Simulation Monte Carlo in Netact

8/13/2019 Simulation Monte Carlo in Netact

1/16

Monte Carlo Simulation

1.1 What is Simulation?

Static Simulation is a method where the performance of the network is analysed over multiple

instances in time or "snapshots", where specified densities of user equipment (terminals) arepositioned in statistically determined locations for each snapshot. The ability of each terminal tomake its connection to the network is calculated through an iterative process. epeating ananalysis with the same inputs may give different results.!arious connection failure conditions are considered, for eample#

$aimum mobile power eceeded

$aimum node power reached

%o available channels

&ow pilot S' for $TS or &ow pilot c*'o if using +$-/// or T0S+$-

The performance of the network is then analy1ed from the results of a series of snapshots.

The Simulator in -SST23 uses the Static Simulation method.

1.2 Monte Carlo Simulation

Traditionally, T$-*4$- network planning used static analysis and calculated the margins for atuned propagation model to allow for interference. 5owever, since the level of intra0cell and inter0cell interference varies between cells, this approach gave misleading results in early networks.Therefore, in +$-0based networks, such as $TS or +$-///, it is often better to use othermethods to predict coverage and cell capacity.

-n alternative approach has been developed based on simulating networks using $onte +arloalgorithms, and -SST23 uses this approach as it provides a good balance between accuracy

and usability.

uring the simulation#

- large number of randomi1ed snapshots are taken of network performance for different

user equipment (terminals) over time. 'n these snapshots, the terminals are positioned instatistically determined locations and generated independently for each snapshot.

The number of terminals in an active session in a piel is determined using a 6oisson

distribution with a mean given by the number of terminals in the traffic array. This means


2/16

that the total number of terminals in a snapshot is 6oisson distributed and so it will varyfrom snapshot to snapshot.

These snapshots are then used in calculations to obtain statistically valid measurements

giving an estimate of the mean network performance.

epeated simulations can prove valuable for detailed optimi1ation of site configurations, problemareas and radio resource management algorithms.

1.3 Prerequisites for running Simulation

7efore simulating your -SST23 network with the Simulator, ensure you have#

+reated the network as required, assigning antennas and propagation models to the

cells, and setting the appropriate site and cell configurations.

Set up carriers, bearers, services and terminal types.

+reated coverage predictions and coverage arrays.

+reated a traffic raster for the terminal type(s) you would like to be included in the cell

loading calculations (that is, in the snapshots).

+hosen whether you want to perform batch runs or set up distributed 6+s (8./ Simulator

only).

1.4 The Snapshot Process

- snapshot represents an individual component within the simulation process. -t the start ofevery snapshot, the terminals are distributed in statistically randomi1ed positions. ach

sequential snapshot analyses the network performance based upon on its own particulardistribution of the terminals.The number of snapshots specified in the Simulation +ontrol 6anel will be run when you start thesimulation.This list indicates what is happening within each snapshot when the simulation is running#

-t the start of the snapshot, the terminals are randomly ordered to ensure no biasing of

results (since the terminals are sequentially tested during the snapshot).

The terminal and cell powers are initiali1ed to 1ero and these are then used to initiali1e

the noise on the uplink and downlink. 9ther parameters such as power control error areset randomly on every terminal.

+orrelated fades to the covering cells of a terminal are generated, according to the

values set in the Simulator wi1ard.

%ote# Shadow fading is calculated independently for every combination of cell and terminal inevery snapshot. This means that within a snapshot in a piel two terminals may have differentpath losses to a cell.

The first terminal in the list is tested for failure conditions. 'f it does not fail, then its T:

power, and the T: power of the cells to which it is connected, are modified.


3/16

The net terminal in the list is then tested for failure conditions, and so on.

;hen the entire list has been tested, the simulator returns to the first terminal and

repeats the process. This continues until convergence is reached.

;hen convergence is reached, the results of the snapshot are appended to the results of

the overall simulation.

The simulation then moves on to the net snapshot.

;hen the simulation has completed all the specified snapshots, you can view your results usingthe arrays or view a summary of the data or reports, or you can choose to run more snapshots.

