電力線通訊系統以配電網路來傳送資訊，不需架設基礎設備，具有低成本且隨插即用的特色，將在未來智慧電網中扮演重要的角色。此系統通道特性包含阻抗、衰減以及多種雜訊干擾，其中以多路徑衰減和隨機脈衝雜訊的影響最為嚴重，因此探討及改善此二者之傷害為研究電力線通訊系統的主要議題。
本論文研究依據寬頻電力線G.hn (Gigabit Home Networking)標準規格，此標準使用的錯誤更正編解碼技術為低密度奇偶檢查碼(LDPC)。一般使用改錯碼都是考量在固定背景雜訊功率的通道下，若通道存在額外的雜訊(如脈衝雜訊)影響，即會降低系統解碼的能力。本論文將模擬分析偵測隨機脈衝雜訊的不同方法，同時整合(理想)通道等化器以降低多路徑衰減的影響，並將上述處理所造成的雜訊功率變化視為有意義的資訊，帶入LDPC軟式解碼器所需要的對數似然比(Log-Likelihood Ratio, LLR)計算中，藉以改善解碼可靠度，使系統性能提升。

Power line communication (PLC) system can exchange information over the existing electrical grid without much extra implementation cost. Such system will play an important role in the future Smart Grid. The channel characteristic of PLC system includes variant load impedances, high attenuation and a variety of noise interference. Among them, the multipath fading and random impulse noise (IN) are the most serious impairments in the system. Therefore, the development of novel technologies to reduce the impact of these two is the main research topic for the PLC systems.
The study of this thesis is based on the G.hn (Gigabit Home Networking) standard for broadband PLC systems. This standard adopts the low-density-parity-check (LDPC) for error-correction. In general, the use of error-correcting code is under the assumption of a fixed background noise channel. However, if there is additional variant noise (e.g. impulse noise), the decoding ability may be reduced. This thesis first analyzes different detection schemes for the random IN by simulations. Then, the system combined the (ideal) channel equalizer to combat multipath channels. Finally, we propose a novel system design, which modifies the log-likelihood ratio (LLR) calculation of the LDPC decoder with the information of noise-power change due to the process of IN detection and equalizer, to improve the system performance.

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