Determination of path attenuation values for hardware emulation of tactical radio networks

Modern tactical networks play an important role in success on the battlefield. Unfortunately, performance evaluation of tactical networks is cumbersome because of the scale and complexity of the underlying systems involved and the cost of deploying large numbers of systems and personnel. Simulation of the tactical network system is sound in theory; but in practice it is extremely difficult to build a suitable model for a large-scale tactical network and hence simulation often fails to approximate the system with good fidelity. An alternative is to emulate the tactical channels carrying signals from real radios. This can conveniently be implemented in a laboratory environment using one or more multiport radio frequency (RF) hubs with variable attenuation on each port to be able to emulate the radio path loss between any two radios. The problem in this emulation approach is the determination of the appropriate port attenuation to match the multi-dimensional link losses (signal attenuations) between multiple radios of a real tactical network. A tactical network with N radios has N(N-1)/2 network links which are characterised by their respective link losses. The emulator network with N radios has N connections between the multiport hub and N radios of the network. The problem is therefore selecting the set of N attenuation values of the N port hub to match N(N-1)/2 link losses of tactical networks. This is a constraint satisfaction problem (CSP). We describe an algorithm based on Freuder´s solution synthesis to find the solution to the CSP.