9002

8347

كارشناسي ارشد

مخابرات سيستم

اصفهان: دانشگاه صنعتي اصفهان، دانشكده برق و كامپيوتر

1392

دوازده،98ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

محمدجواد اميدي، مجتبي بهشتي

18/3/93

عليمحمد دوست حسيني، احسان يزديان

مهندسي برق و كامپيوتر

ID8347

99 PAPR Reduction in MIMO OFDM Systems Using Spatial and Temporal Processing Bashir Reza Karimi b karimi@ec iut ac ir Date of Submission 2013 28 10 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language English Supervisor Mohammad Javad Omidi omidi@cc iut ac ir Mojtaba Beheshti behesht@cc iut ac irAbstract Modern digital communication systems take advantage of the combined application of orthogonalfrequency division multiplexing OFDM and multiple input multiple output MIMO systems oftendenoted as MIMO OFDM OFDM modulation combats frequency selective fading effectively by dividing awideband frequency selective fading channel into parallel narrowband at fading subchannels MIMOmethods can improve the error performance signal quality and system capacity Therefore thecombination of MIMO technology and OFDM is a viable solution for future wireless communicationsystems The time domain MIMO OFDM signal is a summation of several orthogonal waveforms So largepeaks which are much higher than the average of the signal may happen This phenomenon is called highpeak to average power ratio PAPR which is a major drawback of MIMO OFDM systems at thetransmitter side The high PAPR increases the complexity of digital to analog converters DACs Also itcan cause non linear distortion due to non linear devices such as high power amplifiers HPAs The non linear distortion introduces spectral spreading inter modulation and changes in the signal constellation PAPR reduction schemes based on signal modification have been proposed to deal with the PAPR problem Various PAPR reduction methods for single input single output SISO OFDM systems have beenproposed Recently several articles addressed the PAPR reduction for MIMO OFDM systems In thisthesis three new methods have been proposed for PAPR reduction in MIMO OFDM systems In theproposed methods the OFDM block at each transmit antenna is partitioned into disjoint subblocks Thesefrequency domain subblocks are transformed to the time domain by IFFT operation Then spatial andtemporal processing are applied to the time domain subblocks across all transmit antennas Finally acandidate sequence with the best PAPR statistics is chosen for each transmit antenna Simulation resultsshow that the proposed methods substantially outperform the conventional PAPR reduction schemes Also the proposed methods induce lower complexity than that of the conventional schemes Keywords MIMO OFDM Peak to average power ratio Spatial and temporal processing

محمدجواد اميدي، مجتبي بهشتي

عليمحمد دوست حسيني، احسان يزديان