VLF-band Power Line Channel Sounding David W. Rieken, Zhixi Li, and Chris Fleck Advanced Systems Research & Development Aclara Technologies, LLC St. Louis, MO, USA
Summary VLF band (1-9 KHz) • Not regulated by the FCC • Legacy AMI systems (e.g. TWACS, Turtle) • Good signal propagation properties? • Signal frequency is higher than mains, but still low enough to permit long distance comms • Presents unique challenges to PLC because of low data rate and significant mains interference Overview • VLF-band channel sounding • Experimental setup • Survey results
Analysis: convolution with sounding signal Spreading signal so that it is orthogonal to mains makes detection in low SNR channels easy.
Conclusions Any VLF-band PLC system must • Accommodate a wide range of link strengths • Leverage higher concentrator data rates than endpoint data rates • Maximize system throughput, rather than instantaneous data rate Analysis shortcomings • Sampling rate offset • Time-varying channel IPR