Underwater Wireless Sensor Communications in the 2.4 GHz ISM Frequency Band
Lloret, J. L.
; Sendra, S. S.
; Ardid, M. A.
Rodrigues, J. R.
Sensors Vol. 12, Nº 4, pp. 4237 - 4264, March, 2012.
ISSN (print): 1424-3210
ISSN (online): 1424-8220
Journal Impact Factor: 2,033 (in 2015)
Digital Object Identifier: 10.3390/s120404237
One of the main problems in underwater communications is the available low data rate due to the use of low frequencies. Moreover, there are many problems inherent to the medium such as reflections, refraction, energy dispersion, etc., that greatly degrade communication between devices. In some cases, wireless sensors must be placed quite close to each other in order to take more accurate measurements from the water while having high communication bandwidth. In these cases, while most researchers focus their efforts on increasing the data rate for low frequencies, we propose the use of 2.4 GHz ISM frequency band in these special cases. In this paper, we show our wireless sensor node deployment and its performance obtained from a real scenario and measures taken for different frequencies, modulations and data transfer rates. The performed tests show the maximum distance between sensors, the number of lost packets and the average round trip time. Based on our measurements, we provide some experimental models of underwater communication using EM waves at 2.4 GHz ISM frequency band in fresh water. Finally, we compare our communication system proposal with the existent systems. Although our proposal provides short communication distances, it provides high data transfer rates. It can be used for precision monitoring such as contaminated ecosystems or to communicate devices at high depth.