EDX Multipoint Studies (not available in EDX Signal) use a Transmitter/Base/Hub/Router site (see Edit Transmitter Group) at one end, and a fixed location/receiver at the other. Multipoint Studies are different than a point to point link in that the transmitters may be able to talk to and serve multiple fixed locations at a time.

The advantage of Multipoint Studies is that the height, directional antenna, receiver equipment type, and other properties of each CPE can be individually specified. Because of this advantage, Multipoint Studies are ideal for studies involving fixed WiMAX, SCADA and wireless local loop systems where a number of hubs or base stations serve an array of fixed rather than mobile locations. With Area Studies, described later in this chapter, all mobile/remote units placed at each study point share the same parameters. As a result, you cannot specify different mobile/remote units in the same area study.

Multipoint Studies are intended for use when you want to find the signal levels, signal-to-interference ratios (C/(I+N)) and other relevant radio link performance information, from one or more base stations at a number of fixed locations. These can have various names: customer premise equipment (CPE), subscriber unit (SU), fixed subscriber, meter, etc. Currently, EDX uses the term CPE to refer to fixed locations/equipment used with a multipoint study. CPE Data may be added and edited either through the RF Systems>CPEs (see Customer Premises Equipment (CPEs) and CPE Types) or through RF Systems>Spreadsheet Editors>CPE Data (see Spreadsheet Editor).

To set up a multipoint study, select Studies>Multipoint Studies which opens the following Multipoint Studies for Map View dialog box. This dialog box allows the user to display and modify the multipoint studies that have been set up, as well as add new studies and delete current studies. In addition, study results can be exported to CSV (comma-delimited Excel spreadsheet), KML (Google Earth vector) and MIF (MapInfo Interchange Format) files.

Calculate/Current/Group/Name/Transmitter Group/CPE Group/Label

For each study listed in this dialog box window, you’ll see the 6 columns listed in the title of this section. The Calculate column checkbox toggles whether that particular study will be calculated on the next multipoint study run. The Current column checkbox determines which study will be shown at each CPE location in the main map window. Only one study can be shown at a time. The Name column displays the name of the selected study. The last two columns show the Transmitter Group and CPE Group on which the study will run. For more information on groups and grouping, see Transmitter/Base/Hub/Router Sites and Customer Premises Equipment (CPEs) articles respectively.

The Label field allows you to enter a unique identifier for each study listed. This can be useful if you’re running the same study on different groups. For example, if you set up and run 4 Received Power at remote studies, you’ll see Received Power at remote listed 4 times in the Map Layers list. You won’t know which one is which at the moment. Giving each their own label makes it easier to identify them in the Map Layers list.

Define Multipoint Groups

Clicking the Define Multipoint Groups button displays the Multipoint Study Groups dialog box. If you’ve set up groups of CPEs, this allows you to specify up to 5 groups for use in the Multipoint Studies. When you choose a group, it’s reading from the RF Systems>CPEs list of groups.

Study Results Based on:

EDX software has a basic product version, as well as add-on design modules for features like WiMAX, LTE and Mobile and Cellular. These additional design modules (not available for Signal) use methods to preprocess the customer units (CPEs) in order assign them to the transmitters (See Chapter 26, Multipoint Network Design Feature). At the end of that process, CPEs are assigned to a specific transmitter and that assignment is updated in the CPE details. If you don’t have one of the above-mentioned design modules, then during multipoint studies, an automatic assignment takes place based on the strongest server. The Study Results Based on section allows you to select whether the CPEs are assigned to the strongest server calculated during the study (Strongest Server) or the CPEs have been manually assigned to a server or automatically assigned via the above mentioned design modules (Assigned Server). The Assigned Server and Strongest Server radio buttons allow you to switch between the two modes.

Link Studies From CPEs to Servers

Clicking the Link Studies From CPEs to Servers button will run a link study from each transmitter to all its CPE’s, then create a text report listing each CPE and the link details for each connection. The report includes the CPE/Site information along with path length, fade margins, % availability, RSSI, etc. To view this report, go to Utilities>System Reports and select your report from the list. You can also find it in your project folder, located in the \reports\ subfolder.

Add Study

The Add Study button is used to add studies to the dialog box list. Appendix F describes in detail the methods used for each study name.  Clicking the Add Study button brings up the following Multipoint Study Details dialog box where you can set up your multipoint study.

Study Group/Study Name

This is where you pick the study you want to set-up and run. Clicking the Study Name drop-down list allows you to see the full list of multipoint studies that are available in your product. Notice that the default Study Group is set to Basic. This is the group of studies that are available in the basic EDX software products (Signal and SignalPro). If you are running SignalPro and have any of the add-on design modules such as WiMAX or Mobile and Cellular, clicking on the Study Group drop- down list will show additional study groups, such as Multipoint, WiMAX/Wireless Broadband or 3G PCS/Cellular. Selecting one of these other groups, then browsing the Study Name drop-down list will show additional studies available through that module. 

Transmitter Group/Multipoint Group

If you’ve sorted your transmitters and CPEs into groups, clicking the Transmitter Group drop-down list allows you to select which transmitter or CPE group to use when running this study. If you haven’t sorted your transmitters or CPEs into groups, then by default the study will run on the master group, and will include all transmitters marked as active in the group and all CPEs in the master group.

Remember, the multipoint groups that are available have to be pre-specified by using the Define Multipoint Groups button in the previous dialog box.

