오비누투주맵의 직접 결합 세포사멸 기전에 있어서 스핑고지질의 역할

prohibition석

OFDMA 시스템에서의 효율적인 제한적 채널 피드백에 관한 연구

학위논문(석사) - 한국과학기술원 : 전기 및 전자공학과, 2010.08, [ vi, 32 p. ]An orthogonal frequency-division multiple access (OFDMA) is one of the most promising technologies which supports high data rates and various QoS (quality of service) profiles for multiple users imposed on future wireless communication systems. To get an enhanced capacity from the adaptive resource allocation in OFDMA systems, the transmitter needs channel state information (CSI) between the transmitter and receiver. In this thesis, we propose two new limited channel feedback algorithms for SISO (single input single output)- and MIMO (multiple input multiple output)-OFDMA systems, respectively. Firstly, a novel limited channel feedback algorithm for SISO-OFDMA systems is presented. The key idea is to report CSI of relative maximum and minimum points of the channel gain from users to BS. Secondly, an efficient limited channel feedback algorithm designed to improve feedback resource uitlization for MIMO-OFDMA systems is presented. The key idea is to adaptively control the amount of the feedback by considering the channel state information and the system objective function. The simulation results show that the proposed algorithms outperform the conventional limited channel feedback algorithms.한국과학기술원 : 전기 및 전자공학과