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2차원 선형보간법을 이용한 OFDM MIMO 시스템에서의 채널 추정
오태열,안성수,최승원 (사)디지털산업정보학회 2011 디지털산업정보학회논문지 Vol.7 No.3
An OFDMA(Orthogonal Frequency Division Multiple Access) includes a MIMO(Multi-Input Multi-Output) scheme for improving spectral efficiency and data throughput. Recognizing that the performance of MIMO system is heavily dependent upon the accuracy of channel estimation, we propose a novel channel estimation for the MIMO scheme based on OFDMA. Conventional interpolation-based channel estimation suffers from poor estimation error at specific subcarriers. Proposed scheme makes use of a planar interpolation instead of linear interpolation for those subcarriers of bad accuracy. Simulation results show that the proposed scheme improves the performance of MIMO system by improving the accuracy in channel estimation especially for the adverse subcarrier positions. It is observed that the proposed scheme outperforms the conventional method by about 2dB in terms of both mean squared error and overall bit error rate with a reasonable computational complexity.
WiBro 다운링크 환경에서 여러 가지 MIMO 기법의 성능 및 연산량에 대한 비교 연구
홍경화,오태열,최승원 (사)디지털산업정보학회 2008 디지털산업정보학회논문지 Vol.4 No.2
Combining OFDMA with MIMO is the key technology for the 4G mobile communication. OFDMA can relieve inhernet difficulties of high-speed transmission. MIMO technology can be largely categorized into two techniques: ibe us STC fir duversity gain and the other is SM for high frequency efficiency, In this paper, we deouct various MIMO techniques of two tranmit antenna and compare the computational complexity of decoding process for the techniques. Then, we analysis the performance of the techniques in the WiBro downlink environment based on OFDMA. We perfer ML algorithm which is the optimum performance and ZF algorithm of least computational complexity for SM detection.
다중경로 페이딩 환경에서 와이브로 스마트 안테나 시스템의 적응 빔포밍 기술 연구
최승원,조용진,오태열,정재호 한국정보통신설비학회 2008 한국정보통신설비학회 학술대회 Vol.2008 No.1
Multiple antenna technology, such as multiple input multiple output (MIMO), beamforming is one of the most promising technology for broadband wireless communication. In OFDM environment, we found that as the number of paths is increased, smart antenna system cannot fully exploit beamforming gain. In this paper, we propose a beamforming scheme and analyze the performance of the proposed beamforming scheme in WiBro smart antenna system. WiBro is an OFDMA-based multiple access service for wireless broadband multimedia environment. The proposed beamforming technique for WiBro smart antenna system can effectively improve the performance of the systems in multipath fading environment.