REER-H: A Reliable Energy Efficient Routing Protocol for Maritime Intelligent Transportation Systems

The Underwater sensor network (UWSN), also known as Marine Sensor Network (MSN), is gaining increasing attention due to its applications in the monitoring of the marine environment and assisting Marine Intelligent Transportation Systems (MITS). Such systems provide in-vehicle assistance services (i.e., traffic monitoring and driver alerts) by gathering transportation and environmental information. Though very promising, there are several barriers to developing energy-efficient communication protocols for heterogeneous MSN, including selecting optimal routing paths twinned with the lifetime of these sensor nodes along the path, which are restricted due to the limited energy storage capacity. Hereby, the selection of an optimal route path also necessitates harvesting and management of the sensor nodes’ energy. To facilitate this, the current work presents REER-H, a Reliable Energy Efficient Routing protocol with Harvesting for cluster-based MSN capable of multi-source energy harvesting and an incorporated energy management technique. Incorporating three separate layers of the protocol stack, namely, network, MAC, and physical layers, REER-H uses its proposed adaptive scheduling technique to support collision-free data transmission by assigning adaptive time slots based on demand and data load. Also, the proposed integrated energy harvesting and management solves the energy hole problem and enhances the overall network lifetime. In comparison to the existing cooperative and cluster-based energy-efficient routing protocols for underwater maritime communication, the simulated results using Network Simulator-3 (NS3) reveal that the proposed scheme remarkably enhances the overall network performance in terms of packet delivery ratio, throughput, lifetime energy consumption, and end-to-end delay for MSN.

I. Introduction

The massive rise in Intelligent Transportation Systems (ITS) encompasses everything from vehicular transportation and management to in-vehicle assistance services such as traffic monitoring and driver alerts. As a result, the gathering and transportation of information are critical components of all ITS implementations. Most typical ITS systems, however, can only detect a vehicle while it is in a fixed place. With the rapid advancement of human and social development, the importance of marine information technology systems (MITS) and monitoring the marine environment has grown in importance, drawing more and more attention to research and development. The typical maritime monitoring technique, which employs an oceanographic research boat, is expensive and time-consuming, and it has a limited spatial and temporal resolution. The underwater sensor network (UWSN) is a networking paradigm comprised of sensor nodes deployed at different underwater locations that sense, process, and transmit marine environmental data/information to one or more collection points (also called sink) or/and MITS, on the water surface [1]. Optical, acoustic, and radio frequency (RF) wireless carriers can be used for data transmission in UWSN [2]. RF has a low propagation delay in contrast with an acoustic signal. But, RF encounters high absorption which results in a high bit error rate (BER) or high link outage [3], [4]. Besides, Optical waves are affected by scattering, high attenuation, and absorption due to high dense salty water [5]. In contrast to RF and Optical waves, acoustic waves endure low absorption in water and hence regarded as the most preferred medium for long-range underwater communication. However, some of the limiting factors for acoustic signals are – long propagation delay, inter-symbol interference, distance-dependent bandwidth, and large Doppler shift [1], [6].