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Author: search.filters.author.Miyanaga, YoshikazuSubject: search.filters.subject.OFDM

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    Histogram compensation to improve blind modulation detection in adaptive OFDM
    (2009-12-01)
    Lakanchanh, Donekeo
    ;
    Yoshizawa, Shingo
    ;
    Noppanakeepong, Suthichai
    ;
    Miyanaga, Yoshikazu
    This paper proposes a blind modulation detection technique for adaptive orthogonal frequency division multiplexing (Adaptive OFDM) communications. Adaptive modulations are applied to improve communication performance in OFDM over complicated multi-path fading channels. This paper proposes a new method which reduces detection errors in blind modulation and improves communication throughput in adaptive OFDM systems. The new proposed is based on statistical methods using a combination of distance histogram and phase histogram methods. It can improve communication performance and increases a data rate by not sending side information about modulation modes. The proposed method has showed better blind detection performance at lower SNR regions than the previous method. ©2009 IEEE.
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    New PAPR reduction in an OFDM system using hybrid of PTS-CAPPR methods with GA coded side information technique
    (2009-01-01)
    Pradabpet, Chusit
    ;
    Yoshizawa, Shingo
    ;
    Miyanaga, Yoshikazu
    ;
    Dejhan, Kobchai
    In this paper, we propose a new PAPR reduction by using the hybrid of partial transmit sequences (PTS) and cascade adaptive peak power reduction (CAPPR) methods with side information (SI) technique coded by genetic algorithm (GA). These methods are used in an Orthogonal Frequency Division Multiplexing (OFDM) system. The OFDM employs orthogonal sub-carriers for data modulation. These sub-carriers unexpectedly present a large peak to average power ratio (PAPR) in some cases. A proposed reduction method realizes both the advantages of PTS and CAPPR at the same time. In order to obtain the optimum condition on PTS for PAPR reduction, a quite large calculation cost is demanded and thus it is impossible to obtain the optimum PTS in a short time. In the proposed method, by using the pseudo-optimum condition based on a GA coded SI technique, the total calculation cost becomes drastically reduced. In simulation results, the proposed method shows the improvement on PAPR and also reveals the high performance on bit error rate (BER) of an OFDM system. Copyright © 2009 The Institute of Electronics, Information and Communication Engineers.
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    New PAPR reduction in OFDM system using hybrid of PTS-APPR methods with coded side information technique
    (2008-01-01)
    Pradabpet, Chusit
    ;
    Yoshizawa, Shingo
    ;
    Miyanaga, Yoshikazu
    ;
    Dejhantt, Kobchai
    SUMMARY In this paper, we propose a new PAPR reduction by using the hybrid of a partial transmit sequences (PTS) and an adaptive peak power reduction (APPR) methods with coded side information (SI) technique. These methods are used in an Orthogonal Frequency Divi cion Multiplexing (OFDM) system. The OFDM employs orthogonal sub-carriers for data modulation. These sub-carriers unexpectedly present a large Peak to Average Power Ratio (PAPR) in some cases. In order to reduce PAPR, the sequence of input data is rearranged by PTS. The APPR method is also used to controls the peak level of modulation signals by an adaptive algorithm. A proposed reduction method consists of these two methods and realizes both advantages at the same time. In order to make the optimum condition on PTS for PAPR reduction, a quite large calculation cost must be demanded and thus it is impossible to obtain the optimum PTS. In the proposed method, by using the pseudo-optimum condition with a coded SI technique, the total calculation cost becomes drastically reduced. In simulation results, the proposed method shows the improvement on PAPR and also reveals the high performance on bit error rate (BER) of an OFDM system. Copyright © 2008 The Institute of Electronics.
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    PAPR reduction in OFDM systems by hybrid algorithm based on the PTS and APPR methods
    (2007-12-01)
    Pradabpet, Chusit
    ;
    Miyanaga, Yoshikazu
    ;
    Dejhan, Kobchai
    In this report, we propose a new PAPR reduction technique by a hybrid algorithm based on a partial transmit sequence (PTS) and adaptive peak power reduction (APPR) method. This technique is used in a system based on Orthogonal Frequency Division Multiplexing (OFDM). OFDM has many orthogonally modulated subcarriers which unexpectedly give a large peak to average power ratio (PAPR) and tends to reduce the power efficiency of a RF amplifier. The input data using the PTS method, a sequence of input data is rearranged for the reduction of PAPR and fed to APPR process. The APPR method controls the peak level of the modulation signal based on an adaptive algorithm which reduces modulation signals over a predefined range. A proposed reduction method consists of these two methods and realizes bolt advantages at the same time. As simulation results, the proposed method shows the improvement on PAPR and also the bit error rate performance of an OFDM system.