| Abstract: | 本計畫擬針對一協同多中繼點使用多天線之網路系統於中繼點遭受前向與後向多 輸入多輸出頻率選擇性衰落通道環境，研究放大而前向中繼預編碼器之最佳化設計。特 別地，我們將利用完整通道資訊及有限整體中繼功率與接收功率限制以設計最佳中繼預 編碼器。另外，我們將分析所得到最佳化設計後之中繼網路性能表現。文獻上，大部分 之最佳化中繼預編碼器大都是設計針對當下傳送的區塊，並建立在一個固定且無區塊間 干擾之前向與後向通道矩陣的情況，例如常假設是單輸入單輸出或多輸入多輸出之平坦 性衰落通道矩陣。不同於過去文獻的研究，在考慮一多中繼網路實際遭受前向與後向多 輸入多輸出頻率選擇性衰落通道的情況下，本計畫將探討利用我們最新研究成果設計最 佳中繼預編碼器。本計畫的研究目標說明如下。 我們擬先於各個中繼點與目的點分別導入最近所提出之基於斜投影架構等化與偵 測機制之新型線性區塊等化器與非線性區塊內決策回授等化器。更明確地說，每一個中 繼點與目的點將利用我們所建立之斜投影架構對一特定區塊完整消除其區塊間干擾，然 後再分別使用線性與非線方式來等化區塊內符碼間干擾。透過建立在各個中繼點與目的 點之等化架構，在有限整體中繼功率與接收功率限制下，中繼預編碼器及最佳區塊(欲 被等化與偵測)的選擇將被設計達成中繼網路之最低位元錯誤率及分別滿足區塊內迫零 與最小均方誤差等化準則。我們將先利用蒙地卡羅電腦模擬方式估計出上述設計之最佳 區塊，然後再理論性分析提出之最佳化中繼網路的性能表現。在給定中繼點與目的點相 關通道資訊、中繼網路相關系統參數與有限整體中繼功率及接收限制功率，我們將進一 步推導分別滿足區塊內迫零與最小均方誤差等化準則且達成最低化中繼網路位元錯誤 率之直接決定上述最佳區塊演算法。另外，透過理論性的推演，我們也將對所建構的設 計建立決定次最佳區塊演算法。最後，根據上述的研究結果，我們將透過電腦模擬以驗 證決定最佳與次最佳區塊演算法的合理性與強韌性。 本計畫提案之研究成果預計結合我們設計之新型等化與偵測機制建立一套針對一 協同多中繼網路於多輸入多輸出頻率選擇性衰落通道環境下之完整最佳化設計理論。
This project plan investigates the amplify-and-forward (AF) relay precoder optimization for a cooperative multiple relays network scenario in which the relays are equipped with multiple antennas and suffered the backward and forward MIMO frequency-selective fading channels. Particularly, the optimum relay precoders are devised with full channel state information (CSI), subject to limited total relay power and received power constraints. Additionally, the overall performance of the pursued optimum relay network is theoretically analyzed. In literature most optimized relay precoders are designed with respect to the instant (transmitted) block for combating the given fixed forward and backward channel matrices with no inter-block interference (IBI), e.g., SISO or MIMO flat-fading channels are usually assumed. Contrary to previous studies, this project plan applies our recent research results to optimize the relay precoders for a cooperative multiple relays network undergoing forward and backward MIMO frequency-selective fading channels. The targets of this project plan are described as follows. First, the relays and the destination are employed with the novel linear intrablock equalizer and non-linear intrablock decision feedback equalizer, respectively, based on the recently proposed oblique-projection framework and detection scheme. Specifically, in each relay and destination the intrablock inter-symbol interference (ISI) equalization is performed in linear and non-linear fashion, respectively, after completely eliminating IBI for a particular block via the oblique projection framework. With such equalizing schemes, the relay precoders and the selection of the optimum (particular) blocks (to be equalized and detected) are devised for intrablock zero-forcing (ZF) and minimum mean-squared-error (MMSE) equalization criteria, respectively, such that the bit-error-rate (BER) of the relay network is minimized under limited total relay power and received constrained-power. Monte Carlo simulations are applied to determining the optimum blocks in above designs, and then, the performances of the proposed optimized relay network are theoretically analyzed. Given the available CSI at relays and destination, the associated parameters of the relay network, and the limited total relay power and received constrained-power, separate algorithms are derived for directly determining the above optimum blocks in the relays and destination so that the BER of the relay network is minimum for intrablock ZF and MMSE equalization criteria. Moreover, theoretical derivations are provided to build the sub-optimum algorithms for our designs. Finally, computer simulations are conducted to justify the derivations and robustness of the above algorithms. Results of this project plan are expected to construct a complete theory with our novel equalization and detection schemes for optimizing a cooperative multiple relays network under the MIMO frequency-selective fading channels. |