1.5 unning the Simulator

Select the area for the simulation either by clicking on the open $ap !iew or entering the co0ordinates manually, then click %et.

nter the simulation parameters. -lternatively, you can use the default values by clicking theefault button. +lick %et.


4/16

Select the filter(s) you want to include in the simulation, and then click net.


5/16

Select the terminal type(s) you want to include in the simulation.

There are three possible


6/16

The final step displays a summary of all your parameters and the total memory requirements. 'fyou do not have enough physical memory to run the simulation, you should go back and edit theparameters, or consider closing any other applications that are running on your machine.

'f you want the simulation to automatically include all possible array outputs that are relevant tothe inputs and the chosen region, select the 6erform 9utput -rrays -uto Setup checkbo.


7/16

'f you are satisfied with the summary, click 4inish to close the wi1ard.

-SST23 allocates memory and loads the parameters. ;hen this is complete, the Simulation

+ontrol 6anel dialog bo appears.

?ou now have a simulation in memory that represents an "unloaded" network. Some arrays areavailable for analysis at this stage.

?ou are now ready to run snapshots to create a simulation of a "loaded" network.

1.! unning the Simulation

;hen you have completed and closed the Simulator wi1ard, and after -SST23 has allocatedmemory and loaded the parameters, the Simulation +ontrol 6anel appears.To run the snapshots#

>. 'nsert the initial number of snapshots you require.

%ote # ?ou can choose to run more snapshots to the same simulation at any time.

@ or @

'nsert the A8= confidence interval in d7.


8/16

. +lick un.

;hile you are running a simulation, you can use the Simulation +ontrol 6anel dialog bo to viewthe progress of the simulation, in terms of the number snapshots and the time taken.

The Simulator will run until the specified number of snapshots has been completed. ?ou can alsoclick Stop at any time, if you want to view interim results. ?ou can then continue the simulation byclicking un again. The accumulated results of all the snapshots completed so far are saved inmemory, until you either close the proBect, or choose to start another simulation.

?ou can save the results of any stage of the simulation by clicking Save. ?ou can also set up anautomatic save option when you are using the Simulator wi1ard, or you can edit the auto0save byclicking the 6roperties button.

?ou can pause, continue and restart a simulation using the Simulation +ontrol 6anel dialog bo.This dialog bo appears after you have set up all the parameters using the Simulator wi1ard andloaded in the necessary data.


9/16

;hen you have run a simulation, or loaded a simulation from a file, you can view a summary ofthe simulation data. To do this#

'n the Simulation +ontrol 6anel dialog bo, click 6roperties.- summary dialog bo displays various parameters about the simulation, such as total number ofterminals, number of serving cells, convergence criteria.4or information about these parameters, see -bout the Simulation 6arameters.

?ou can also change the options for the 7ackup parameters and the 6assive Scan Terminal (8./Simulator only) and then continue running the simulation, without the need for reloading thewhole simulation. To do this#

'n the Simulator 6roperties dialog bo, click dit !alues.

'f you click on Outputs, this will open the -rray efinition +ontroller. This feature does not createor delete arrays. 'nstead, its purpose is to define a collection of arrays that you might want todisplay for analysis after you have run a simulation. The feature also enables you to customi1ethe names of the output arrays, and categori1es those using folders. The selected arrays can besaved to an :$& file for later retrieval. ;hen youCre finished wit this dialog, click DOkor Cancelto return to the Simulation +ontrol 6anel.


10/16

1." #ie$ing %utput &rra's

se the -rray Settings dialog bo to define the settings that will influence the arrays you wish to

create. These settings can have an important impact on any of the coverage or interferencearrays that you produce.

To open the -rray Settings dialog bo#

4rom the -rrays menu, click -rray Settings.

Set up the threshold in d7m for all simulation arrays that use received pilot strength.

Set a percentage threshold for the


11/16

1.( %utput &rra's

Some e)amples of arra's*

't is possible to use arrays to display the result of simulation. To do this#

>. ;hile the Simulator is running, in the $ap !iew click the Show ata Types button.

