What is Wireless Sensor Network (WSN)? Architecture and its Applications

Wireless Sensor Network (WSN)

WSN can generally be described as a network of nodes that cooperatively sense and control the environment, enabling interaction between persons or computers and the surrounding environment.

WSN consist of distributed autonomous of sensors that cooperatively monitor chemical (e.g. Dissolved Oxygen, pH, Small organic compounds, and large organic compounds), biological (e.g. Microorganism) and physical or environmental conditions such as temperature, pressure, sound, motion, and vibration at a location.

WSNs now days usually includes;

  1. Sensor nodes
  2. Actuator nodes
  3. Gateways and clients (sink)

 

What is Sensor?

Sensor is a device that is capable of detecting changes. Sensor is a transducer, measuring physical phenomenon e.g. heat, light, motion, vibration and sound.

What is sensor network?

Sensor network consist a number of sensor nodes (motes). Nodes are deployed either inside or near to a parameter being sensed.

Sensor node is a basic unit of sensor network, containing;

  1. Sensor
  2. Memory (data acquisition, communicating with sensor, processing etc.)
  3. Transceiver (connection to the outer world, e.g. Sensor node and data acquisition)
  4. Power supply (battery).

WSNs ARCHITECTURE

Architecture, refers to the physical arrangement of different sensor nodes (motes) in a wireless sensor network.

There are two common WSN architecture;

  1. Flat architecture
  2. Hierarchical architecture.

 

Flat architecture

In flat architecture all nodes are treated equally. When node needs to send data, it may find a route consisting of several hops to the sink.

Hierarchical architecture

In hierarchical routing protocols, clusters are created and a head node is assigned to each cluster. These nodes as the leaders of their groups have some responsibilities like collecting and aggregating the data from their respective clusters and transmitting the aggregated data to the BS.

STANDARDS OF WIRELESS SENSOR NETWORK (WSNs)

Examples of standards of wireless sensor network are;

  1. IEEE 802.15.4
  2. ZigBee
  3. 6LoWPAN (IPv6 over low power WPAN)

 

APPLICATIONS OF WIRELESS SENSOR NETWORK (WSNs)

  1. Intelligent buildings (or bridges);  monitor mechanical stress after earthquakes
  2. Smart agriculture; using a combination of sensor such as humidity, temperature, pH detects the risk of frost, possible plant diseases.
  3. Smart cities; Noise pollution, garbage level, traffic and parking level
  4. Industrial control;  fault detection
  5. Body area networks for sports and healthcare; Insulin pumps, Foot drop implants.


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