Radio frequency propagation model and fading of wireless signal at 2.4 GHz in an underground coal mine
A Patri, DS Nimaje
Wireless sensor networks and wireless communication systems have
become indispensable in underground mines. Wireless sensor networks are
being used for better real-time data acquisition from ground monitoring
devices, gas sensors, and mining equipment, whereas wireless communication
systems are needed for locating and communicating with workers.
Conventional methods like wireline communication have proved to be
ineffective in the event of mine hazards such as roof falls, fires etc. Before
implementation of any wireless system, the variable path loss indices for
different workplaces should be determined. This helps in better signal
reception and sensor node localization, and also improves the method by
which miners carrying the wireless devices are tracked. This paper
proposes a novel method for determining the parameters of a suitable
radio propagation model, which is illustrated with the results of a practical
experiment carried out in an underground coal mine in southern India. The
path loss indices, along with other essential parameters for accurate
localization, have been determined using the XBee modules and ZigBee
protocol at 2.4 GHz frequency.
Keywords: WSN, RSSI, path loss index, miner localization, underground coal mining,
ZigBee.