Optimization of channel capacity in magnetic communication systems subjected to total power constraint

This paper considers formulation and optimization of channel capacity of magnetic communication systems through various types of mediums, subjected to an overall power constraint. Following a parametric investigation of the induced electromotive force, the optimal operating frequency is derived. Maximization of channel capacity is obtained by a modified “Water filling” algorithm with upper-frequency limit, which provides the optimized power allocation along the spectrum. The results are compared to constant power spectral densities with optimized bandwidth, symmetric or asymmetric around the optimal frequency. It is shown that for a given system, the bandwidth and its spectral location, are the dominant parameters which determine the channel capacity, whereas the exact shape of the power distribution within the bandwidth is less significant. Also, an upper-frequency limit is required to prevent overestimation of capacity in dielectric media conditions and short range. Resonance circuits are compared to circuits without capacitors, showing similar results regarding capacity but with narrower bandwidth for the resonance circuits.