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New papr reduction in ofdm systems by hybrid algorithm of pts and appr methods
(2009-12-01)
Pradabpet, C.
;
Yoshizawa, S.
;
Miyanaga, Y.
;
Dejhan, K.
In this paper, we propose a new peak to average power ratio (PAPR) reduction technique by a hybrid algorithm based on a partial transmit sequence (PTS) and adaptive peak power reduction (APPR) methods. This technique is used in a system based on orthogonal frequency division multiplexing (OFDM OFDM has orthogonally modulated sub-carriers which unexpectedly give large PAPR and tends to reduce the power efficiency of a RF amplifier. To reduce PAPR, the sequence of input data is rearranged by PTS for the reduction of PAPR and then fed to APPR process in the proposed system. The APPR method controls the peak level of the modulation signal by an adaptive algorithm. It reduces modulation signals over a predefined range. A proposed reduction method consists of these two methods and realizes both advantages at the same time. In simulation results, the proposed method shows the improvement on PAPR, PSD, and also the high performance on bit error rate of an OFDM system.
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Searching phase optimize in PTS-APPR method by GA for PAPR reduction in OFDM-WLAN systems
(2009-11-12)
Pradabpet, C.
;
Yoshizawa, S.
;
Miyanaga, Y.
;
Dejhan, K.
In this paper, we propose a new PAPR reduction using the hybrid of a partial transmit sequences (PTS) and an adaptive peak power reduction (APPR) methods with 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. 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 genetic algorithm, the total calculation cost becomes drastically reduced. The parameter for simulation used standard WLAN in IEEE 802.11a system. 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. © 2009 IEEE.
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An efficient filter structure for multiplierless sobel edge detection
(2009-11-12)
Pradabpet, C.
;
Ravinu, N.
;
Chivapreecha, S.
;
Knobnob, B.
;
Dejhan, K.
This paper presents a multiplierless Sobel edge detection filter structure based on the gradient of Gaussian lowpass filter concept. This concept is same as the idea that used for evaluation of Sobel edge detection kernels. The proposed Sobel edge detection filter structure consists of 4 sets of the so-called lowpass-type 2nd order 1-D DPF (Discrete Pascal Filter) and the filter structure does not need any multipliers, only 14 adders are needed for realization. Consequently, the high efficiency multiplierless Sobel edge detector can be achieved. © 2009 IEEE.
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A new PAPR reduction technique for OFDM-WLAN in 802.11a systems
(2008-12-24)
Pradabpet, C.
;
Eupree, K.
;
Chivapreecha, S.
;
Dejhan, K.
In this paper, we proposed a new PAPR reduction technique using selective mapping (SLM) cascade with adaptive peak power reduction (APPR) methods. This technique is used in a system based on Orthogonal Frequency Division Multiplexing (OFDM). OFDM has many orthogonally modulated sub-carriers which unexpectedly produce high peak to average power ratio (PAPR). The high PAPR will occasionally reach the amplifier saturation region and therefore result in signal distortion, which causes bit error rate (BER) degradation. The proposed method, a sequence of input data is rearranged by SLM for the reduction of PAPR and then fed into the APPR process in the proposed system. The APPR method controls the peak levels of the modulation signal by an adaptive algorithm. It reduces modulation signals over a predefined range. The parameter for simulation used standard WLAN in IEEE 802.11a system. In simulation results, the proposed method shows the improvement on PAPR, power spectrum density(PSD) and high performance BER compared with conventional APPR. © 2008 IEEE.
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PAPR reduction in OFDM systems using SLM cascade with APPR methods
(2008-10-06)
Eupree, K.
;
Chivapreecha, S.
;
Dejhan, K.
;
Pradabpet, C.
In this paper, we proposed a new PAPR reduction technique using selective mapping (SLM) cascade with adaptive peak power reduction (APPR) methods. This technique is used in a system based on Orthogonal Frequency Division Multiplexing (OFDM). OFDM has many orthogonally modulated subcarriers which unexpectedly produce a peak to average power ratio (PAPR) and tend to reduce the power efficiency of a RF amplifier. A sequence of input data is rearranged by SLM for the reduction of PAPR and then fed into the APPR process in the proposed system. The APPR method controls the peak levels of the modulation signal by an adaptive algorithm. It reduces modulation signals over a predefined range. In simulation results, the proposed method has shown better PAPR reduction compared to the SLM and the APPR. ©2008 IEEE.
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A new PAPR reduction in OFDM-WLAN systems by hybrid algorithm of PTS and APPR methods
(2007-12-01)
Pradabpet, C.
;
Yoshizawa, S.
;
Miyanaga, Y.
;
Dejhan, K.
In this paper, we propose a new PAPR reduction technique by a hybrid algorithm based on a partial transmit sequence (PTS) and adaptive peak power reduction (APPR) methods. 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. A sequence of input data is rearranged by PTS for the reduction of PAPR and then fed to APPR process in the proposed system. The APPR method controls the peak level of the modulation signal by an adaptive algorithm. It reduces modulation signals over a predefined range. A proposed reduction method consists of these two methods and realizes both advantages at the same time. In simulation results, the proposed method shows the improvement on PAPR and also the high performance on bit error rate performance of an OFDM system. ©2007 IEEE.
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Design and implementation of biquad digital filter
(2003-01-01)
Pradabpet, C.
;
Yimman, S.
;
Hinjit, W.
;
Chivapreecha, S.
;
Dejhan, K.
This paper presents a design and implementation of biquad digital filter based on poles-zeros placement on a unit circle of z-plane. The proposed digital filter can be given three frequency-responses as lowpass filter (LPF), highpass filter (HPF) and bandpass filter (BPF) at the same time. In the design process the Matlab program was used, for real world implementation by using TMS320C31 DSP board. The experimental results shown by the dynamic signal analyzer to indicate that the obtained frequency responses give the same results as design specifications.

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