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Channel Modeling And Resource Allocation In Ofdm Systems, Xiang Gao
Channel Modeling And Resource Allocation In Ofdm Systems, Xiang Gao
LSU Doctoral Dissertations
The increasing demand for high data rate in wireless communication systems gives rise to broadband communication systems. The radio channel is plagued by multipath propagation, which causes frequency-selective fading in broadband signals. Orthogonal Frequency-Division Multiplexing (OFDM) is a modulation scheme specifically designed to facilitate high-speed data transmission over frequency-selective fading channels. The problem of channel modeling in the frequency domain is first investigated for the wideband and ultra wideband wireless channels. The channel is converted into an equivalent discrete channel by uniformly sampling the continuous channel frequency response (CFR), which results in a discrete CFR. A necessary and sufficient condition …
Exploring The Hot-Carrier Effect On The Wireless Transceivers, Sameer R. Herlekar
Exploring The Hot-Carrier Effect On The Wireless Transceivers, Sameer R. Herlekar
LSU Doctoral Dissertations
Phase noise can be regarded as the most severe cause of performance degradation in the wireless communication systems. The hot-carriers (HCs), found in the CMOS synchronization circuits, are the high-energy charge carriers that degrade the MOSFET devices’ performance by increasing the threshold voltage required to operate the MOSFETs. The HC effect manifests itself as the phase noise whose level increases with the continued MOSFET operation and such increases result in the performance degradation of the voltage-controlled oscillator (VCO) built on the MOSFETs. The HC effect is particularly evident in the short-channel MOSFET devices. In this dissertation, we analyze the wireless …
Interference Suppression And Parameter Estimation In Wireless Communication Systems Over Time-Varing Multipath Fading Channels, Jianqiang He
Interference Suppression And Parameter Estimation In Wireless Communication Systems Over Time-Varing Multipath Fading Channels, Jianqiang He
LSU Doctoral Dissertations
This dissertation focuses on providing solutions to two of the most important problems in wireless communication systems design, namely, 1) the interference suppression, and 2) the channel parameter estimation in wireless communication systems over time-varying multipath fading channels. We first study the interference suppression problem in various communication systems under a unified multirate transmultiplexer model. A state-space approach that achieves the optimal realizable equalization (suppression of inter-symbol interference) is proposed, where the Kalman filter is applied to obtain the minimum mean squared error estimate of the transmitted symbols. The properties of the optimal realizable equalizer are analyzed. Its relations with …