Home Page

What is rModem?

Reconfigurable modem (rModem) is a software-defined underwater acoustic modem. It is based around Matlab, Simulink, which provides a unified simulation and rapid prototyping environment. Simulation code, which is flexible and modular, can be converted with little effort into real-time code that runs on a DSP board. The rModem hardware provides high processing gain and large memory, therefore relaxing the coding requirements and minimizing engineering work.

Why rModem?

rModem is designed to simplify the experimental studies of candidate signal processing algorithms and network protocols for underwater acoustic systems.

Experimental work constitutes an important part of research on acoustic communications because there are no widely accepted mathematical channel models that can be used for simulation (as it is the case in radio communications). Current research relies on point-to-point experiments that are performed by recording experimental data and processing it off-line. Such an approach suffices for testing of basic signal processing algorithms, but not for network protocols, or communication methods that rely on real-time feedback from the receiver. For network testing, off-the-shelf modems are sometimes used; however, these modems have hard-coded parameters that cannot be changed, which limits the freedom in experimenting with different network designs.

rModem eliminates hard constraints, and allows in-water experimentation in real, or near real time. It includes all layers of a network architecture, and provides the possibility of cross layer optimization. Different communication methods can be tested in the same environment, within a short time span, simply by reprogramming the modem.

The primary purpose of the rModem is to support experimental research, by providing a testing and evaluation platform for newly designed communication methods. It is not optimized for low power consumption or small size; instead, it allows freedom of experimentation and simplicity of programming in software environment familiar to most students, researchers and engineers.