Improving Coverage and Capacity in
Underwater Acoustic Cellular Networks
Amirmansour Nabavinejad *, Samar Shahabi Ghahfarokhi *** Department of Electrical Engineering, Najafabad Branch, Islamic Azad University, Isfahan, Iran** Faculty of Electrical Engineering and Information Technology, Ilmenau University of Technology, Ilmenau,
Germany
dc.nabavinejad@gmail.com, samar.shahabi-ghahfarokhi@tu-ilmenau.de

Abstract— Underwater acoustic communications systems are challenged by the characteristics of acoustic propagation through theunderwater environment. There are a wide range of physical processes that impact underwater acoustic communications and the relative
importance of these processes are different in different environments. Acoustic propagation is characterized by three major factors:
time-varying multipath propagation, low speed of sound and attenuation that increases with signal frequency. Limited bandwidth inthese systems is of paramount obstacles. To overcome this problem the idea of frequency reuse pattern seems to be useful. The key
characteristic of a cellular network is the ability to re-use frequencies to increase both coverage and capacity. One element that
determines frequency reuse is the reuse distance depending on the cell radius and the number of cells per cluster. Analysis of frequency
reuse between adjacent clusters and optimal cell-radius selection criteria has been carried out recently. In other recent woks, theparameters of the cellular networks designing have been calculated based on a rough approximation of the attenuation and propagation
model. In our work, after driving the ratio of signal to interference for underwater acoustic channels with more accuracy, the constraints
for the cell radius are determined. One of the most important results of this contribution is that, for special parameters like bandwidth, it
may be impossible to provide the required signal to interference ratio and bandwidth for the network users. Furthermore, in this paper,
the number of supportable users, per-user bandwidth, and the user capacity for a cellular underwater network are determined.
Keyword— Cell Radius, Frequency Reuse, Signal to Interference Ratio, Underwater Cellular Networks, User Capacity
Amirmansour Nabavinejad (S’12) was born in Isfahan, Iran, in 1978. He received B.S. and M.S. degrees in electrical engineeringfrom Islamic Azad University of Iran, in 2003 and 2006, respectively. Currently he is a lecturer at Mohajer Technical University ofIsfahan and Sepahan Institute of Higher Education, Isfahan, Iran. His research interests are in Digital Communications, Signal
Processing Applications, Information Theory, Coding, Underwater Data Transmission, Acoustic Channel Modeling, Acoustic Imaging
and Cellular Networks.

Samar Shahabi Ghahfarokhi was born in Isfahan, Iran, in 1984. She received the B.S. degree in electrical engineering (Electronics)
from Yazd University, Yazd, Iran, in 2007. Currently, she is working toward the M.S. degree in the Faculty of Electrical Engineering
and Information Technology, Ilmenau University of Technology, Ilmenau, Germany. Her research interests include Telecommunication
Systems, Information Theory, Data Communication Networks, Cellular Networks, Digital Signal Processing and Digital ImageProcessing.