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Minimizing Peak-to-Average Power Ratio in an Orthogonal Frequency Division Multiplex System

Posted on:2015-03-21Degree:Ph.DType:Dissertation
University:The University of Wisconsin - MadisonCandidate:Bunnag, JittapatFull Text:PDF
GTID:1478390017498927Subject:Engineering
Abstract/Summary:
Orthogonal frequency division multiplexing (OFDM) is a popular standard in wireless communication for its enabling high throughput data transfer. However, the OFDM signal usually has a high peak-to-average power ratio (PAPR), which requires a wide-dynamic-range, powerconsuming amplifier. Whenever the signal peak is greater than the amplifier linear region, the signal is distorted. This distortion generates interference in both in-band and out-of-band spectrum. The effect of in-band interference becomes apparent at medium to high SNR levels and reduces system performance gains as the SNR increases.;We endeavor to improve the system BER by minimizing the signal peak using signal scrambling techniques. These techniques effectively reduce the signal peak and enhance system performance when the receiver is able to correctly decode the scrambling information. This information is a weakness of existing techniques because a resource is needed to transport it, and its corruption dramatically undermines system performance.;We propose a novel scheme that utilizes resources allotted for channel estimation and does not need to transmit explicit scrambling information. Therefore, our technique improves over the existing ones in the same category. In addition, we propose some procedures to alleviate scrambling information corruption and show discernible advancements.;We study the trade-off between PAPR reduction and channel estimation when they have to compete for the same resource. We suggest doing PAPR reduction only when the receiver can obtain a good channel estimate to ensure favorable system performance.
Keywords/Search Tags:System, PAPR, Peak
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