Analysis of the periodic impulsive noise asynchronous with the mains in indoor PLC channels

Indoor broadband power-line noise is composed of three main terms: impulsive components, narrowband interferences and background noise. Impulsive components can be classified into three groups according to their behavior with respect to the mains cycle: periodic synchronous with the mains, periodic asynchronous with the mains and aperiodic. Periodic asynchronous terms are the most interesting ones because they have significant spectral components in the band used by broadband power-line communication systems. This paper presents a detailed analysis of this noise component in the frequency band up to 25 MHz. By means of a methodology that combines both frequency and time domain techniques, repetition rates and pulse waveforms are obtained even in scenarios in which the remaining noise terms have significant level.