| Summary: | 碩士 === 國立中央大學 === 通訊工程學系 === 104 === Orthogonal Frequency Division Multiplexing (OFDM) has been
widely used in communication fields. One of the major drawbacks of
OFDM is high peak-to-average power ratio (PAPR) for the transmitted
signals. Therefore, the issue about how to remedy the PAPR in an OFDM
system is important. Nowadays, many techniques have been developed
to reduce the problem of high PAPR. Partial Transmit Sequence (PTS)
is one of the attractive techniques to reduce the PAPR, but PTS requires
an exhaustive search for all combinations of allowed phase factors such
that the computational complexity is quite high. The sub-optimal algo-
rithms that combine the PTS technique and intelligent algorithms have
been frequently discussed in the past few years. It can effectively reduce
PAPR and significantly decrease computational complexity. As a result,
iiithis type of sub-optimal algorithms become a subject that draws a lot of
interest.
However, there is still some performance gap between the sub-optimal
algorithms and the traditional PTS solutions. In this thesis, we propose a
new method based on the intelligent algorithms which reduces the sim-
ilarity during searching for the phase factors for PTS in order to avoid
the solutions falling in local minimum. The proposed method can ef-
fectively reduce PAPR though it may increase computational complexity
more than the original intelligent algorithms.
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