在本論文中，我們研究向量擾動技術於多輸入多輸出通訊。本論文最主要貢
獻有三方面。首先，在多使用者之多輸入多輸出系統裡我們提出雙模式向量擾動
技術，雙模式向量擾動技術可以減少球面編碼次數。其次，在點對點多輸入多輸
出系統裡我們提出向量交換技術且把向量交換技術和向量擾動技術結合於多使
用者的多輸入多輸出系統裡使傳輸能量功率減少，提出一個可以同時搜尋最佳擾
動向量和交換向量的樹狀搜尋方法。第三，把提出的向量擾動及交換技術運用於
相互關聯通道之有限回饋系統，提出的向量擾動及交換技術可以抵抗通道相互關
聯之劣化，預先定義的查尋表被提出來為了搜尋最佳的擾動向量和交換向量。最
後，我們利用數值模擬的方法來證實這三個提出來系統的效能。

In this thesis, we have studied the vector perturbation precoding techniques for MIMO
communications [1]. The major contributions of this thesis are in three folds. First, we
propose dual modes vector perturbation transmitter based multiuser MIMO systems.
The dual modes vector perturbaion transmitter can reduce the number of sphere encoder
[1] calls. Second, we propose the vector permutation system for point-to-point MIMO
systems and combine the vector permutation with vector perturbation for multi-user
MIMO systems with multiple antenna receiver to further reduce the energy of tranmitted
signal of vector perturbation system. A searching algorithm of optimal perturbation
vector and permutation vector simultaneously by tree search is also proposed. Third,
the proposed vector permutation and perturbation is applied to limited feedback system
in correlated channel. The proposed vector permutation and perturbation system can
combat the degradation of channel correlation. The predefining lookup table is proposed
for searching the optimal perturbation and permutation vectors. Finally, we verify the
performance of three proposed systems by means of numerical simulations.

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