• Title, Summary, Keyword: PAPR

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PAPR Reduction Method Using SLM-based WHT and DSI (SLM 기반 Walsh Hadamard 변환 및 DSI 기법을 이용한 PAPR 저감 기법)

  • Kim Sang-Woo;Kim Namil;Ryu Heung-Gyoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.11
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    • pp.1147-1154
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    • 2005
  • In this paper, we propose some PAPR(Peak to Average Power Ratio) reduction methods using WHT(Walsh Hadamard Transform) to reduce high PAPR generated in OFDM system because of multi carrier modulation. These proposed methods are the methods which has additional PAPR reduction performance without a loss of bandwidth efficiency and a large increment of calculation complexity than common PAPR reduction methods by combining the WHT with some common methods. In this paper, we propose two PAPR reduction methods made by combining a SLM(Selective Mapping) and DSI(Dummy Sequence Insertion) with a WHT. From simulation result, we can find that the PAPR reduction methods using a WHT can get about 1 dB additional PAPR reduction performance than common PAPR reduction methods; they are SLM and DSI. And, because our proposed methods have not only PAPR reduction effect, but also frequency diversity effect, more stabile data transmission is possible in nonlinear HPA and multipath fading channel.

Peformance Analysis of a Pre-Scrambling Scheme for Reducing the PAPR in OFDM Systems (OFDM 시스템에서 PAPR의 감소를 위한 사전-스크램블링 기법의 성능분석)

  • 최광돈;김시철;박상규
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.29 no.5A
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    • pp.521-526
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    • 2004
  • OFDM is a very attractive technique for achieving high-bit-rate data transmission and high spectrum efficiency. However, one of disadvantages of OFDM signal is the high PAPR characteristic when multi-carriers are added up coherently. In this Paper, we propose-scrambling scheme using correlator for PAPR reduction and reducing the amount of PAPR calculations. The simulation results show that this scheme has less computational complexity and reasonable PAPR reduction capability compared to PTS technique.

PAPR Improvement of OFDM-CQAM System through Optimum Position based Impulse Insertion in Frequency Domain (주파수영역 최적위치기반 임펄스 삽입에 따른 OFDM-CQAM 시스템의 PAPR 개선)

  • Kwak, Jae-min
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.597-599
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    • 2019
  • When frequency domain high amplitude impulse is inserted before IFFT in OFDM transmitter, the PAPR of OFDM signal in tme domain can be effectively reduced. In this paper, the degree of PAPR improvement of OFDM communication system with CQAM subcarrier modulation is analysed by adopting impulse insertion technique before IFFT of transmitter. Furthermore, it is verified that additional PAPR performance improvement can be obtained by finding optimum position of impulse insertion for maximizing PAPR reduction.

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Design and Performance Evaluation of an Advanced CI/OFDM System for the Reduction of PAPR and ICI (PAPR과 ICI의 동시 저감을 위한 개선형 CI/OFDM 시스템 설계와 성능 평가)

  • Ryu, Heung-Gyoon
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.6A
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    • pp.583-591
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    • 2008
  • OFDM (orthogonal frequency division multiplexing) has serious problem of high PAPR (peak-to-average power ratio). Recently, CI/OFDM (carrier interferometry OFDM) system has been proposed for the low PAPR. However, CI/OFDM system shows another problem of ICI because of phase offset mismatch due to the phase noise. In this paper, to simultaneously reduce the PAPR and ICI effects, we propose an A-CI/OFDM (advanced-CT/OFDM). This method improves the BER performance by use of the margin of phase offset at CI codes. Propose system to reduce the effect the phase noise, even though it shows a little bit higher PAPR than conventional CI/OFDM, so we apply the PTS among the PAPR reduction techniques to proposed system to mitigate this problem. Therefore, it improves the total BER performance because the proposed method can decrease the effect of phase noise and get the gain in PAPR reduction performance. From the simulation results, we can show the performance comparison between the conventional OFDM, CI/OFDM and A-CI/OFDM.

PAPR Improvement of OFDM-CQAM System Through Optimum Position Impulse Insertion Scheme in Frequency Domain (주파수영역 최적 위치 임펄스 삽입기법에 의한 OFDM-CQAM 시스템의 PAPR 개선)

  • Kwak, Jae-Min
    • Journal of Advanced Navigation Technology
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    • v.23 no.3
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    • pp.258-263
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    • 2019
  • OFDM is popular digital communication method due to its immunity to multipath fading and capability of high speed data transmission, but it has disadvantage of high PAPR in transmission signal when many subcarrier modulated signal are added to the same phase. When frequency domain high amplitude impulse is inserted before IFFT in OFDM transmitter, the PAPR of OFDM signal in tme domain can be effectively reduced. In this paper, the degree of PAPR improvement of OFDM communication system with CQAM subcarrier modulation is analysed by adopting impulse insertion technique before IFFT of transmitter. Furthermore, it is verified that additional PAPR performance improvement can be obtained by finding optimum position of impulse insertion for maximizing PAPR reduction. Through computer simulation, the degree of PAPR improvement according to amplitude and position of inserted impulse is superior to conventional technique in OFDM-CQAM system.

