THE SOFTWARE APPROACHES FOR SOLVING HYDROACOUSTIC COMMUNICATION PROBLEMS IN MARINE INTERNET OF THINGS SYSTEMS

Abstract

When several hydroacoustic modems operate simultaneously in an area of mutual coverage, collisions
of data packets received from several sources may occur, which leads to the loss of some or all
information. With the increase in the number of simultaneously operating hydroacoustic modems, physical
layer algorithms do not provide stable data transmission and the likelihood of collisions increases,
which makes the operation of modems ineffective or even impossible. To ensure effective operation in a
hydroacoustic signal propagation environment and to reduce or eliminate collisions during the exchange
and delivery of data between two modems that do not have the ability to operate synchronously,
as well as to reduce the access time to the signal propagation environment, methods of the medium access
control layer are required using link layer protocols. Typically, this problem is solved using code
separation of hydroacoustic channels. Modems communicate as if at different frequencies, which does
not create collisions, this allows subscribers of the underwater network to communicate in a point-topoint
format, or in multicast mode, that is, everyone separately, however, in case it is necessary to make
a transmission over the network , this option is no longer suitable, since network transmission involves
working on the basis of “broadcast” messages. In practical use, it is convenient to place these protocols
into a software development environment (framework) for specific user applications for solving network
communication problems. Such a framework is usually called a software framework; it allows for user
modification of the network algorithms available in the framework, as well as the inclusion of new network
hydroacoustic communication algorithms by the user. To build a predictive model, the DACAP, TLohi,
Flooding and ICRP protocols were used in the work. The algorithms were implemented in Erlang.
The paper presents algorithms for implementing these protocols. A comparative analysis of network
operation with and without protocols is provided. Efficiency and speed of work were assessed. Recommendations
for further development of the software framework are given