Wireless Sensor Network (WSN) Basics, Architecture, and Security

This article covers Wireless Sensor Network (WSN) basics, WSN features, WSN architecture, and security considerations. It touches upon WSN monitoring devices and applications for various wireless networks.

The primary function of a Wireless Sensor Network (WSN) is to collect information using sensors and transmit it to a designated location. To achieve this, the deployed communication system requires efficient and reliable networking protocols. The network must be scalable and, importantly, secure. A popular technology underpinning many WSNs is Zigbee. Zigbee is a low-power wireless personal area network technology.

Figure: Typical WSN network architecture

As depicted above, a typical WSN network architecture comprises sensor nodes, routing nodes, and a base station.

WSNs have gained considerable popularity due to the availability of low-cost sensors and the extended lifespan of power supply batteries. They are also easily deployed in diverse environments. A WSN can be considered a variant of an Ad-hoc network. In a standard Ad-hoc network, multiple nodes can transmit packets to the base station. However, WSNs necessitate collaboration between different types of sensor nodes.

Here are some key features of Wireless Sensor Networks:

• Sensor nodes are generally stationary.
• They can be readily deployed in challenging environments.
• Communication is data-centric rather than address-centric. Router decisions are based on the data itself, not the address. This allows for actions like dropping, compressing, or prioritizing packets based on their content.
• Communication utilizes short packet sizes to minimize overhead.
• Many wireless sensor devices employ energy harvesting techniques to extend battery life. These techniques enable WSN sensors to generate energy from ambient sources and store or use it to recharge the battery or capacitor.

WSN Architecture

As previously mentioned, the WSN architecture consists of three main components: distributed sensor nodes, sink nodes (Base station or Gateway), and software.

Each sensor node typically has a single omnidirectional antenna, a transceiver, a power supply, and an embedded DSP (Digital Signal Processor).

The gateway is positioned at the edge of the monitored area. It facilitates the connection between the micro-sensor network and the outside world, such as the internet or other WSNs. A sensor network may contain thousands of sensors distributed randomly and densely, perhaps 10-20 per square meter.

The availability of flash memories and energy-efficient batteries contributes to improved wireless sensor networks. Algorithms based on wireless standards manage collision and congestion within the network. WSNs are classified based on factors like network type, clustering type, communication method, protocol, application, and coverage.

Due to their wireless nature, these systems are inherently susceptible to security risks. Various measures are implemented to ensure safety within the wireless sensor network.

WSN Monitor Software

WSN monitor software provides a user interface for real-time sensor measurements. It connects to the WSN Open API Base Station or Gateway using API messages. For further details, see this link: https://www.tkt.cs.tut.fi/research/gwg/wsn_monitor.html