스마트안테나를 적용한 OFDM 시스템의 상향링크 동기화 기법
An Uplink Synchronization Method for OFDMA Systems with Smart Antenna
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초록
본 논문에서는 스마트 안테나를 갖는 OFDMA 시스템의 상향링크에 적합한 CFO 동기화 기법 및 안테나 가중치 벡터 추정 기법을 제안한다. 제안된 CFO 동기화 기법은 상향링크에서 별도의 동기화 심볼을 전송하지 않고 안테나 가중치 벡터 계산을 위해 전송되는 훈련심볼을 사용하여 CFO를 추정하며 폐루프 과정없이 추정된 CFO를 기지국에서 보상한다. 모의실험을 통해 동일 대역을 사용하는 다른 CFO를 갖는 단말들의 간섭 영향 없이 원하는 사용자의 CFO를 추정할 수 있음을 확인하고, 다른 단말의 CFO는 안테나 가중치 벡터 계산 과정을 통해 널 빔을 형성함으로써 효과적으로 제거할 수 있음을 확인한다.
Abstract
In this paper, a method of uplink carrier frequency offsets (CFO) synchronization and adaptive beamformingis proposed for orthogonal frequency division multiple access (OFDMA) systems with smart antenna. The proposed method does not require an additional synchronization and preamble for uplink CFO or feedback loop for initial synchronization. An estimation method for uplink CFO is proposed for spatial division multiple access environments where interference signals from other users are present at the same frequency band with different CFOs. Itis shown by computer simulation that the proposed synchronization and beamforming method forms a beam in the direction of a desired user with CFO compensated, whole it places nulls in the direction of other users with different CFOs.
참고문헌 (14)
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