為了提升行動通訊系統在上行方向的高可靠低延遲傳輸 (URLLC) 的系統容量，使用多重使用者多輸入多輸出 (MU-MIMO) 和免競爭 (contention-free) 配置授權 (configured grant) 技術能夠利用傳送端和接收端彼此的多根天線提升頻譜使用效率，並免去使用者因請求排程所花費的時間以及競爭造成的傳輸失敗可能性，且接收端使用了逼零連續消除 (ZF-SIC) 演算法來確保高可靠度，這篇論文中提出了在此架構下的多使用者訊號解碼順序、使用者分組和排程機制。

解碼順序考慮了 ZF-SIC 的運作原理，依照訊號雜訊比 (SNR) 的大小來決定順序從而強化了傳輸的可靠度。

分組機制的目標是使用最少的時頻資源就能滿足所有使用者的 URLLC 需求，因此每一組共用相同資源的使用者都要能發揮最大資源共享效益，我們使用矩陣表示多個使用者訊號並將每一組的挑選問題轉換成非等方性正交普洛克路斯忒斯分析 (anisotropic orthogonal Procrustes analysis, AOPA) 問題，此外還納入對解碼順序的考量設計了強化版的分組機制。

排程機制的目標則是盡可能將任一個使用者在最差情況下從出現傳輸需求到存取傳輸資源的時間間隔縮到最短。

模擬結果顯示我們提出的整套機制相較於現有的方法能夠大幅提升系統容量並大幅減少使用的資源量和傳輸延遲，並且是在確保所有使用者都滿足 URLLC 要求的前提下。

To improve the capacity and performance of mobile networks for envisioned ultra-reliable low-latency communication (URLLC) scenarios in the uplink direction, we propose a set of methods. To maximize the capacity of URLLC and achieve high spectral efficiency with reasonable decoding complexity, we focus on contention-free configured-grant transmission with multi-user multiple-input multiple-output (MU-MIMO) capability and zero-forcing successive interference cancellation (ZF-SIC) decoder. Each of our methods consists of three parts--decoding order determination, user grouping, and group scheduling. The decoding order is determined based on the signal to noise ratio (SNR) for reliability enhancement. The user grouping attempts to minimize the turnaround time by exploiting orthogonal Procrustes analysis (OPA) or anisotropic orthogonal Procrustes analysis (AOPA). The group scheduling greedily minimizes the response time. Simulation results validate that our methods outperform existing methods in terms of capacity, the number of resource units, and latency.

Abstract------------------------------------------- i
中文摘要------------------------------------------- ii
誌謝辭-------------------------------------------- iii
Contents ----------------------------------------- iv
List of Figures ---------------------------------- vii
1 Introduction ------------------------------------- 1
2 Preliminary -------------------------------------- 3
2.1 URLLC ------------------------------------------- 3
2.2 Latency components ------------------------------ 5
2.3 Configured-grant (CG) --------------------------- 7
3 Related Work ------------------------------------- 9
3.1 Contention-based CG scheduling ----------------- 10
3.2 Contention-free CG scheduling ------------------ 11
3.3 Improvement by multiplexing technologies ------- 12
4 System Model ------------------------------------ 13
4.1 Resource unit ---------------------------------- 14
4.2 Channel model ---------------------------------- 16
4.3 ZF-SIC ----------------------------------------- 17
4.4 Turnaround time and response time -------------- 20
5 Decoding Order ---------------------------------- 22
6 User Grouping ----------------------------------- 25
6.1 Select top users ------------------------------- 28
6.1.1 AOPA ------------------------------------------ 28
6.1.2 OPA ------------------------------------------- 29
6.2 Verification and effective rates calculation --- 30
6.3 Enhanced user selection ------------------------ 32
6.4 Complexity ------------------------------------- 35
7 Group Scheduling -------------------------------- 36
8 Performance Evaluation -------------------------- 41
8.1 Simulation settings ---------------------------- 41
8.2 Simulation results ----------------------------- 43
8.2.1 Number of resource units ---------------------- 44
8.2.2 Turnaround time ------------------------------- 46
8.2.3 Reliability satisfaction ---------------------- 47
8.2.4 Response time --------------------------------- 49
8.2.5 Throughput ------------------------------------ 51
9 Conclusion -------------------------------------- 53
A Inter-cell Interference ------------------------- 54
Reference ----------------------------------------- 55

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