Abstract
AbstractOrthogonal frequency division multiplexing (OFDM) systems support high data rate wireless transmission using orthogonal frequency channels, and can effectively take care of the inter-symbol interference induced by multipath propagation over radio channels. One of the major drawbacks associated with OFDM is the high peak-to-average power ratio (PAPR), which can result in significant distortion when the signal is transmitted through a nonlinear device, such as a transmitter power amplifier.In this thesis, some main PAPR reduction methods are reviewed, including the selective mapping (SLM) approach and the partial transmit sequences (PTS) approach. Although the SLM and PTS techniques are very efficient in reducing PAPR, they would involve high system complexity, where input data sequence and several parallel IFFTs are required. To alleviate this problem, we propose an IFFT conversion method that can generate a set of different IFFTs from a computed IFFT. Since the proposed IFFT conversion method doest not involve any multiplication, it has much lower complexity than the IFFT compotation. With this IFFT conversion method, the complexity of the SLM and PTS techniques can be reduced significantly.