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Adaptive OFDM modulation techniques over fading channel for wireless communication systems with an 80 MHz bandwidth
(2010-05-05)
Lakanchanh, Donekeo
;
Noppanakeepong, Suthichai
;
Yoshizawa, Shingo
;
Miyanaga, Yoshikazu
The orthogonal frequency division multiplexing (OFDM) is one of the promising technologies to improve the spectral efficiency, enhance system capacity and mitigate inter-symbol interference in the wireless communication system. In this paper, we aim at the study on adaptive modulation and coding technologies for wireless system over frequency selective fading channel. This adaptive allocation algorithm assigns the sub-carriers. We are applied adaptive modulation technique to each sub-carrier to keep required BER and PER performance. The system chooses modulation among BPSK, QPSK, 16QAM and 64QAM which the estimated SNR of the sub-carrier inhabits. Adaptive modulation can improve communication performance under small SNR. The computer simulation result shows the BER, PER and Throughput performance can be improved under 30 dB of SNR region. ©2010 IEEE.
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New hybrid of PTS-CAPPR methods using GA for PAPR reduction in OFDM systems
(2009-12-01)
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 coded side information (SI) technique design by genetic algorithm(GA). These methods are used in an Orthogonal Frequency Division Multiplexing (OFDM) system. The OFDM employs orthogonal subcarriers for data modulation. These sub-carriers unexpectedly present a large peak to average power ratio (PAPR) in some cases. A proposed reduction method consists of these two methods and realizes both advantages at the same time. In order to obtain 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 designed by GA, 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. ©2009 IEEE.
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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 PTS method with coded side information technique for PAPR reduction in OFDM systems
(2008-12-01)
Pradabpet, Chusit
;
Yoshizawa, Shingo
;
Miyanaga, Yoshikazu
;
Chivapreecha, Sorawat
;
Dejhan, Kobchai
In this paper, we propose a new PAPR reduction by using a partial transmit sequences (PTS) method with coded side information (SI) technique. 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 partitioned into disjoint sub-block of PTS. If number of sub-block increases, high efficiency of PAPR reduction can be obtained. However, a quite large calculation cost must be demanded and thus it is impossible to obtain the optimum PTS. In the proposed method, we introduce a coded side information technique assuming the pseudo-optimum condition into the PTS. The total calculation cost becomes drastically reduced and side information bits for recovering original data in demodulation. In simulation results, the proposed method demonstrated the improvement of PAPR and bit error rate (BER) performance. © 2008 IEEE.
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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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