具區碼記憶之渦輪多輸入天線系統

Abstract

在多重收發天線系統中，利用多輸入多輸出 (Multi-input/Multi-output, MIMO) 的通道可以獲得更高的資料速率及多樣性增益。有很多系統架構被設計來運用在多重收發天線系統之中，從最早的多層次時空編碼設計到最近的渦輪多層次編碼設計 (Turbo-BLAST) 以及低密度同位校正碼 (LDPC) 之多重天線結構等等。而在白色高斯雜訊 (AWGN) 的通道系統中，我們已知可藉由結合區碼記憶 (Interblock Memory) 的設計來增進迴旋碼 (Convolutional Codes) 或渦輪碼 (Turbo Codes) 的效能表現。因此，在本論文中，我們研究如何將區碼記憶和不同的多重天線架構結合來達到增進系統效能的目標。 首先，我們利用一個編碼率為三分之二的迴旋編碼器和一個二階層的區碼記憶體跟渦輪多層次編碼設計作結合，並將之應用在區塊衰減通道 (Block fading channel) 和快速衰減通道 (Fast-fading channel) 之中。我們提供模擬結果並可從中看到此一架構的改進處。接著，我們提出另一套結合區碼記憶和低密度同位校正碼的多重天線系統架構，並將之應用於快速衰減通道上，而我們將在模擬結果之中看出這種架構的優點所在。

We can get higher data rates and diversity gains by exploiting the multiple-input multiple-output (MIMO) channel. There are many system configurations designed for MIMO channel, from the outset layered space-time (LST) coding to the recent Turbo-BLAST configuration and LDPC structure for MIMO model, etc. It is also known that a convolutional or turbo coding scheme can be improved by serially concatenating an interblock memory for AWGN channel. Hence, in this thesis, we use the combination of different MIMO system model with the interblock memory to achieve better performance. We first combine a 2/3 code rate convolutional encoder and 2-level interblock memory with Turbo-BLAST system over block fading channel and fast-fading channel. The simulation results reveal the improvement of our proposed method. Second, another combing method for LDPC structure over MIMO fast-fading channel was proposed, and the advantage of the proposed scheme is demonstrated by simulation.