Indoor Communication, 802.11g with Multi-Wall Model (COST
231)
The network planning of a local area network in an indoor scenario is investigated.
The model is a multi-floor building. The multi-wall model (COST 231) method is
used.
Sites and Antennas
There are five antenna sites in different locations in the building. The antennas are
installed at a height of 2.5 m. The omnidirectional antennas used in this model are
working on different frequencies to minimize interference. The carrier frequencies
are around 5.2 GHz.
Air Interface
The wireless local area network (WLAN) air interface is defined by an 802.11a
wireless standard (.wst) file. OFDM/SOFDMA (orthogonal
frequency-division multiplexing) is selected for multiple access. It uses time
division duplex (TDD) for switching between uplink and downlink. In this example,
only downlink carriers are defined since the uplink and downlink are separated in
time. The adaptive switching method is used depending on the traffic load.
Tip: Click Project > Edit Project Parameter and click the Air Interface tab to view
the carriers and transmission modes.
Computational Method
The computational method used for this model is the multi-wall model (COST 231).
Tip: Click Project > Edit Project Parameter and click the Computation tab to change
the model.
This
propagation model takes into account various material properties of internal walls,
special walls, doors, floors, and ceilings to predict the coverage in the building.
This method calculates the path loss as the sum of distance-dependent free-space
loss and losses introduced by the walls and floors penetrated by the direct path.
Signals are assumed to travel along straight paths, which is good for computational
speed, but diffractions and multipath are not considered.
Tip: Click Project > Edit Project Parameter and click the Computation tab to change
the model.
Results
Propagation results show the power received from each transmitting antenna at every
location.
The network simulation also calculates, among other quantities, the minimum required
transmitter power, maximum achievable received signal strength, and the SNIR for all
modulation and coding schemes used in this model. One result of interest is the
maximum data rate, see Figure 1.
The white pixels are an indication that the received power is too low for
communication with this standard or that the interference (SNIR) is too high for
communication (but that is not the case here since all antennas employ a different
carrier frequency).
