1. DEUS
Deployment and Ease Use of wireless Services
Propagation Prediction tool
Main challenges
The characterization of path loss in indoor environments has been the subject of
extensive research and many models have been proposed to make accurate predictions.
The WHIPP (WiCa Heuristic Indoor Propagation Prediction) tool is developed for
predicting the wireless coverage for a given set of access points on a certain floor level of
a building, based on the building’s geometry and the used materials. The tool also allows
to automatically position wireless access points in order to meet a given coverage
requirement in the different rooms of the building.
DEUS approach
The following two requirements were kept in mind when developing the tool.
• User-friendliness. The user interface of the application was developed using an
iterative design process in close collaboration with usability experts.
• Accuracy. Measurement campaigns in four different buildings were executed to
construct, tune, and validate the coverage calculation models.
DEUS solutions
The WHIPP tool allows both layman and expert users to predict wireless coverage for
their home or work environment. It is developed for 802.11b/g, with an extension for the
MIMO (Multiple Input Multiple Output) WLAN standard 802.11n.
The coverage calculation is based on a floor plan of the building, which can be obtained
in three ways.
Drawing a floor plan of their home or work environment. After selecting a building
material (brick, layered drywall, concrete, glass, wood, or metal), the user draws
individual walls onto a fixed grid. While the user is free to disable this constraint, the
presence of a grid enables them to quickly create an accurate representation of the floor
layout. To help with the drawing process, the tool supports standard operations such as
’erase’, undo/redo’ and ’zoom’.

2. DEUS
Deployment and Ease Use of wireless Services
• Importing existing ground plans.
• Tracing image scans. Existing building plans come in various digital formats and it
is impossible to create conversion tools for all of them. Therefore, a feature that is
similar to tracing paper is provided in the expert version of the drawing tool. An
image scan of the floor plan can be displayed in the background, allowing the user
to easily trace the walls. In a calibration phase, the user sets the scale of the
image.
All created floor plans can be saved to the local system and opened later for further
editing.
Once the building plan is created, the user chooses the locations of the wireless access
points. At this point, the tool has collected enough information to submit a path loss or
throughput calculation request to the server.
• Path loss [dB], between an access point and a receiver device is the ratio of the
transmitted power to the received power. It includes all of the possible elements
of loss associated with interaction between the propagating wave and any objects
(e.g., walls) between the transmitting and receiving antennas.

3. DEUS
Deployment and Ease Use of wireless Services
To calculate the path loss, the dominant path between transmitter and receiver is
determined. This is the path with the lowest attenuation (the lowest total path
loss) when propagating from transmitter to receiver. It is assumed to 95% of the
total energy is contained in this dominant path. Parameters influencing the total
path loss are the distance along the path, the cumulated wall penetration losses
for all walls traversed along the path, and the interaction loss or the loss caused
by the bending of the path (around corners).
• The throughput [Mbps] is the data rate that is achieved over the wireless channel
between access point and receiver device. It depends on the received power level,
the receiver characteristics, the network load, and the technology. Different
internet activities require different throughputs: video streaming causes a heavier
load on the network than browsing or email.
The tool turns the predicted path loss or throughput into a colour-coded visualisation
superimposed over the floor plan.
• Gives the user a clear view on the estimated wireless connection quality
(coverage) in each area, as shown in the figure. Allows the user to quickly
distinguish areas with adequate coverage from those with poor connectivity.
• Four intervals for throughput [Mbps] and path loss [dB] are defined, rendered
respectively in red, orange, yellow, and green. Red areas may have adequate
connectivity for streaming high definition video, while the yellow areas are only
suited for web browsing.

4. DEUS
Deployment and Ease Use of wireless Services
The drawing tool is implemented in Adobe Flex 3. This has the following benefits:
• The tool is cross-platform. The Adobe Flash multimedia platform is well-
established on Windows and OS X.
• No software installation is required. The drawing tool can be used on any
computer with a current web browser and Adobe Flash installation.
• The Flex framework has an API for communicating with a remote server, such as
a SOAP (Simple Object Access Protocol)-based web service.
DEUS Proof of Concept implementation
Currently, the tool is able to calculate path loss and throughput for a set of access points
placed on a map of a ground plan, obtained in one of the three ways mentioned before. A
first version of the automatical access point placement feature is implemented as well.
Project partners
In cooperation with
IBBT research groups
UGent - IBCN http://www.ibcn.intec.ugent.be
UGent - WiCa http://www.wica.intec.ugent.be
UA - PATS http.www.pats.ua.ac.be
KU Leuven – DistriNet http.www.distrinet.cs.kuleuven.be
KU Leuven – CUO http://www.soc.kuleuven.be/com/mediac/cuo
UHasselt – EDM http://www.edm.uhasselt.be/