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The defense date of the thesis is 2014-08-04
The current date is 2019-03-22
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URN etd-0731114-165141 Statistics This thesis had been viewed 844 times. Download 5 times. Author Wei-chun Sun Author's Email Address No Public. Department Communication Engineering Year 2013 Semester 2 Degree Master Type of Document Master's Thesis Language zh-TW.Big5 Chinese Page Count 49 Title A LOW-COMPLEXITY PTS SCHEME FOR PAPR REDUCTION IN SC-FDMA SYSTEMS Keyword partial transmit sequences Single-carrier frequency division multiple acces peak-to-average power ratio peak-to-average power ratio Single-carrier frequency division multiple acces partial transmit sequences Abstract Single carrier frequency division multiple access (SC-FDMA) is used in the uplink of Long Term Evolution (LTE) systems because of the low peak-to-average power ratio (PAPR) of the transmitted signal. In SC-FDMA systems, a discrete Fourier transform (DFT) is added in front of OFDMA systems, so SC-FDMA systems are also called linear predictive coding systems.
SC-FDMA systems have a lower peak-to-average power ratio (PAPR) than OFDMA systems about 1 ~ 3 dB. A low PAPR means that a low power consumption in the transmission side, which can extend the battery life and improve the efficiency of the power amplifier for the mobile terminals. However, for the high order modulations such as 16-quadrature amplitude modulation (QAM) and 64-QAM, the PAPR of the SC-FDMA signals is still large.
Many methods have been proposed to reduce the PAPR for SC-FDMA systems. Among these methods, the partial transmit sequences (PTS) scheme can effectively reduce the PAPR of SC-FDMA systems without causing signal distortion. But the conventional PTS scheme needs high computational complexity in the optimization process to find the optimal candidate signals with the lowest PAPR value.
In this thesis, we propose a low-complexity hybrid PTS scheme for SC-FDMA systems. In the proposed hybrid PTS scheme, we use the combination of pseudo-random and interleaving subblock partition methods to divide the input data block into several subblocks evenly. Then, a set of cost functions is generated by using the sample powers of subblocks. The cost functions generated can be used to select samples for estimating the peak power of each candidate signal. Because only a part of samples are computed in the optimization process, the total computational complexity of the proposed PTS scheme is reduced. In addition, we use a low-complexity transformation matrix to multiply one of the subblocks to increase the number of candidate signals for improving the PAPR reduction performance of the proposed PTS scheme. The simulation results show that the proposed hybrid PTS scheme has a good PAPR reduction performance for SC-FDMA systems, but has much lower computational complexity than the conventional PTS method.
Advisor Committee Sheng-ju Ku - advisor
Files Date of Defense 2014-07-22 Date of Submission 2014-08-04