Time-invariant characteristics of naval power-line channels

In this paper, time-invariant characteristics of power-line communications (PLC) channels in ships are evidenced. A multiport channel model derived from transmission-line theory is used to investigate the frequency response under various loading conditions. The time-invariant power-line channel in ships is mainly due to the low impedance of parallel cables attached to the switchboard acting as an electrical node. Based on a statistical analysis, the time variance of the channel response is more sensitive to the number of branches than the length of branches. The evaluation of the number of branches that guarantees the time-invariant behavior of a power-line channel in ships has been carried out using nonlinear least mean square estimation. As a result, the time-invariant PLC channels of the multibranch power network in ships mitigate the channel estimation for coherent demodulation in a communication system.