基於QR分解之無線通訊多輸入多輸出偵測

Abstract

多重輸入多重輸出技術為一個提供較高頻寬效能的有效解決方案。然而，多輸入多輸出偵測之缺失起因於天線間的干擾效應及ill-condition問題。為了將天線間的干擾效應降低，我們提出基於QR技術的有效率基因演算結合可靠的初始值，三角矩陣型式與多樣式突變率。為了對抗ill-condition問題，我們研究於有限回授系統下，基於SV選擇法來尋找預編碼以最佳化多重輸入多重輸出偵測效能。為達選擇法之最佳化，吾人提出QR選擇法是依據有效率分解法與較大對角元素邊界值所推導出來的並用於對抗ill-condition問題並將此發展於切換系統與多模預編碼系統。新提出方法利用SVD與GMD可預先決定傳輸模式下來找尋預編碼。這些方法主要優勢是具備較低計算複雜度與較佳偵測效能。此提出方法不僅適用於單使用者多輸入多輸出系統，並且適用於多使用者操作多重輸入多重輸出系統以協調預編碼。效能分析與模擬驗證所提出QR方法可以使用較低的計算複雜度亦能達到現存方法的效能。

Multiple input multiple output (MIMO) technology is a promising solution to provide higher spectral efficiency. However, the impairment of MIMO detection (MD) is caused by inter-antenna interference (IAI) and ill-conditioned problem. To better mitigate IAI, effective GA-MD associated with QR-based techniques exploit good initial setting, triangular form and diversity-based mutation (DM) are proposed. To prevent the ill-conditioned problem, we study conventional SV-based section criterion to find the precoder to optimize the performance of MD in the limited feedback systems. To optimize the section criterion, the QR-based selection criteria depending on effective decomposition and a larger bound among diagonal entries are proposed to resist the problem developed in switching and multi-mode precoding systems. The new criteria exploiting SVD and GMD perform a predetermined mode to find the precoder. The main benefits of the proposed criteria are their lower computational complexity and better detection performance. The proposed criteria are suitable not only for single user MIMO (SU-MIMO) system, but also for multi-user MIMO (MU-MIMO) system with the cooperative precoding. Performance analysis and computer simulations confirm that the proposed QR-based schemes attain the performance of existing schemes with a significantly lower complexity level.