智慧工廠802.11ax高密度網路之資源分配與存取點設置

On Access Point Deployment and Resource Allocation for 802.11ax-based Dense WiFi in Smart Factories

鍾承翰(Chen-Han Chung)

指導教授 ： 蔡志宏

國立臺灣大學/電機資訊學院/電信工程學研究所/碩士(2022年)

https://doi.org/10.6342/NTU202203234

摘要

最近幾年來，興建智慧工廠成為自動化生產的一個重要方向。為了使得資料傳輸與控制信號可以有效且可靠，很多網路問題的解決使利用IEEE 802.11ax (WiFi 6)的技術來實現。在802.11ax的網路架構下可以解決許多關於資訊傳遞以及兩台或多台裝置之間的溝通的網路問題。
在此篇論文中，我們提出了一個分散式的演算法，此演算法之設計是為了解決資源分配以及試著最佳化系統效能。在分散式演算法的前提下，每一台AP都有自己運行的演算法來達成系統的最佳化而非受到中央系統下指令控制。每台AP要分配給底下裝置的資源分別有頻道與傳輸能量。另外，我們設定了兩種模式: 一為資源分配最佳化模式，另一為公平性模式。此兩種模式在我們回合制的運行過程中會依據整體效能來評估下一回合應該使用何種模式。當系統效能有過門檻時會選擇資源分配最佳化模式，而當系統效能不佳時會選擇公平性模式。資源分配模式會週期性地改善整體資源分配，而公平性模式會把整體系統的公平性提升。
最後，我們所提出的演算法會透過模擬來呈現及分析。我們設定了四種環境，沒有障礙物、有對稱性的障礙物、有不對稱性的障礙物以及最後會依據智慧工廠的一些特性來模擬真實的環境。本篇所提出的演算法會拿來與隨機佈建法與循序漸進佈建法比較，並在模擬結束時分析各個環境下各個演算法的各種表現狀況。

關鍵字

IEEE 802.11ax ； 無限存取點 ； 服務品質 ； 資源分配 ； 擁擠網路環境 ； 分散式系統 ； 智慧工廠

並列摘要

In recent years, the smart factory has become an important direction for manufacturing automation. In order to transmit data and control signals reliably within a smart factory, many network solutions have emerged and IEEE 802.11ax based WiFi has been found to be a promising information and communication technology for such Cyber-Physical System (CPS).
This thesis proposed a distributed auto-configuration and resource allocation algorithm in which each AP can operate on its own, instead of relying on a control center giving all instructions to APs. The main contribution of this algorithm is its capability to optimally allocate key resources of APs, including frequency channel, transmitting power, AP placement location. Furthermore, it allows two different modes to cope with two types of network conditions: one case with QoS qualified for most APs, and the case in which QoS levels are not satisfied for certain APs. For the first mode, the algorithm can periodically improve network throughput and reducing interference; while for the second mode, QoS fairness can be adjusted to a better level.
In the final result, the proposed system is demonstrated via simulation and it is shown that cross AP interferences are greatly reduced and the total throughput is improved under a dense WiFi network, comparing to legacy network designs. The resource allocation approach of the proposed system is also found promising for various types of smart factory environments.

並列關鍵字

IEEE 802.11ax ； access point ； quality of service ； resource allocation ； dense WiFi ； distributed system ； smart factory

參考文獻

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