Title page for etd-0823110-141203


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URN etd-0823110-141203
Author Sen-Hung Wang
Author's Email Address senhung@gmail.com
Statistics This thesis had been viewed 5582 times. Download 6 times.
Department Electrical Engineering
Year 2009
Semester 2
Degree Ph.D.
Type of Document
Language English
Title Low-Complexity PAPR Reduction Schemes for Multi-Carrier Systems
Date of Defense 2010-07-30
Page Count 127
Keyword
  • Peak-to-Average Power Ratio (PAPR)
  • Selected Mapping (SLM)
  • Space-Frequency Block Coding (SFBC)
  • Multiple-Input Multiple-Output (MIMO)
  • Orthogonal Frequency Division Multiple Access (OFDMA)
  • Conversion Vectors
  • Perfect Sequence
  • Orthogonal Frequency Division Multiplexing (OFDM)
  • Abstract Selected mapping (SLM) schemes are commonly employed to reduce the peak-to-average power ratio (PAPR) in orthogonal frequency division multiplexing (OFDM) systems. It has been shown that the computational complexity of the traditional SLM scheme can be substantially reduced by adopting conversion vectors obtained by using the inverse fast Fourier transform (IFFT) of the phase rotation vectors in place of the conventional IFFT operations. To ensure that the elements of these phase rotation vectors have an equal magnitude, conversion vectors should have the form of a perfect sequence. This study firstly presents three novel classes of perfect sequence, each of which comprises certain base vectors and their cyclically shifted versions. Three novel low-complexity SLM schemes are then proposed based upon the unique structures of these perfect sequences. It is shown that while the PAPR reduction performances of the proposed schemes are marginally poorer than that of the traditional SLM scheme, the three schemes achieve a substantially lower computational complexity. Since the three proposed PAPR reduction schemes cannot be utilized in the orthogonal frequency division multiple access (OFDMA) system. A low-complexity scheme for PAPR reduction in OFDMA uplink systems using either an interleaved or a sub-band sub-carrier assignment strategy is also proposed in the second part of this study. The proposed scheme requires just one IFFT operation. The PAPR reduction performance of the proposed scheme is only marginally poorer than that of the traditional SLM scheme. However, the proposed schemes have significantly lower computational complexities. Besides, multiple-input multiple-output (MIMO) OFDM systems with space-frequency block coding (SFBC) are well-known for their robust performance in time selective fading channels. However, SFBC MIMO-OFDM systems have a high computational complexity since the number of IFFTs required scales in direct proportion to the number of antennas at the transmitter. Furthermore, SFBC MIMO-OFDM systems have a high PAPR. Accordingly, a low-complexity PAPR reduction scheme for SFBC MIMO OFDM systems with the Alamouti encoding scheme is proposed in this study. Extending this scheme obtains two low-complexity transmitter architectures for SFBC MIMO-OFDM systems with a general encoding matrix and an arbitrary number of transmitter antennas. The proposed schemes achieve a significant reduction in computational complexity by fully exploiting the time-domain signal properties of the transmitted signal. In addition, a PAPR reduction scheme is presented based on the proposed transmitter schemes. It is shown that the PAPR reduction performance of the proposed scheme is almost as good as that of the traditional SLM scheme, but is achieved with a substantially lower computational complexity.
    Advisory Committee
  • Chin-Liang Wang - chair
  • Yu-Chao Tang - co-chair
  • Ding-Bing Lin - co-chair
  • Chao-Kai Wen - co-chair
  • Chua-Chin Wang - co-chair
  • Tsang-Yi Wang - co-chair
  • Yu T. Su - co-chair
  • Char-Dir Chung - co-chair
  • Chih-Peng Li - advisor
  • Files
  • etd-0823110-141203.pdf
  • indicate in-campus access in a year and off_campus not accessible
    Date of Submission 2010-08-23

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