| Summary: | 碩士 === 國立臺北科技大學 === 電子工程系研究所 === 104 === In wireless communication systems, orthogonal frequency division multiplexing (OFDM) system utilizes mutually orthogonal subcarriers with various frequencies to transmit data. It has the advantage of high spectral efficiency. Nevertheless, the disadvantage of this system is that its receiver is sensitive to frame and frequency synchronization signals. Furthermore, the time delay generated from multipath transmission might lead to the misjudgment of the starting point of frame signals , which could affect the accuracy of frame synchronization and increase the error rate of demodulation signal. As a result, this thesis focuses on frame non-synchronization and makes proposals for improvement.
In order to solve the problem of time delay generated from multipath transmission, this thesis presents a unitary preamble signal to do synchronous estimation. In addition, it is combined with sliding window and peak search algorithms to do frame estimation and correction so as to improve the success rate of frame synchronization, mean of timing offset and reduce mean square error. Simulation results indicate that the proposed method can actually enhance the estimation performance of frame synchronization.
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