由於高速室內無線通訊的需求提高，六十秭赫頻帶的通訊技術受到極高的關注。利用此頻帶通訊的優勢包含高傳輸速率及廣大的無需執照頻寬。然而，在無線傳輸系統下，六十秭赫電磁波的短波長特性導致嚴重的路徑耗損。為了降低路徑耗損，可以採用正交分頻多工(orthogonal frequency-division multiplexing, OFDM)搭配波束成型技術來彌補。此外，使用波束成型技術產生多波束，再利用多波束傳輸多個訊息串，達到增加系統容量的目的。
在本論文中，我們將多波束成型正交分頻多工系統應用於六十秭赫頻帶。由於IEEE 802.15.3c的通道模型對於六十秭赫通道路徑的時空分布有明確的定義，因此採用此通道模型。針對通道路徑時間及空間的隨機特性，我們藉由精確的數學分析來取得路徑的平均效應，進而求得系統的訊號干擾雜訊比(signal-to-interference-plus-noise ratio, SINR)以及容量邊界。同時，以直觀角度設計多波束成型方法來增加系統的傳輸量。接著利用數值模擬來驗證數學分析的可靠性。最後，利用分析的結果來探討不同波束成型方法對系統的影響。

For the increasing demand for high-rate indoor wireless communications, 60 GHz frequency bands have attracted much attention. The advantages of 60 GHz bands include high data
rates and wide unlicensed bandwidth which is available worldwide. However, small wavelength of 60 GHz bands causes high path loss. To mitigate the path loss and increase the
system capacity, the multibeam beam-forming orthogonal frequency-division multiplexing (OFDM) technique can be applied.
In the thesis, multibeam beam-forming OFDM systems in 60 GHz bands are considered. The IEEE 802.15.3c channel model which describes the statistical behavior of 60 GHz channels
in temporal and spatial domains is employed. One of our contributions is to characterize the effect of random multipaths in 60 GHz systems by exact mathematical analysis. Based on the analysis, some multi-stream beam-forming schemes are devised to enhance the system capacity. Precise system analysis is verified by numerical simulations. Finally, performance of different beam-forming schemes are discussed and compared.

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