Adaptive P-SLM Method with New Phase Sequence for PAPR Reduction of MIMO-OFDM Systems (MIMO-OFDM 시스템의 PAPR 감소를 위한 새로운 위상시퀀스의 적응형 P-SLM기법)

  • Yoo, Eun-Ji;Byun, Youn-Shik
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.36 no.3C
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    • pp.149-156
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    • 2011
  • MIMO-OFDM(Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing) has been spotlighted as a solution of high-quality service for next generation's wireless communications. However, like OFDM, one of main problems of MIMO-OFDM is the high PAPR(Peak-to-Average Power Ratio). In this paper, an adaptive P-SLM(Partitioned-SeLetive Mapping) based on new phase sequence is proposed to reduce PAPR. The proposed method has better performance and lower complexity than conventional method due to the use of periodic multiplication and adaptability by fixed critical PAPR value. Simulation results show that the proposed method has better performance and lower complexity than conventional method.

A Study on PAPR Reduction and Compensation for In-Band Distortion in OFDM Systems (OFDM 시스템에서 PAPR의 감소와 대역 내 왜곡 보정에 관한 연구)

  • Kim, Wan-Tae;Yoo, Sun-Yong;Cho, Sung-Jun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.5
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    • pp.912-920
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    • 2008
  • OFDM (Orthogonal Frequency Division Multiplexing) system is robust to frequency selective fading and narrowband interference in high-speed data communications. However, an OFDM signal consists of a number of independently modulated subcarriers, which can give a large PAPR (Peak-to-Average Power Ratio) when added up coherently. In this paper, we apply clipping and filtering to solve the PAPR problem and compensate the inband compensation using calculated EVM (Error Vector Magnitude). The proposed method can reduce the PAPR and inband distortion. From the results, we analyze the PAPR reducing efficiency and EVM, BER performance of proposed algorithm in the wireless communication system.

PAPR Reduction and BER Analysis of the OFDM System Using the TR and DCT Transform (톤 예약 기법과 DCT 변환을 이용한 OFDM 시스템의 PAPR 저감과 BER 분석)

  • Byeon, Heui-Seop;Shinn, Byung-Cheol;Ahn, Do-Seob
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.17 no.10
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    • pp.976-984
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    • 2006
  • OFDM system is very useful for the high speed communication system. However, OFDM system has a serious problem of high PAPR that results from the so many subcarriers in the same phase. This OFDM signal is distorted through the nonlinear HPA(High Power Amplifier). Tone reservation method is to insert tone signal in several types to reduce the PAPR after iterating this process by changing the tone signal. Also discrete cosine transform(DCT) can reduces the PAPR as multiplying the cosine value to change the angle and mix up with the data. In the paper, the combination of the TR method and DCT method is newly proposed for more effective reduction of the PAPR. Simulation results show that the proposed method outperforms the conventional simple TR method and DCT method with respect to the PAPR reduction and BER performance.

A PAPR Reduction Method Using the ACE(Active Constellation Extension) in the OFDM Communication System (OFDM 통신 시스템에서 능동 성상도 확장을 이용한 PAPR 감소 기법)

  • Kang Byoung-Moo;Kim Sang-Woo;Ryu Heung-Gyoon
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.16 no.6
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    • pp.586-593
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    • 2005
  • It is very important to reduce the PAPR(Peak to Average Power Ratio) in the OFDM(Orthogonal Frequency Division Multiplexing) communication system. We propose an ACE(Active Constellation Extension) method that does not require the side information unlike the conventional PTS and SLM method. This ACE method is to clip the OFDM signal for the PAPR reduction. Then, the basic constellation actively moves into the higher level of M-QAM for the constellation extension due to the clipping. The already existing M-QAM system can be available so that it can be easily realized. So, we can get the target PAPR by the extension of the constellation level. In this paper, we can find the PAPR reduction of 4 dB by the 16-QAM extension, and can achieve the target PAPR by the 64-QAM ACE(Active Constellation Extension).

PAPR Reduction Scheme Using Selective Mapping in GFDM (선택사상기법을 이용한 GFDM의 최대전력 대 평균전력 비 감소기법)

  • Oh, Hyunmyung;Yang, Hyun Jong
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.41 no.6
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    • pp.698-706
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    • 2016
  • Orthogonal frequency division multiplexing (OFDM) has high peak to power ratio (PAPR). High PAPR makes problems such as signal distortion and circuit cost increasing. To solve the problemsm several PAPR reduction methods have been proposed. However, synchronization and orthogonality in OFDM systems may be a limitation to reduce latency for 5G networks. Generalized frequency division multiplexing (GFDM) is one of the possible solutions for asynchronous and non-orthogonal systems, which are more preferable to reduce the latency. However, multiple subsymbols in GFDM result in more superposition in time domain, GFDM has higher PAPR. Selective mapping (SLM) is one of PAPR reduction techniques in OFDM, which uses phase shift. The PAPR of GFDM SLM is compared to conventional GFDM and OFDM SLM in terms of PAPR reduction enhancement via numerical simulations. In addition, the out-of-band performance is analyzed in the aspect of asynchronous condition interference.