大型天線陣列(Massive-MIMO)是未來5G通訊發展中其中一樣重要的技術，藉由基地台擺放非常大數量的天線，帶來通道容量與能量效益的大幅提升。但是由於實際系統中，天線的數量不可能無上限的增加，另外，擺放天線的物理空間也有一定量的大小限制，使得天線之間距離過近而造成產生的通道之間彼此具有相關性，進而限制了大型天線陣列(Massive-MIMO)所帶來的效益。本論文考慮在有限的物理空間上擺放多根天線，使用簡單的線性預編碼方式(如Zero-Forcing Precoding、Match-Filter Precoding)，討論擺設天線的物理空間大小、相關性與通道容量之間的關係。透過天線選擇與用戶選擇的方式，比較不同的線性預編碼方式所產生的效果，進而提升通道容量與減少使用的天線量。

Massive multiuser-multiple-input-multiple-output (Massive MIMO) brings significantly improvement in channel capacity and energy efficiency via placing a great number of antennas at base station (BS). But in the real system, it is impossible to increase the number of antennas without limit. Therefore, we consider a system with large number of antennas in fixed physical antenna space, and use simple linear precoding (i.e. Zero-Forcing Precoding, Match-Filter Precoding), discuss the relationship to the physical space, correlation and channel capacity. In this thesis, we also compare the performance of different precoding method by user selection to improve the channel capacity.

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