Wireless Channels in Shipboard Environments: Challenges and Opportunities

Abstract

_ For most of the twentieth century, the vast majority of studies of wireless in shipboard environments focused on electromagnetic compatibility between the numerous antennas that are installed on the ship’s superstructure and the high power transmitters associated with them, often referred to as the topside environment. With the advent of short-range wireless data and sensor networks in the late 1990’s, researchers began to assess the nature of wireless propagation below decks and the potential role of wireless personal communications and wireless personal, local area, and sensor networks in shipboard environments. As expected, researchers found that the confined spaces below decks, with their numerous reflecting surfaces and bulkheads, severely attenuate and distort wireless signals and greatly complicate wireless system planning. Moreover, the propagation environment is highly variable and greatly affected by the opening and closing of watertight doors and loading or unloading of cargo and stores. The greatest challenges, however, are that the nature of wireless propagation aboard a given vessel is usually unknown until after the vessel is built and measurements can be performed, and current ship design guidelines and rulebooks offer no guidance concerning design for wireless system compatibility. Here, we review progress in measurement and modeling of shipboard wireless propagation environments over the past twenty-five years with particular emphasis on their applicability to emerging 3GPP/5G and NextG wireless systems. We conclude that although past efforts offer useful insights concerning the physics of wireless propagation aboard ship, they are largely site-specific or anecdotal. As a result, their outcomes cannot yet cast in a form that can usefully contribute to either simulation or design of shipboard wireless networks. Further, although advances in wireless test and measurement technology have somewhat eased the task of conducting link-level measurements and assessing signal attenuation and distortion, such information is insufficient to support design of modern shipboard wireless networks. Accordingly, it seems likely that network performance data obtained from live networks will be as or perhaps even more important as link-level data obtained using lab-grade test and measurement equipment going forward. In response, we propose a modelling framework for shipboard wireless propagation that captures the role of propagation and channel models in simulation and design across the development life cycle (standards development, system development, and system deployment) and thereby overcomes many of the limitations of past work. We further propose a measurement framework for shipboard wireless propagation that captures the respective roles of the two approaches and suggests how such data can be usefully pooled or combined.