基于ieee 802.16a协议的ofdm系统降低峰均功率比的研究the ofdm system based on ieee 802.16 a deal to reduce peak power than research.docx

南京|1I|{『U学院{Ⅲ!}学位论文 Abstract
Abstract
Orthogonal Frequency Division Multiplexing (OFDM) techn0109y is a modulation technology which can decrease the t of the noise and interferences ,it has much more adV觚tages such as hi曲er band e豫ciency and less impact of ISI(Inter Symbol Inference). HoweV er,the high PAPR(Peak-to-A=verage Power Ratio)is the main出awback of me oFDM system. OFDM transmitters therefbre require linear amplifiers with wide dynamic range. Linear amplifiers are expensiVe and amplmer non-1inearity will cause intermodulation products resul“ng in unwanted out—of_band power and increased interfjrence.
This dissertation firstly desc“bes the protocol models of and the theories of OFDM technology,as well as the nonlinear distortion to OFDM signals caused by high power ampliner. This dissenation points out the problem of high PApR, introduces two kinds of methods of reducing PAPR, those are
signal-nondistortion method and signal—predistortion of PAPR and BER of the system are improved partiaI transmit sequence(PTS) schemes is introduced and its PAPR reduction plexities are analized. Furthermore, the sign乱-predistortjon methods are introduced and an panding transform scheme is proposed ajld analyzed.
parisons of these methods show that,in signal一nondistortion memods, the iteratiVe—shiRing linear searching PTS with more phases and plexity call ensure the lo、ver BER of the svstem and the efrective reduction of the PAPR as well. 0n the other halld,in signal-predistortion metllods,the panding
transform plexity is alsO an ef!tive method to reduce PAPR.
Finall y’we s啪marize the whole、vork ofthis dissertation.
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