Terrestrial vs. Underwater Sensor Networks: Key Differences

This article outlines the key differences between terrestrial and underwater sensor networks, detailing their design considerations, communication methods, and deployment challenges.

Terrestrial Sensor Networks

Terrestrial sensor networks operate on land, utilizing air as the primary communication channel.

These networks typically consist of transmitters and receivers that use electromagnetic radio waves to transmit data, voice, or other information. They are a common and well-understood technology.

Underwater Sensor Networks

Underwater sensor networks are specifically designed for operation in aquatic environments. They rely on water as the communication channel.

These networks also consist of transmitters and receivers but employ different communication methods due to the properties of water. Electromagnetic radio waves, optical waves, and acoustic waves can be used, each with its own limitations.

• Electromagnetic (EM) Waves: EM waves can propagate through conductive seawater at very low frequencies (30-300 Hz) over longer distances. However, this requires large antennas and high power, making it less practical for many underwater applications.
• Optical Waves: Optical waves experience less attenuation compared to EM waves in water. However, they are susceptible to scattering loss and require precise, narrow laser beams for data transmission. This makes them suitable primarily for short-range communication.
• Acoustic Waves: Due to the limitations of EM and optical waves, acoustic waves are the most common method for communication in underwater sensor networks.

Key Differences Between Terrestrial and Underwater Sensor Networks

The following table summarizes the key distinctions between terrestrial and underwater sensor networks:

Detailed Breakdown of Differences

• Size and Cost: Because air is readily available, Terrestrial networks are generally cheaper to deploy than Underwater Networks
• Node cost: Terrestrial sensor nodes are typically inexpensive due to their smaller size and less demanding environmental requirements. Underwater sensor nodes, however, are considerably more expensive due to the need for robust protection against the harsh underwater environment. The underwater transceiver hardware needs to be housed in a pressure-resistant enclosure, increasing cost.
• Deployment: Terrestrial sensor networks are often deployed densely due to their lower cost. Underwater deployments are typically sparser due to the higher cost per node and the inherent challenges of underwater deployment.
• Power: Acoustic communication in underwater networks requires significantly more power than terrestrial communication. This is due to the greater distances involved and the need for more complex signal processing at the receiver to overcome challenging channel conditions. Underwater networks need more energy consumption due to the complex channel, and therefore require batteries with higher capacity.
• Memory: Terrestrial sensor nodes typically have limited storage capacity. Underwater sensor nodes often require more data caching due to intermittent channel availability and the potential for communication delays.