【電信學】【2007】慢變及快變通道中的MIMO系統
本文為波蘭克拉科夫AGH科技大學（作者：Paweł Kułakowski）的博士論文，共133頁。
眾所周知，多輸入多輸出(MIMO)系統能夠增加無線鏈路的吞吐量，並克服多徑衰落的影響。然而，MIMO系統在無線網路標準中的整合是緩慢的，因為還有許多問題尚未解決。這篇博士論文涉及慢變化和快變化無線通道中的MIMO系統。首先，考慮MIMO系統的一般問題，討論了多路複用增益和分集的概念、通道知識、編碼技術、多使用者接入和寬頻傳輸。接下來，研究MIMO系統的通道特性，解決了多徑傳播、通道模型、無線通道變化和通道估計的問題。然後，作者對慢變、快變MIMO通道進行了研究。對以下內容進行建模並予以證明：
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通過選擇合適的接入點位置和天線，可以顯著提高室內MIMO系統慢變無線通道的資料吞吐量。 -
迭代通道估計（ICE）演算法允許在不頻繁傳輸訓練序列的情況下降低快變無線通道中的誤位元速率。
上述第一條是基於慢變MIMO通道的數值射線追蹤計算的，它指出了接入點天線位置、間隔和特性如何影響系統吞吐量。第二條是基於快變通道的ICE演算法，ICE演算法能夠在資料傳輸的同時進行通道估計。當應用ICE演算法時，可以降低誤位元速率——在某些情況下，誤位元速率能夠降低50倍以上。
Multiple-input multiple-output (MIMO)systems are well known as a technique which allows increasing the throughput ofa radio link and overcoming the effects of multipath fading. However, the integrationof MIMO systems into the standards of wireless networks is slow, as there arenumerous problems still unsolved. This PhD thesis deals with MIMO systems inslow and fast varying radio channels. First, the general issues of MIMO systemsare considered. Multiplexing gain and diversity concepts, channel knowledge,coding techniques as well as multiuser access and wideband transmission arediscussed. Next, the channel aspects of MIMO systems are investigated. Thephenomenon of multipath propagation, channel models, variations in the radiochannel and channel estimation are addressed. Then, the author’s research inthe area of slow and fast varying MIMO channels is presented. The followingtheses are formulated and proved:
- The throughput in slow varying radio channels of indoor MIMO systems can besignificantly increased when the locations and the antennas of the access pointare carefully chosen.
- Iterative Channel Estimation (ICE) algorithm allows decreasing the bit errorrate in fast varying radio channels without frequent transmissions of trainingsequences.
The first thesis is founded on thenumerical ray tracing calculations concerning slow varying MIMO channels. It isshown how the locations, the separations and the characteristics of the accesspoint antennas can affect the system throughput. The second thesis is based onthe proposed ICE algorithm for fast varying channels. ICE algorithm enables thechannel estimation simultaneously with the data transmission. When ICE isapplied, the bit error rate can be reduced – in some cases it is more than 50times.
1 MIMO系統基礎
2 MIMO系統的無線通道
3 室內慢變無線通道的傳輸容量
4 快變無線通道估計
附錄 平均誤位元速率的標準差
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