Stationary vs. Mobile WSN: Key Differences Explained

This article breaks down the differences between stationary and mobile Wireless Sensor Networks (WSNs). Let’s dive in!

What is a WSN?

A Wireless Sensor Network (WSN) is made up of:

• End sensor nodes: These gather data from the environment.
• Routing nodes: These forward data towards the destination.
• Base station (or data collector/sink node/gateway): This is where the collected data is received and processed.

A good WSN should be scalable (able to handle more nodes) and secure, ensuring reliable data delivery.

WSNs can be categorized in many ways, including by network type, clustering method, communication protocol, application, and coverage area. Two primary categories are stationary WSNs and mobile WSNs.

Stationary WSN

A stationary WSN is a wireless sensor network where the sensor nodes remain in a fixed location.

Advantages of Stationary WSNs:

• Easy to Deploy and Maintain: Because the nodes don’t move, setup and upkeep are simpler.
• Optimized Placement: Nodes can be precisely positioned for optimal coverage and density, allowing more nodes to be placed in a smaller area.

Disadvantages of Stationary WSNs:

• Static Topology: The network’s structure doesn’t automatically adapt to changes.
• Vulnerable to Node Failure: If a node fails, it can create a break in the network, leading to data loss or network partition.

Mobile WSN

A mobile WSN consists of sensor nodes that can move. It’s sometimes referred to as a MANET (Mobile Ad-hoc Network). These networks are infrastructure-less and consist of mobile devices (nodes) with the following characteristics:

• Self-configuring: Automatically adjust to network changes.
• Self-healing: Can recover from node failures.
• Self-optimizing: Improve performance on their own.
• Self-protecting: Can defend against security threats.

Mobile sensor nodes collect data as they move. When they get close to a sink node, they transmit the collected information. In some scenarios, the sink node itself is mobile and collects data from stationary sensor nodes.

The figure above displays a mobile WSN architecture where the sensor nodes and sink are immobile. In such cases, mobile data collectors (also known as data mules) collect data from stationary sensor nodes and deliver it to the data sink. This data collection/delivery method is known as data muling.

Types of Mobile WSNs based on Environment:

• Underwater Mobile WSN: Sensor nodes collect data beneath the sea or water’s surface.
• Terrestrial Mobile WSN: Sensor nodes are deployed on land for applications like wildlife monitoring, surveillance, and object tracking.
• Aerial Mobile WSN: Nodes fly in the air to collect data.