The Journal of Korean Institute of Communications and Information Sciences (한국통신학회논문지)

The Korean Institute of Commucations and Information Sciences (한국통신학회)
권호 표지

An Adaptive Tone Injection Scheme using Clipping Noise for PAPR Reduction of OFDM Signals

OFDM 신호의 PAPR 감소를 위해 클리핑 잡음을 이용한 적응적 톤 삽입 기법

  • 양모찬 (숭실대학교 정보통신공학부) ;
  • 신요안 (숭실대학교 정보통신공학부)
  • Published : 2009.11.30
Download PDF
⟨ Previous Next ⟩

Abstract

We propose an ATI (Adaptive Tone Injection) 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 TI 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 TI procedure is performed. Simulation results show that the proposed scheme does not require all the possible combinations of the original TI procedures, while maintaining the PAPR reduction performance.

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 Injection; ATI) 기법을 제안한다. 제안된 ATI 기법은 기존 TI 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 확장된 성상도로 맵핑 후에 부분적으로 IFFT 하는 과정의 총 3단계로 구성된다. 모의실험 결과, 제안된 ATI 기법은 맵핑이 가능한 최적의 톤을 클리핑 잡음을 이용하여 추출함으로써 기존 TI 방법에서와는 달리 본래신호와 동일한 정보를 가지는 등가 신호의 가능한 모든 조합을 필요로 하지 않으며, OFDM PAPR 감소 성능 역시 최적의 TI 방법에 근접함을 보여준다.

Keywords

References

  1. L. Hanzo, M. Munster, B. J. Choi, and T. Keller, OFDM and MC-CDMA for Broadband Multi-user Communications, WLANs and Broadcasting, John Wiley & Sons, 2003
  2. P. van Nee and R. Prasad, OFDM for Wireless Multimedia Communications, Artech House Publishers, 2000
  3. X. Li and L. J. Cimini, 'Effects of clipping and filtering on the performance of OFDM,' Proc. VTC '97, pp. 1634-1638, Phoenix, USA, May 1997
  4. 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, pp. 303-307, Sept. 1999 https://doi.org/10.1109/11.796272
  5. 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, pp. 2056-2057, Oct. 1996 https://doi.org/10.1049/el:19961384
  6. 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, pp. 86-88, Mar. 2000 https://doi.org/10.1109/4234.831033
  7. J. Tellado, 'Peak to average power reduction for multicarrier modulation,' Ph. D. dissertation, Stanford University, Stanford, USA, 2000
  8. 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, pp. 495-509, Feb. 2004 https://doi.org/10.1109/TSP.2003.821110
  9. S. Han and J. Lee, 'Peak-to-average power ratio reduction of an OFDM signal by PAPR reduction sub-carriers,' Proc. APWCS 2004, pp. 3-6, Seoul, Korea, Jan. 2004
  10. E. Lawley and C. J. Kikkert, 'Peak-to-average power ratio reduction of OFDM signals using peak reduction carriers,' Proc. ISSPA '99, pp. 737-740, Brisbane, Australia, Aug. 1999
  11. C. Tellambura, 'Computation of the continuous-time PAR of an OFDM signal with BPSK subcarriers,' IEEE Commun. Lett., vol. 5, no. 5, pp. 185-187, May 2001 https://doi.org/10.1109/4234.922754