多輸入多輸出（MIMO）正交頻分複用（OFDM）技術在多路徑衰落的寬帶無線通道上擁有傳輸高數據速率，但是其對時間和頻率同步誤差非常敏感，導致信道間干擾（ICI）產生。這種現象會導致多輸入多輸出的正交頻分複用系統中的服務質量（QoS）的性能下降。
該研究提出了一種有效率的多目標設計方法，利用適當選擇預編碼矩陣，通過最大化訊號相對於干擾和雜訊比之值來優化服務質量性能以及最小化能量消耗來達到最佳的能量效率在多輸入多輸出的正交頻分複用的系統上。多目標預編碼設計被轉換為等效線性矩陣不等式（LMIs）的多目標最佳化問題（MOP），利用提出的線性矩陣不等式限制多目標演化算法（MOEA）可以保證凸度和總體收斂。由於多目標演化算法可以提供一組Pareto最佳解，我們可以在多輸入多輸出的正交頻分複用系統中選擇一種可以達到最小均方誤差（MMSE）的解決方案作為選擇預編碼設計的方法。最後，模擬結果說明設計過程也同時證實多輸入多輸出的正交頻分複用系統提出的多目標預編碼方法的性能。

Multi-input multi-output (MIMO) orthogonal frequency division multiplexing (OFDM) techniques can allow the transmission of high data rates over broadband wireless channels subject to multipath fading, but they are however very sensitive to time and frequency synchronization errors giving rise to inter-channel interference (ICI). This phenomenon causes the performance degradation of the quality of service (QoS) in MIMO OFDM systems.
In this study, we propose an efficient multiobjective design method by maximizing the SINR value for optimal QoS performance and minimizing power consumption for optimal power efficiency of MIMO OFDM systems simultaneously through a proper selection of a precoding scheme. The multiobjective precoding design is transformed to an equivalent linear matrix inequalities (LMIs)-constrained multiobjective optimization problem (MOP), which could be easily solved by a proposed LMIs-constrained multiobjective evolution algorithm (MOEA) to guarantee the convexity and global convergence. Since the MOEA can provide a set of Pareto optimal solutions, one solution which can also achieve the minimum mean square error (MMSE) equalization is selected as the preferable precoding design in MIMO OFDM systems. Finally, simulation examples are given to illustrate the design procedure and to confirm the performance of the proposed multiobjective precoding scheme of MIMO OFDM systems.

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