多輸入輸出毫米波系統與大規模陣列天線是能為下一世代行動通訊提供高吞吐量的重要技術。為了減少因大量天線的射頻鏈與數位類比轉換器所造成的高成本和功耗，在毫米波多輸入輸出系統中，數位類比混合式預編碼是具潛力架構之一。然而毫米波的通訊系統期望能夠操作在有頻率選擇性的寬帶通道中。在這篇論文中，我們提出了一個基於正交分頻多工技術且適用於寬頻多輸入輸出毫米波系統中不具反矩陣運算的低複雜度混合式預編碼演算法。因為在傳送端與接收端的反快速傅立葉轉換和快速傅立葉轉換處理器，所以在這個具頻率選擇性通道中要解的問題是找到一個所有子載波共有的射頻預編碼與每個子載波各自擁有的基頻預編碼。在運算射頻預編碼中，採用了連續干擾消除的概念去解決了反矩陣計算的問題。最後模擬結果顯示本論文所提出的演算法與論文內提及的演算法相比較，可以減少運算複雜度，並且效能損失是可忽略的。

Millimeter wave (mmWave) multiple-input and multiple-output (MIMO) system with large-scale antenna arrays is a key technique to provide high throughput for the next generation communication systems. To reduce the high cost and power consumption of radio frequency (RF) chains and data converters, the hybrid analog/digital precoding is the potential candidate for mmWave MIMO systems. However, the communication of mmWave systems is expected to employ on broadband channel with frequency selectivity. In this thesis, we propose a matrix-inversion-bypass hybrid precoding and combining algorithm for mmWave MIMO system with orthogonal frequency division multiplexing (OFDM) modulation. Due to the inverse fast Fourier transform (IFFT) and fast Fourier transform (FFT) processors in the transmitter and receiver, the problem of hybrid precoding for frequency selective channel is to find the shared common RF precoder for all subcarriers and individual baseband precoders for each subcarrier. By adopting the concept of the successive interference cancellation, the problem of the matrix inversion can be solved in calculating the RF precoder. The simulations show that the proposed algorithm can reduce the computational complexity with negligible performance loss comparing to the mentioned work in this thesis.

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