Abstract
The demand for wireless access to the internet is constantly increasing and the applications
such as social media, gaming and video require a high bandwidth connections. Mobile technologies
are becoming more affordable and accessible. Existing telecommunications systems
can be improved to ensure that it is sustainable for future generations.
Orthogonal Frequency Division Multiplexing (OFDM) is a good candidate which is already
used widely in wireless applications. It is robust against many of the multipath effects
commonly encountered in wireless channels. It also makes efficient use of the limited radio
spectrum.
Certain parameters of the OFDM system have been investigated and recommendations
on the optimal parameters are made in order to achieve the best bit error rate (BER) performance.
These investigations have been conducted by designing a comprehensive and
configurable simulation of the OFDM system, including an adapted modulator and demodulator
and an accurate channel model.
The guard interval is an important design consideration as it counters Inter Symbol Interference
(ISI). The optimal length of the guard interval should be less than 25% of the
total symbol length. As shorter guard interval results in more usable bandwidth. The choice
of quadrature amplitude modulation (QAM) scheme to use is also an important one and
the optimal design depends on the throughput requirements of the system. The number of
subcarriers depends on the available bandwidth and the subcarrier spacing....
M.Ing. (Electrical Engineering)