DOI QR코드

DOI QR Code

OFDM 신호의 PAPR 감소를 위한 적응적 톤 예약 기법

An Adaptive Tone Reservation Scheme for PAPR Reduction of OFDM Signals

  • 양모찬 (한화시스템 지상시스템팀)
  • 투고 : 2019.08.01
  • 심사 : 2019.10.15
  • 발행 : 2019.10.31

초록

OFDM(Orthogonal Frequency Division Multiplexing) 전송 신호의 PAPR (Peak-to-Average Power Ratio)을 효과적으로 감소시키기 위하여 클리핑 잡음 (Clipping Noise)을 이용한 적응적 톤 삽입 (Adaptive Tone Reservation; ATR) 기법을 제안한다. 제안된 ATR 기법은 기존 TR 방법에서의 복잡도 문제를 개선하기 위해, IFFT (Inverse Fast Fourier Transform) 출력 가운데 임계 진폭값 보다 큰 신호들을 클리핑 하는 과정, 클리핑된 신호에 대해 클리핑 잡음을 계산 후 주파수 영역 클리핑 잡음의 심벌 중에서 가장 큰 전력이 할당된 톤을 추출하는 과정, 추출된 톤을 예약하여 PAPR을 감소하는 과정의 총 3단계로 구성된다. 모의실험 결과, 제안된 ATR 기법은 톤 예약이 가능한 최적의 톤을 클리핑 잡음을 이용하여 추출함으로써 기존 TR 방법의 계산량을 획기적으로 줄이면서도 성능이 최적의 TR 방법에 근접한 것을 보여준다.

We propose an ATR (Adaptive Tone Reservation) scheme based on clipping noise for PAPR (Peak-to-Average Power Ratio) reduction of OFDM (Orthogonal Frequency Division Multiplexing) signals. The proposed scheme is composed of three steps: clipping, tone selection, and TR procedures. In the first step, the peak samples in the IFFT (Inverse Fast Fourier Transform) outputs are scaled down by clipping. In the second step, the sub-carrier position where the power of the clipping noise is the maximum, is selected. Finally, the generic TR procedure is performed. Simulation results show that the proposed scheme does not require all the possible combinations for the original TR procedures, while maintaining the PAPR reduction performance.

키워드

참고문헌

  1. L. Hanzo, M. Munster, B. J. Choi, and T. Keller, OFDM and MC-CDMA for Broadband Multi-user Communications, WLANs and Broadcasting. 발행도시: John Wiley & Sons, 2003.
  2. P. van Nee and R. Prasad, OFDM for Wireless Multimedia Communications. 발행도시: Artech House Publishers, 2000.
  3. S. Li, H. Kwon, and S. Kang, "An Approximated Model of the Coefficients for Interchannel Interference of OFDM System with Frequency Offset," J. of the Korea Institute of Electronic Communication Sciences, vol. 13, no. 5, 2018, pp. 917-922. https://doi.org/10.13067/JKIECS.2018.13.5.917
  4. S. Hwang, "Channel Estimation Based on LMS Algorithm for MIMO-OFDM System," J. of the Korea Institute of Electronic Communication Sciences, vol. 7, no. 6, 2012, pp. 1455-1461. https://doi.org/10.13067/JKIECS.2012.7.6.1455
  5. H. Chen and S. Kang, "An Interchannel Interference Self-Cancellation Scheme for the Orthogonal Frequency Division Multiplexing System," J. of the Korea Institute of Electronic Communication Sciences, vol. 13, no 4, 2018, pp. 729-736. https://doi.org/10.13067/JKIECS.2018.13.4.729
  6. X. Li and L. J. Cimini, "Effects of clipping and filtering on the performance of OFDM," Proc. VTC '97, Phoenix, USA, May 1997, pp. 1634-1638.
  7. X. Wang, T. T. Yjhung, and C. S. Ng, "Reduction of peak-to-average power ratio of OFDM system using a companding technique," IEEE Trans. Broadcast., vol. 45, no. 9, Sept. 1999, pp. 303-307. https://doi.org/10.1109/11.796272
  8. R. W. Bauml, R. F. H. Fischer, and J. B. Huber, "Reducing the peak-to-average power ratio of multicarrier modulation by selective mapping," IEE Electr. Lett., vol. 32, Oct. 1996, pp. 2056-2057. https://doi.org/10.1049/el:19961384
  9. L. Cimini, Jr. and N. Sollenberger, "Peak-to-average power ratio reduction of OFDM signal using partial transmit sequences," IEEE Commun. Lett., vol. 4, no. 3, Mar. 2000, pp. 86-88. https://doi.org/10.1109/4234.831033
  10. J. Tellado, "Peak to average power reduction for multicarrier modulation," Ph. D. dissertation, Stanford University, 2000.
  11. B. S. Krongold and D. L. Jones, "An active-set approach for OFDM PAR reduction via tone reservation," IEEE Trans. Signal Proc., vol. 52, no. 2, Feb. 2004, pp. 495-509. https://doi.org/10.1109/TSP.2003.821110
  12. S. Han and J. Lee, "Peak-to-average power ratio reduction of an OFDM signal by PAPR reduction sub-carriers," Proc. APWCS 2004, Seoul, Korea, Jan. 2004, pp. 3-6.
  13. E. Lawley and C. J. Kikkert, "Peak-to-average power ratio reduction of OFDM signals using peak reduction carriers," Proc. ISSPA '99, Brisbane, Australia, Aug. 1999, pp. 737-740.
  14. C. Tellambura, "Computation of the continuous-time PAR of an OFDM signal with BPSK subcarriers," IEEE Commun. Lett., vol. 5, no. 5, May 2001, pp. 185-187. https://doi.org/10.1109/4234.922754