摘要
本論文研究一個無線動態系統狀態預估的問題，其中，卡爾曼濾波器經由無線衰 減的通道接收感測器所傳送的觀測信號，傳送中的觀測信號可能因為嚴重的通道衰 減效應而大幅降低訊號品質，所以我們提出兩種並行的方法以剋服此效應的衝擊， 藉此提高通訊品質並增強卡爾曼濾波器的估測精度。首先，在感測器端提出一個基 於閾值的機會式排程法使卡爾曼濾波器不會接收到嚴重衰弱的信號。接著，我們在 感測器端或接收端加入多天線傳輸機制，以實現多樣性傳輸通道，而藉此提升通道 增益。我們根據不同形態的多天線傳輸系統，例如單輸入多輸出、多輸入單輸出及 多輸入多輸出，並依據取感測器端取得不同多寡的通道狀態，推導出在不同狀況下 對應的卡爾曼濾波器穩定條件。最後，我們研究基於機會式排程法的多通道傳輸系 統的能量效益，證明利用滿足穩定條件的最大閾值可以達到相對最大的能量效益。
並列摘要
In this thesis, we study the state estimation problem of a wireless linear dynamic system in which the Kalman filter receives the observation signals transmitted by sensors over wire- less fading channels. Since the transmitted observations would be severely weakened while the wireless channels are in deep fade, we propose a threshold-based opportunistic schedul- ing scheme for the sensors in order to make the signals received by the Kalman filter not fairly weak. In addition to that, we implement the diversity channels by multiple antenna communications (e.g., single-input-multi-output (SIMO), multi-input-single-output (MISO), and multi-input-multi-output (MIMO)) to enhance the channel gain and eliminate the impact from fading effect. Different situations such as has perfect channel state information (CSI), lacks in getting CSI or obtains partial CSI on both the sensor side and the Kalman filter side are taken into account. The stability condition in each circumstance is derived, which characterize the fundamental limits between the scheduling threshold and the system matrices of the linear dynamical system. Finally, the energy efficiency of the proposed opportunistic scheduling scheme over diversity channels is studied and we show that the maximum energy efficiency can be achieved by utilizing the maximum scheduling threshold which satisfies the stability condition.