循環脈衝正交分頻多工實現未來5G之非同步多用戶上行鏈路傳輸

Abstract

實現非同步多用戶上行鏈路傳輸對於下一代無線網絡 (5G) 非常重要且必要，因為它應該要能夠滿足像是超可靠的低延遲通信 (URLLC) 和大規模機器類型通信 (mMTC) 這類的要求。在放寬的同步條件下，被廣泛應用於第四代行動通訊的正交分頻多工技術，由於它的高子頻帶外散射，所以容易影響到鄰近頻帶的用戶。5G候選波形之一的循環脈衝形預編碼正交分頻多工，透過預編碼矩陣的設計它可以同時擁有低子頻帶外散射以及低峰軍功率比的優點。本論文將會在異步多用戶上行鏈路循環脈衝形預編碼正交分頻多工的系統下，陳述頻域等化器的架構以及其最佳化問題的設計。模擬結果顯示了透過所提出來的頻域等化器，循環脈衝形預編碼正交分頻多工的錯誤率性能優於應用濾波器技術的正交分頻多工和應用窗口重疊並添加技術的正交分頻多工。因此循環脈衝形預編碼正交分頻多工系統將會成為第五代行動通訊非同步傳輸場景中最具發展潛力的技術之一。

Enabling asynchronous multiuser uplink transmission is important and necessary for the next generation of wireless networks (5G) since it has to be able to meet the requirements for some scenarios, such as ultra-reliable low-latency communications (URLLC), and massive machine type communications (mMTC). In relaxed synchronization conditions, orthogonal frequency division multiplexing (OFDM) system, which is widely used in the fourth generation of the wireless network (4G), is easy to interfere adjacent users due to high out-of-subband emission (OSBE). Circularly pulse-shaped precoding orthogonal frequency division multiplexing (CPS-OFDM) system, a new waveform for 5G candidates, possesses the advantages of both low OSBE and low peak-to-average power ratio (PAPR) through precoding matrix design. In this thesis, the structure of frequency-domain equalizer (FDE) and its optimization problem design are proposed under the asynchronous multiuser uplink CPS-OFDM system. Simulation results show the BER performance of CPS-OFDM outperforms that of Filtered-OFDM (f-OFDM) and Weighted Overlap and Add based OFDM (WOLA-OFDM) by the proposed FDE. Thus, CPS-OFDM system will be one of the most developmental potentials in future 5G asynchronous transmission scenarios.