Table 1.

Signal frequencies and their potential uses [29].

Signal frequency	Potential uses and issues
Low (kHz)	Communications from sensors in soil, pipe-to-pipe data transfer, long-distance data transfer along pipelines. Low power requirements but low data transfer rate.
High (MHz)	Communications from sensors built into pipes, short range data transfer along pipelines, data transfer to surface in chambers. Can communicate more detailed data at higher rates but high power consumption.