. pand the Simulator group and select the checkbo net to whichever array you want todisplay.

2. +lick with the right mouse button directly on the $ap !iew window, and from the menu thatappearsF click edraw to refresh the display. ?ou can do this repeatedly.


12/16

+est ,- Cell ' SCP


13/16

1./ The Pi)el &nal'ser

-fter you have generated some simulation results, you can use the 6iel -nalyser to viewinformation for any selected piel in the $ap !iew window. 7y analysing the effects of each cellon a selected piel, you can improve the network performance.

0ot Tracing ynamically view information about values for any piel on the $ap !iewwindow by moving the mouse cursor over the map. This mode operates dynamically with themouse cursor.

Pi)el Select Select a specific piel by clicking on the $ap !iew window. The displayed valueswill not change until you click on another piel on the $ap !iew. This mode enables you to view apiel


14/16

To customise the content of the 6iel -nalyser window, you can either use the 9ptions menu atthe top of the window, or double0click on the relevant pane.

>) 'n the 6iel -nalyser window, double0click anywhere in the first pane. The Select -rrayows dialog bo appears.

) 'n the -vailable -rrays pane, double0click the arrays you want to be displayed. They willappear in the upper pane.

2) Select the +hart checkbo for each array if you would like the chart to be displayed in the6iel -nalyser window.

G) Set the $in and $a values for the chart by clicking the value boes for the array, andthen entering values.

8) ;hen you have finished, click 9E.

;hen you are satisfied with the options you have set, place the cursor on the $ap !iew, and youwill notice a symbol appears.

To display the information per piel in the 6iel -nalyser window, either move the cursor (if in 5otTracking mode) or click on a specific piel (if in 6iel Select mode).

'n the 6iel -nalyser window, double0click anywhere in the second pane. The Select +olumnetails dialog bo appears and select the columns you wish to display in the 6iel -nalyser.


15/16

?ou can use the 6iel -nalyser to display analysis plots of any vector*polygon chosen from your$ap !iew.

The 9ptions pane of the 6iel -nalyser window enables you to do the following#

Select the layer to view, if multiple technologies or carriers were included in the

simulation. This will display cells of that technology only, and*or using that carrier only.

+ompare cell values over two locations.

-ctivate the vector analysis plot.

1.1 -oaing an Saing Simulation ,ata

?ou can save the simulation results at any time, and then reload them. ;hen you are running theSimulator, the accumulated results of all the snapshots completed so far are saved in memory,until you either close the proBect, or choose to start another simulation.

?ou can save the results of any stage of the simulation by clicking Save in the Simulation +ontrol6anel dialog bo. ?ou can also set up an automatic save option when you are using the


16/16

Simulator wi1ard, or you can edit the auto0save by clicking the 6roperties button in the Simulation+ontrol 6anel dialog bo.

;hen a simulation is saved, the following items are saved#

The simulation status, that is, how many snapshots have been taken.

The simulation parameters, which include the filters of nodes being simulated, the

resolution, all the wi1ard parameters, all the $TS cell parameters, terminal types,service types, bearers, handover and so on.

The simulation results.

?ou can also save simulation data in either of these ways#

sing the $ap'nfo eport. 4or more information on this, see the %T6'S 5elp.

+opying arrays to the array clipboard.

-oaing simulation parameters

?ou can load simulations (results and parameters) from the -rray $anager dialog bo. To do this#

>. 4rom the -rrays menu, click -rray $anager.. Select Simulation and click the &oad button.2. 7rowse to the appropriate folder and select the .2gr file you wish to load.G. +lick &oad in the -rray 4ile Selector dialog bo.

1.11 Writing Simulator Traffic to the Site ,ataase

4ollowing a $onte +arlo simulation, it is possible to write the mean number ofconnections made for each service to the site database. This performs a functionanalogous to capturing traffic using a 3 analysis, but with the added consideration ofsoft and softer handover.

To do this, click onArrays Simulator Write Sim Traffic to Site Database.

Simulation Monte Carlo in Netact

Documents

Transcript of Simulation Monte Carlo in Netact