Journal of Advanced Marine Engineering and Technology

The Korean Society of Marine Engineering (한국마린엔지니어링학회)
권호 표지
DOI QR코드

DOI QR Code

Improving the PTS Method for the PAPR Reduction in the OFDM System

OFDM 시스템에서 PAPR 감소를 위한 PTS 기법의 성능개선

  • 김동식 (한국해양대학교 전파공학과) ;
  • 곽민길 (한국해양대학교 전파공학과) ;
  • 조형래 (한국해양대학교 전파공학과)
  • Received : 2010.10.05
  • Accepted : 2010.11.18
  • Published : 2010.11.30
Download PDF
⟨ Previous Next ⟩

Abstract

The OFDM system has better characteristics in transmission rate, power efficiency, bandwidth efficiency, impulse-noise immunity, and narrow band interference immunity etc. in comparison with other conventional systems. However, high PAPR of an OFDM signals causes some serious non-linear processing of RF amplifier. And performance of the communication system gets worse. Therefore, various methods reducing PAPR of an OFDM skills such as the clipping method, block coding method, and phase rotation method etc. have been researched. In this paper, we propose a high-speed adaptive PTS method which eliminates high PAPR. And we compare the proposed method with other conventional methods. The proposed method has decreased quantity of calculation compare with an adaptive PTS method. Of course, The more its calculation amount is decreased, the more its BER characteristic is not better than an adaptive PTS method. However, keeping up satisfactory BER performance, we highly improved calculation amount of a PTS method.

OFDM(Orthogonal Frequency Division Multiplexing) 통신 시스템은 단일 반송파를 사용해 정보를 전송하는 대신, 주파수의 직교성을 활용하여 정보 전송률이 낮은 다수의 부반송파로 나누어 전송하므로 주파수 사용 효율과 고속의 데이터 전송에서 우수한 특성을 가지는 기술이다. 그러나 OFDM 신호는 단일 반송파 전송방식에 비하여 PAPR(Peak-to-Average Power Ratio)이 증가하는 문제점이 있다. PAPR이 증가하면 RF 증폭기가 비선형적으로 동작하게 되어 효율이 감소하게 된다. 따라서 OFDM에서는 PAPR을 감쇄시키기 위하여 다양한 기법들이 사용되고 있다. 본 논문에서는 PTS(Partial Transfer Sequence) 기법의 단점인 많은 수의 IFFT(Inverse Fast Fourier Transform) 로 인한 연산의 복잡도가 급격하게 증가하는 부분을 개선하기위해 기존의 PTS 기법을 개선하여 두 개의 임계 레벨을 가지는 PTS 기법을 제안하였다. PAPR 값을 비교 분석한 결과, 기존의 PTS 기법과 근사한 BER(Bit Error Rate) 특성을 유지하면서 연산량을 크게 개선시킬 수 있음을 확인 하였다.

Keywords

References

  1. Richard Van Nee and Ranjee Prasad, OFDM for Wirless Multimedia Commnications, Artech House, pp. 33-51, 2000.
  2. 조용수, 김재권, 양원영, MIMO-OFDM 무선통신과 MATLAB, 홍릉과학출판사, 2008.
  3. Xiaodong Li and L. J. Cimini Jr., "Effects of clipping and filtering on the performance of OFDM," IEEE Trans. on Communications, vol. 39, no. 7, pp. 1031-1033, 1991. https://doi.org/10.1109/26.87205
  4. T. A. Wilkinson and A. E. Jones, "Minimization of the peak-to-mean envelope power ratio of multicarrier transmission schemes by block coding," Proc. of IEEE VTC '95, Chicago, pp. 825-829, 1995.
  5. H. Ochiai and H. Imai,"Block coding scheme based on complementary sequences for multicarrier signals," IEICE Trans. On Fundamentals, pp. 2136-2143, 1997.
  6. R. W. Baumi, R. F. Fischer, and J. B. Huber, "Reducing the peak-to-average power ratio of multicarrier modulation by selec tive mapping," IEE Electronic Letters, vol.32, no.22, pp. 2056-2057, 1996. https://doi.org/10.1049/el:19961384
  7. A. D. S Jayalath and C. Tellamburg, H. Wu, "Reduced complexity PTS and new phase sequence for SLM to reduce PAP of an OFDM signal," IEEE VTC 2000, vol.3, pp. 1914-1917, 2000.
  8. L. J. Cimini and N. R. Sollenberger, "Peak-to-Average power ratio reduction of an OFDM signal using partial transmit sequences," IEEE International Conference on Communications, vol. 1, pp. 511-515, 1999.
  9. C.Tllambura, "Phase optimization criterion for reducing peak-to-average power ratio of an OFDM signal," IEE Electro. Letters vol. 34, pp. 169-170, 1998. https://doi.org/10.1049/el:19980163
  10. S. G. Kang, J. G. Kim, and E. K. Joo, "A novel subblock partition scheme for partial transmit sequence OFDM," IEEE Transactions on Broadcasting, vol. 45, no. 3, pp. 333-338, 1999. https://doi.org/10.1109/11.796276
  11. R. Dinis and A. Gusmao, "A new class of signal processing schemes for bandwidth-efficient OFDM transmission with low envelope fluctuation," in Proc. VTC, pp. 658-662, 2001.
  12. 공민한, 송문규, "OFDM 신호의 PAPR 감소를 위한 낮은 복잡도를 갖는 PTS 기법," 전자공학회 논문지, 제45권 TC편 제1호, 2008년 1월.