When conducting experiments with real hardware in a physical environment, there is frequently an exploration phase during which wireless nodes are moved and applications are run in an interactive fashion. For instance, a transmit rate selection experiment between a laptop and an access point would likely include a phase where the laptop was moved around and performance observed in an interactive fashion. The emulator makes it possible to perform this exploratory phase without the need to actually move around the real world. We provide an interactive GUI that can be used to move RF nodes around in an emulated physical environment and in the corresponding emulated signal propagation environment. The GUI can be enabled even when programmatic or scripted control is in use, for example to visualize an experiment. Several useful experiment controls are also available in GUI, including moving nodes to a different location, creating a route, changing path fading model.
Once you have started an Emulator experiment you will be given a URL from which you can start the GUI applet.
Copy and paste this URL into your internet browser.
After successfully connecting to the server you will then be asked to enter your reservation password. Make sure that the login name matches your own.
Once the server acknoledges that you entered the correct password, the GUI will start.
The World Viewer will load up when you first start up the GUI. The World Viewer is a top-down 2D view of the Emulator world. The vertical dimension of the physical world is not visualized, but is still present in the emulation. Through the World Viewer you can observe and control node movements.
You can scroll around the map by just clicking and dragging on the map background similar to the interface of Google maps.
The panel on the side also helps in Map Control. Moving the slider up and down will let you zoom in and out, respectively, of the map. You could also use your mouse wheel to control zoom. By clicking on the button right below the slider you will center back to the origin.
There are several ways of moving a node manually in realtime through the GUI. You can either use the cursor, create a route, or drag the node.
To move a node using the cursor click on the desired location on the map. This moves the cursor (a red X) to that location. Next highlight a node by clicking on it. After clicking on a node, a menu at the bottom pops up where you can specify the speed you want this node to move. Now after pressing the Move button the node will move to the specified destination at the specified speed.
You can make a node move around a route. To create a route click on a location on the map moving the cursor to that location. If you now click on another point on the map while holding down the CTRL button, you will have created a small two-waypoint route. You can add more waypoints in the same manner by clicking and holding the CTRL button down. To now move a node around this route, highlight a node by clicking on it then choose the wanted speed on the bottom menu then click on the Move button.
You can further edit the route by clicking and dragging waypoint. You can also delete a waypoint by selecting a waypoint then pressing DELETE. Also if you wish for the node to move along a continuous route in a loop you could check of the loop checkbox located at the top of the World Viewer.
You can drag a node by highlighting a node by clicking on it. You can then click and drag the node around the map.
You can disable manual node movement (if for example you only want to observe the nodes) by toggling WorldViewer > 'Nodes Moveable'
You can load a map from a URL by going to WorldViewer > Map Settings. After entering the URL and clicking Load Map button the picture you specified will load up (Note: Currently only picture files located on the server emucontrol-1.ece.cmu.edu can be loaded into the GUI).
Once it is load up you can adjust the size of the picture relative to the grid as your picture will not necessarily have the correct dimensions. You do this by creating a route as you would normally and then specifying how many length in meters this route should be. Once you press Apply, the picture will automatically change dimensions.
Pressing the main OK or Apply Buttons now will load this map up into your main World Viewer window.
You can toggle whether there is a grid or not by checking/unchecking WorldViewer > Grid
You can toggle whether there is a ruler or not by checking/unchecking WorldViewer > Ruler.
You can view various stats of a node by clicking on the View Nodes tab on the menu bar and selecting which node you want to view.
In this view you can view the Nodes destination, the node's velocity and antenna direction.
You can view various channel stats of a particular node pair by clicking on the View Channel tab on the menu bar and then picking your source node and destination node from there.
The Channel View window provides a visual representation of the current impulse response between the source and destination nodes. The fading model in use may be altered by selecting a new model from the drop down control on the lower right.
A real-time graph of the channel path loss may be viewed by clicking on the "View Graph" button on the lower left.
The Path Loss graph displays the current path loss of the given channel in real-time.