| dc.description.abstract | Multipath fading effect is a common problem of electromagnetic wave or signal
propagation. For WSN (Wireless Sensor Networks) system, the effect is able to degrade the system by contributing to the problem of packet rejection, packet loss and shortening the network lifetime. The existence and level of the effect is totally depend on the conditions of the communication system environment. To solve the problem of
the effect, a signal propagation study must be conducted in the environment where the
system will be implemented. The objectives of this research is to study the signal
propagation characteristics of WSN devices and the devices physical position that
influence signal propagation characteristics, to verify suitable analysis tools (Packet
Error Rate, average received power, standard deviation, goodness of fit χ² test and Rice
K ) for signal propagation study, to study the signal propagation of WSN devices in
aquaculture environments with focusing on multipath fading effect issue, to minimise
multipath fading effect by using the method of controlling time interval between
packets transmission and to study the feasibility of WSN system to be implemented in
aquaculture environments. The first experiment was conducted at an open outdoor area
(sports arena). The experiment was conducted by placing the nodes in different
positions (vertical, horizontal and low) at different distances (10 – 40 m) between
nodes. The result shows the vertical position has the best performance in all analysis.
The average received power curve is monotonic and it can be modeled by second order
of polynomial equation. From this equation, the maximum range of communication is
estimated at 70 m. The second experiment was conducted at an indoor aquaculture
environment (fish hatchery). In this environment, the multipath fading effect is found at
low level where the standard deviation analysis shows Tank 3 has high variation of data
and the Rice K analysis shows the direct component of Tank 9 is not monotone. After
sending packets at 100 ms, the effect has been minimised with the variation of data is
become low for Tank 3 and the direct component of Tank 12 is become monotone. The
third experiment was conducted at an outdoor aquaculture environment (fish pond).
This experiment found that the effect at this environment is at high level, where the
PER value for side D is more than 1%. After sending packets at 50 ms, the effect can be
minimised with the PER value of Side D become less than 1%. This research concludes
that the multipath fading effect is exist in aquaculture environment. By using
combination of PER, average RSSI, standard deviation, χ² test and Rice K analysis tools
is able to analyse the multipath fading effect. This effect can be minimised by
controlling time interval between packets transmission. From this research is obtained
that WSN is feasible to operate in aquaculture environment. | en_US |
