Periodic noise in very low frequency power-line communications

Abstract

Very low frequency (VLF) power line communications (PLC) presently has widespread use in AMR/AMI deployments and may also be useful for smart grid applications, largely due to its excellent propagative properties. However, noise within the VLF band is more energetic than at higher frequencies and without effective mitigation algorithms degrades channel capacity, possibly to the point of making the band impractical. Recent work has demonstrated that PLC noise in the low frequency band (LF) and above is effectively modeled as a cyclostationary random process. We present measurements of actual power line noise and argue that the cyclostationary model is unnecessarily restrictive and that VLF PLC channel may be modeled as having a non-trivial wide-sense periodic component. We demonstrate the preponderance of periodic noise in this band by means of constrained covariance estimation from power line noise measurements. This has important ramifications for receiver design and when employed appropriately will increase the post-processed SNR, making VLF PLC a more attractive prospect for smart grid communications.

Periyodik Gürültü Tipleri ve Yapısal Özellikleri

“…Düşük frekanslı gürültü, bir boyutlu sinyallerde genel olarak 10 Hz ila 1000 Hz aralığında kabul edilmektedir [27,29,30]. Düşük frekans dalga grafiği Şekil-3.a'da görülmektedir.…”

Local Utility Power Line Communications in the 3–500 kHz Band: Channel Impairments, Noise, and Standards

“…More recently, studies targeted specifically for NB-PLC have shown that periodic noise and cyclostationary noise are the dominant components of the additive noise in these systems [3], [14]- [16]. A typical time-domain noise trace and a spectrogram of noise samples collected in the field at medium and low voltage sites with some possible sources is given in Fig.…”

“…In addition to the cyclostationary noise, [16] shows that in the very low frequency (VLF), below 10 kHz, there is an additional wide-sense periodic noise component. Presently, the VLF range is extensively used by AMR providers.…”

“…Presently, the VLF range is extensively used by AMR providers. This periodic structure is exploited in [16] to filter out this component and increase the post-processing SNR of these systems.…”

A serial IFFT precoding scheme to mitigate the periodic noise in OFDM system

“…However, sometimes non-Gaussian noise can also be the dominated influence factor or the extra influence factor in an OFDM system. For example, in typical PLC-OFDM system, periodic impulsive noise is one of the most devastating factors severely limiting the communication performance [6]. In the real-time OFDM system, the sampling clock noise, behaving as periodic sinusoidal noise, also has certain influence on the system performance [7].…”