期刊名称:International Journal of Antennas and Propagation
印刷版ISSN:1687-5869
电子版ISSN:1687-5877
出版年度:2014
卷号:2014
DOI:10.1155/2014/318421
出版社:Hindawi Publishing Corporation
摘要:The significant attenuation experienced by electromagnetic
waves in sea water is the main reason why acoustic
waves are generally preferred in underwater communication.
Nevertheless, acoustic waves have various drawbacks. For example,
they are negatively affected by factors such as mechanical
noise, slow propagation speed, and, particularly, low bandwidth,
which leads to digital links at a lower bit rate. However, in short-range
links, these problems can be overcome by reconsidering
the use of electric current communications. For instance, data
collected by remote-control vehicles in offshore oil and gas and
renewable energy plants can be transmitted at distances of
even 1 m or less. This study uses previous frequency response
measurements taken in deep water to explore the capacity of
a short-range electromagnetic underwater channel. Because of
water movement, the nonstatic position of the vehicle when
the transmission occurs means that the channel is regarded as
randomly time-variant. A statistical model is proposed and the
ergodic capacity is calculated for a 7 MHz bandwidth channel at
distances ranging from 0.5 m to 5 m as well as for different
values of transmitter power. The results of this study reflect
capacity values of tens of kbps at distances of approximately
5 m to several Mbps at distances of less than 1.5 m.