ARQ Designs for Space-Time Coded Systems

在多重收發天線系統中，利用多輸入多輸出的 通道可以獲得更高的資料速率及多樣性增益。然 而，在需要高可靠度之系統中，採用ARQ 有其必 要性。因此，在本研究中，我們研究如何利用不同 的重傳方式，結合多層次編碼設計達到高速率及高 可靠度的資料傳輸。 在本研究中，我們考慮BLAST 系統之準靜態衰 減通道中結合多層次編碼設計以及混合四進制相 移鍵控與二進制相移鍵控的重傳機制。我們給予模 擬結果並且跟先前設計之以空時區塊碼為基礎之 ARQ 作一個比較。此外，我們將在BLAST 系統之準 靜態衰減通道中，研究將傳統上複雜度不同之混合 自動重傳機制結合多層次編碼設計，由模擬之結果 探討系統效能，並且也與以時空區塊碼為基礎之 ARQ 作一個比較。而且我們也利用混合ARQ 將BLAST 系統中不同層次之訊息給予不同之保護，且與傳統 之ARQ 作一個效能上的比較。It is possible to achieve communications with high data rates and diversity gains through exploiting the multiple-input multiple-output (MIMO) channel. However, for applications of high reliability requirement, automatic repeat request (ARQ) is usually needed. In this research, we study several different ARQ schemes for the layered space-time coding system. We consider the ARQ scheme which uses a combination of QPSK and BPSK transmissions together with layered space-time codes over quasi-static fading channels. Through simulation results, we compare this scheme with a similar ARQ scheme over the Alamouti space-time block coding (STBC). Furthermore, we consider applying ARQ schemes of different complexity with layered space-time codes over the quasi-static fading channels. In addition, we consider a hybrid ARQ scheme which provides different protection to messages of distinct layers in the BLAST system. Comparison among the various ARQ schemes for the layered space-time coding system is given based on the simulation results