Characteristics of Power-Line Channels in Cargo Ships

The broadband PLC in cargo ships is a long-awaited technology. However the characteristics of power-line channels in the cargo ships have not been studied yet. The most unique point of the channels is that power-line cables used in most Asian cargo ships are shielded. In order to characterize the channel and investigate a suitable PLC system to the cargo ships, some parameters were measured in three typical ships. The parameters were the transfer functions (LCTR, LTR and TTR), LCL and stationary noise spectrum. From these measurements, (1) the required dynamic range of receivers, (2) average attenuation at distribution boards, (3) phase coupling loss and (4) average LCL values were derived in this paper. Since the cables are shielded and the hull provides the good ground, the usage of the common-mode transmission in addition to the conventional differential-mode, which is referred to as a dual-mode transmission system, is also proposed. Therefore the measured parameters above were included the common-mode and mode-conversion properties. As the evidence to support our proposal, some results in which the LCTR values were superior to the TTR values are shown.