AFP scrolling list of the generic AFP dialog).

• The AFP property dialog consists of 7 tabs : the General, Cost, HSN, MAL, MAIO, BSIC, Advanced. The Cost and Advanced tabs include parameters to take into account in the cost function estimation. The other tabs refer to the allocation strategies on HSN, MAL, MAIO and BSICs required to the AFP.


AFP Properties Option Tabs


RUN AFP

• Once all the parameters are set you can set a time constraint and activate the AFP. You can choose to commit the plan once it’s completed or it can be discarded.

• Atoll provides a tool which allows you to search for BCCH and/or non BCCH channels and BSIC. This is an additional tool to analyze a frequency plan; you may use it in order to quickly visualize channel and BSIC reuse on the map.

• To display the Search window, select the "Channel search window" in the View general menu. Atoll opens a floating window that you can keep at any location on your screen, or dock at the bottom of the map, like the Point analysis window.

• The user defines a channel or a BSIC, Atoll finds and highlights (by allocating significant colors) the transmitters which are assigned that channel or BSIC.

• Three tabs are available to help the user find transmitters which are assigned a given channel, BSIC or BCCH-BSIC. Atoll changes the colors of the transmitter arrows on the map. To obtain a 2D graphic display, it is necessary to have preliminary defined and calculated a study "Coverage by transmitter" (with a color display by transmitter). The colors of the coverage cells will then follow the colors of the transmitters.


RUN AFP


ATOLL AFP INTRODUCTION

• NOTE: All info presented here can be obtained in iPlanner’s help menu

Atoll v2.2 AFP Introduction

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