Channel State Based Switching between Diversity and Multiplexing in MIMO Systems

[[abstract]]在多輸入多輸出（MIMO）無線通訊系統中，有兩個流行的方法可以改善品質、容量和可靠性：分集和（空間多工）。分集的技術是將相同的資訊在多根天線下傳輸，然後在天線上的所有接收信號都會被結合起來以加強通訊的可靠性；而對多工技術來說，資料串流被分作許多的子串流，每個子串流在不同的天線上傳送或接收來增加通訊的容量。很明顯，在多輸入多輸出系統中分集和多工間將有一個取捨的問題，所以在分集和多工之間的切換將是增強多輸入多輸出系統的一個有效的方法。在這個理論中，我們使用最小歐幾里德距離來切換多輸入多輸出系統中的分集與多工。模擬結果顯示此切換的架構將比單獨使用分集或多工的技術擁有更低的位元錯誤率。[[abstract]]There are two popular approaches for improving quality, capacity and reliability in multiple-input multiple-output (MIMO) systems: diversity and (spatial) multiplexing. For diversity, the same information is transmitted over multiple antenna elements, and then the received signals on all antenna elements are combined to enhance the reliability, while for multiplexing, the data stream is divided into multiple substreams, and each substream is transmitted and received over a different antenna element to increase the capacity. It is clear that there is a tradeoff between diversity and multiplexing in MIMO systems, so switching between diversity and multiplexing should be an effective approach for enhancing the MIMO systems. In this thesis, we use the minimum Euclidean distance for switching between diversity and multiplexing in MIMO systems. Simulation results show that such a switching scheme can give smaller bit error probability than the MIMO scheme with diversity or multiplexing being solely employed.[[note]]碩