하향링크 MC-CDMA 시스템을 위한 CM 기반의 블라인드 적응 수신기 = Blind Adaptive Receiver based on Constant Modulus for Downlink MC-CDMA Systems

국문 초록 (Abstract)

본 논문에서는 간단한 시공간 블록 부호 (STBC)를 적용한 MC-CDMA 시스템에서 상수 모듈러스 (CM) 기반의블라인드 적응 수신기를 설계하는 방법을 제시한다. 전송 심볼들을 검파하기 위하여 사용되는 여파기 계수 벡터들을 부분 벡터들로 분할하고, CM 메트릭을 최소화시키는 최적의 부분 벡터들 간의 특별한 관계식을 유도한다. 이러한 특별한관계를 이용하여 변형된 CM 메트릭을 제시한다. 그리고 나서, 변형된 CM 메트릭을 최소화시키는 블라인드 적응형 통계적 변화율 CM 알고리즘 (SG-CMA)을 제안한다. 제안하는 기법의 여파기 계수 벡터들은 유도한 특별한 관계를 만족하는영역에서만 갱신되기 때문에, 제안하는 블라인드 적응 SG-CMA 기법이 기존의 SG-CMA 기법보다 더 빠른 수렴 속도를갖는다. 그리고, 컴퓨터 모의실험을 통하여, 제안하는 SG-CMA 기법의 우수성을 검증한다.

다국어 초록 (Multilingual Abstract)

In this paper, we consider a constant modulus (CM) based blind adaptive receiver design for downlink multi-carrier code-division multiple access (MC-CDMA) systems employing simple space-time block coding (STBC). In the paper, filter weight vectors used for the detection of the transmitted symbols are partitioned into its subvectors and then, special relations among the optimal subvectors minimizing the CM metric are derived. Using the special relations, we present a modified CM metric and propose a new blind adaptive stochastic-gradient CM algorithm (SG-CMA) by minimizing the modified CM metric.
The proposed blind adaptive SG-CMA has faster convergence rate than the conventional SG-CMA because the filter weight vectors of the proposed scheme are updated in the region of satisfying the derived special relations. Computer simulation results are given to verify the superiority of the proposed SG-CMA.

참고문헌 (Reference)

1 Lukas Landau, "Robust adaptive beamforming algorithms using the constrained constant modulus criterion" Institution of Engineering and Technology (IET) 8 (8): 447-457, 2014

2 Min Li, "Precoding for the Sparsely Spread MC-CDMA Downlink With Discrete-Alphabet Inputs" Institute of Electrical and Electronics Engineers (IEEE) 66 (66): 1116-1129, 2017

3 진익수, "Performance of STBC-MTCM/TCM Systems for High Rate Transmissions" 한국정보기술학회 14 (14): 99-105, 2016

4 Z. Li, "Nonblind and Semiblind Space–Time-Frequency Multiuser Detection for Space–Time Block-Coded MC-CDMA" Institute of Electrical and Electronics Engineers (IEEE) 4 (4): 1311-1318, 2005

5 Henry Ramiro Carvajal Mora, "Mean Bit Error Rate Evaluation of MC-CDMA Cellular Systems Employing Multiuser-Maximum-Likelihood Detector" Institute of Electrical and Electronics Engineers (IEEE) 66 (66): 9838-9851, 2017

6 Jung-lang Yu, "MIMO Capon Receiver and Channel Estimation for Space-Time Coded CDMA Systems" Institute of Electrical and Electronics Engineers (IEEE) 5 (5): 3023-3028, 2006

7 Tsui-Tsai Lin, "MCMOE-Based CFO Estimator Aided With the Correlation Matrix Approach for Alamouti's STBC MC-CDMA Downlink Systems" Institute of Electrical and Electronics Engineers (IEEE) 61 (61): 3790-3795, 2012

8 Mohammad Torabi, "Impact of Antenna Correlation on the BER Performance of a Cognitive Radio Network with Alamouti STBC" Institute of Electrical and Electronics Engineers (IEEE) 5 (5): 264-267, 2016

9 T.E. Biedka, "Convergence analysis of the least squares constant modulus algorithm in interference cancellation applications" Institute of Electrical and Electronics Engineers (IEEE) 48 (48): 491-501, 2000

10 Yuantao Gu, "Convergence analysis of a deficient-length LMS filter and optimal-length sequence to model exponential decay impulse response" Institute of Electrical and Electronics Engineers (IEEE) 10 (10): 4-7, 2003

11 M. Honig, "Blind adaptive multiuser detection" Institute of Electrical and Electronics Engineers (IEEE) 41 (41): 944-960, 1995

12 Zhengyuan Xu, "Blind adaptive algorithms for minimum variance CDMA receivers" Institute of Electrical and Electronics Engineers (IEEE) 49 (49): 180-194, 2001

13 Rodrigo De Lamare, "Blind adaptive MIMO receivers for space-time block-coded DS-CDMA systems in multipath channels using the constant modulus criterion" Institute of Electrical and Electronics Engineers (IEEE) 58 (58): 21-27, 2010

14 J. Choi, "Adaptive and Iterative Signal Processing in Communications" Cambridge University Press 2006

15 Xiaomin Wu, "Adaptive Widely Linear Constrained Constant Modulus Reduced-Rank Beamforming" Institute of Electrical and Electronics Engineers (IEEE) 53 (53): 477-492, 2017

16 K. Shi, "A variable step size and variable tap length LMS algorithm for impulse response with exponential power profile" 3105-3108, 2009

17 S.M. Alamouti, "A simple transmit diversity technique for wireless communications" Institute of Electrical and Electronics Engineers (IEEE) 16 (16): 1451-1458, 1998

18 Guang Yang, "A Kalman Filter-Based Blind Adaptive Multi-User Detection Algorithm for Underwater Acoustic Networks" Institute of Electrical and Electronics Engineers (IEEE) 16 (16): 4023-4033, 2016

19 임승각, "2차원 QAM 신호에서 CR-MMA와 FC-MMA 적응 등화 알고리즘의 성능 비교" 한국인터넷방송통신학회 18 (18): 85-90, 2018