電力線網路系統之網路品質量測研究

Abstract

本篇論文中，針對HomePlug AV規格下的電力線通訊設備進行網路路徑特徵的量測研究，經由對其規格標準與廠商實作上的特色進行分析，提出於電力線通訊上量測網路特徵所需處理的議題，並由處理此議題發展出新的量測工具HTMProbe，能夠量測出在此種多重速率網路系統中，切換至最高傳輸模式下所需的最小量測速率，並同時量測出此網路的Link Capacity和Available Bandwidth，接著在不受干擾的測試環境下進行實驗，驗證電力線通訊此種多重速率網路系統量測上的議題，再透過利用現存的網路特徵評估工具進行實測，研究這些工具在此種網路量測上的侷限，並利用實驗驗證我們工具的可用性。 電力線通訊利用電力線路為傳輸媒介，其線路上存在多種未知的電器干擾，而此種干擾對於電力線通訊的影響程度將左右其效能，因此本篇論文利用實驗環境對多種電器進行實測，並從干擾的程度對於下載速率的影響進行分類，用以探討不同種類干擾與不同位置設置對於電力線通訊效能的影響，並實測電磁干擾濾波器對於電力線通訊效能的改善程度，發現其對於穩定電力線通訊有顯著的效果。In this thesis, we investigate the network path characteristic of power line communication (PLC) under HomePlug AV standard by experiments. First, we analyze the feature of PLC according to the specification of the HomePlug and the real products which are implemented by different factories. Based on the feature, the measurement issue in the kind of multi-rate network system is need to be solved. For the issue, HTMProbe is proposed to probe the minimum sending rate in highest transmission mode and at the same time probe the link capacity and available bandwidth. Then in the experiment environment, we use the existing well-known measurement tools to probe the link capacity of PLC, and find their limitations. We test HTMProbe in our testbed and find that is provides good estimates of the link capacity, available bandwidth and the minimum sending rate to overcome the limitations. Using power line as the media to transmit, it will be interfered by several electronic devices and obstruct the performance of network. We test several electronic devices, and classify them by the level of interference according to the download rate, and investigate the effect of different level of interference and the relative position between electronic devices and PLC devices. Final, we test the electromagnetic interference filter in the experiment environment to improve the PLC performance.