| Summary: | 碩士 === 大同大學 === 通訊工程研究所 === 98 === OFDM (Orthogonal Frequency Division Multiplexing) technique is a popular communication system, because the OFDM technique can be achieved high data rate transmission, robustness to the multipath fading and immunity to impulse interference. However, an OFDM signal have very high peak-to-average power ratio (PAPR) problem. The high peaks of an OFDM signal are distorted nonlinearly by the power amplifier (PA), because high peaks effects such as the in-band distortion and the out-of-band radiation due to the, and increase the bit error rate(BER).
In this paper, we propose method using combined selected mapping(SLM) and dummy sequence inserted (DSI) scheme, In the modified method we improve the energy dummy sequence inserted, when the dummy sequence insertion length is 4,lower 68.75% than the original method of using the number of IFFT and Can reduce the 1.5dB PAPR, when the dummy sequence insertion length is 8, lower 96.48% than the original method of using the number of IFFT and Can reduce the 3.2dB, and can keeping the similar orthogonal frequency division multiplexing (PAPR) reduction performance compared with the modified DSI scheme.
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