Study Display Style

 Clicking the Study Display Style button bring up the Multipoint Study Map Layer Style dialog box where you can set how the study will look on the main map. The Symbol drop-down list and Point size box determine the shape and size of the study results placed at each CPE location. However, if you select the Strongest (most likely) Server Study Name in the Multipoint Study Details dialog box and then click the Study Display Style button, a Multipoint Study Map Layer Style dialog box displays that does not have a selection button for either Set signal/color levels or Set color theme as default but instead has a Use Channel Color checkbox to toggle using the channel color for the study result. 

Set Signal/Color Levels

The Set signal/color levels button brings up the following dialog box where you can set the number of levels you want to see in your study. Depending on which Study Name was selected in the previous dialog box, the number and type of Set signal/color levels options displayed will vary, and may be limited. For example, selecting the Shadow map study bring up a dialog box where you can only have two levels: LOS and Shadowed. 

Selecting a Received power at remote study brings up a dialog that allows you to set up to 10 different levels. Type in the number of levels you want and hit tab to exit the field and set the new levels. Set the color for a level by clicking the Color box for that level. 

Clicking the Symbol drop-down list allows you set a different symbol to be painted on the screen. However, leaving it the solid color is usually the best option for study clarity. At the bottom of the Symbol drop-down list is a (blank) NO_SYMBOL choice, which can be useful in certain circumstances. For example, you’re running an RSSI study where all you care about is signal above a certain threshold, like -90dBm. You can’t have less than two levels, so normally you’d be stuck with color in the display below the threshold in which you’re interested. However, selecting the NO_SYMBOL for the results below your threshold will effectively remove them from the final display. You’ll still see the results in the status bar, but not on the screen.

The Values column is where you type the numbers that represent the edges of the ranges you’re interested in showing. 

The Description column allows you to add notes for each level that can be displayed in the legend window next to the signal level.

Set color theme as default

EDX software has defaults color settings for all the studies that return a colored display for the result. Clicking this button will overwrite the EDX defaults color scheme for this study name with what you’ve set for this study. It won’t override the colors of existing studies, but will apply to any new study you add. You can also change the defaults manually. For more information, see the Study Preferences.

Signal level display threshold

The next item in the Multipoint Study Details dialog is the Signal level display threshold input field. This threshold value will limit the multipoint study display based on whether the signal received at the CPE from the base is above or below this threshold. By selecting an appropriate value here, you can suppress the display of any study results where the received signal level is below the entered threshold value. See Appendix F to understand exactly how this value is used in calculating and displaying a study.

Limit MLS.../Include MIMO.../Limit Calc Distances...

The Limit MLS... checkbox works with the Approximate sector range field value located in the Study Sector dialog box, which is accessed by clicking the Study sector/Sector range button in the Transmitter/Base/Hub/Router Site Details main dialog box. When checked, it limits the sector calculation range to what is set in the Approximate sector range field.

The Include MIMO... checkbox works with the MIMO/Adaptive drop-down list settings in the Transmitter/Base/Hub/Router Site Details main dialog box. When checked, it will use the chosen MIMO/Adaptive type selected. If no MIMO/Adaptive type has been selected (None), then it’s not included in the calculation.

The Limit Calc distances... checkbox uses the Study radius field value located in the Study Sector dialog box, which is accessed by clicking the Study sector/Sector range button in the Transmitter/Base/Hub/Router Site Details main dialog box. When checked, CPEs outside this Study radius distance will not be considered during calculation.

Noise and Interference option for C/(I+N) and BER studies

For most C/(I+N) calculations, you will also see a set of radio buttons that give you the option of choosing which quantities are used in the denominator. For some types of analysis, it is helpful to see C/I only or C/N only to get a view of the extent to which interference or noise alone is affecting the received signal.

Availability Method

The Availability Method drop-down list allows you to choose the method that calculates reliability (or availability) for the studies. The parameters and settings for the chosen method are set under Studies>Reliability Methods. To make informed selections using this drop-down list, you should first review Appendix H, that describes in detail the ramifications of each selection.

Modify Study

Returning to the Multipoint Studies for Map View main dialog box, after a study is highlighted in the list, selecting the Modify Study button opens the Multipoint Study Details dialog box to allow study modifications. The fields in this dialog box are the same as those available when selecting the Add Study button.

Delete Study

For any study selected in the list, clicking the Delete Study button deletes the study and corresponding study layer from the map layers. 

Run Studies

Clicking the Run Studies button will start the calculations for all studies in the list that are checked in the Calculate column. You can also run the studies from the main map window by clicking on the Multipoint study buttonin the toolbar menu. Another option is to use the project pane: expand Map Views>Initial View>Multipoint Studies and right-click on the study you want to run. A contextual menu displays selection options for the study. Choose Run to start the study .

Following this action, a series of dialog boxes will appear. This first dialog box reports the progress of the study as it calculates the signal levels from each hub transmitter to each CPE. When these calculations are done, it will report that it is doing the final composite calculations for the study. If necessary, you can cancel the study operation. However, if you do so, any display results for that study will be removed from the screen until you re-calculate the study. When the Multipoint Study is completed, the results will appear as colored symbols on your map at each CPE location, as well as in the dialog for each CPE. Thematic study result colors can also be shown for the CPE-Hub link lines on the main project map. See Appendix F for more information on how Multipoint Studies are done.

When you have displayed a Multipoint Study, you can right-click on any of the displayed CPEs to view the CPE parameters, investigate the actual paths to the assigned or focus sectors, display the study results table for that CPE, see and control the group membership and copy or delete the CPE. If the CPE you want to investigate is physically close to another object on your map, you may have to hold down the “C” key as you right click. You might first see a dialog box that will list the CPEs found near the location where you right clicked. Move your mouse to the one you want to select.