10-10-2012, 02:01 PM
Introduction To Wireless Sensor Networks
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Wireless Sensor Networks
A wireless sensor network is a collection of nodes organized into a cooperative network. Each node consists of processing capability may contain multiple types of memory have an RF transceiver, have a power source (e.g., batteries and solar cells), and accommodate various sensors.
Communication Network
A communication network is composed of nodes, each of which has computing power and can transmit and receive messages over communication links, wireless or cabled.
Basic Network Topologies
Star Topology
Ring Topology
Bus Topology
Tree Topology
Fully Connected Networks
Mesh Networks
Star Topology
All nodes of the star topology are connected to a single hub node. The hub requires greater message handling, routing, and decision-making capabilities than the other nodes. If a communication link is cut, it only affects one node. However, if the hub is incapacitated the network is destroyed.
Ring Topology
In the ring topology all nodes perform the same function and there is no leader node. Messages generally travel around the ring in a single direction.
However, if the ring is cut, all communication is lost.
Bus Topology
In the bus topology, messages are broadcast on the bus to all nodes. Each node checks the destination address in the message header, and processes the messages addressed to it.
Mesh Network
Mesh networks are regularly distributed networks that generally allow transmission only to a node’s nearest neighbors. The nodes in these networks are generally identical.
Network Model for WSN
A wireless sensor network consists of hundreds or thousands of low cost nodes which could either have a fixed location or randomly deployed to monitor the environment. The flowing of data ends at special nodes called base stations (sometimes they are also referred to as sinks).
A base station links the sensor network to another network (like a gateway) to disseminate the data sensed for further processing. Base stations have enhanced capabilities over simple sensor nodes since they must do complex data processing.
Usage of Sensor Networks
Environmental Observation:
Sensor networks can be used to monitor environmental changes. An example could be water pollution detection in a lake that is located near a factory that uses chemical substances. Sensor nodes could be randomly deployed in unknown and hostile areas and relay the exact origin of a pollutant. Other examples include forest fire detection, air pollution and rainfall observation in agriculture.
Healthcare:
Sensors can be used in biomedical applications to improve the quality of the provided care. Sensors are implanted in the human body to monitor medical problems like cancer and help patients maintain their health.
[attachment=35932]
Wireless Sensor Networks
A wireless sensor network is a collection of nodes organized into a cooperative network. Each node consists of processing capability may contain multiple types of memory have an RF transceiver, have a power source (e.g., batteries and solar cells), and accommodate various sensors.
Communication Network
A communication network is composed of nodes, each of which has computing power and can transmit and receive messages over communication links, wireless or cabled.
Basic Network Topologies
Star Topology
Ring Topology
Bus Topology
Tree Topology
Fully Connected Networks
Mesh Networks
Star Topology
All nodes of the star topology are connected to a single hub node. The hub requires greater message handling, routing, and decision-making capabilities than the other nodes. If a communication link is cut, it only affects one node. However, if the hub is incapacitated the network is destroyed.
Ring Topology
In the ring topology all nodes perform the same function and there is no leader node. Messages generally travel around the ring in a single direction.
However, if the ring is cut, all communication is lost.
Bus Topology
In the bus topology, messages are broadcast on the bus to all nodes. Each node checks the destination address in the message header, and processes the messages addressed to it.
Mesh Network
Mesh networks are regularly distributed networks that generally allow transmission only to a node’s nearest neighbors. The nodes in these networks are generally identical.
Network Model for WSN
A wireless sensor network consists of hundreds or thousands of low cost nodes which could either have a fixed location or randomly deployed to monitor the environment. The flowing of data ends at special nodes called base stations (sometimes they are also referred to as sinks).
A base station links the sensor network to another network (like a gateway) to disseminate the data sensed for further processing. Base stations have enhanced capabilities over simple sensor nodes since they must do complex data processing.
Usage of Sensor Networks
Environmental Observation:
Sensor networks can be used to monitor environmental changes. An example could be water pollution detection in a lake that is located near a factory that uses chemical substances. Sensor nodes could be randomly deployed in unknown and hostile areas and relay the exact origin of a pollutant. Other examples include forest fire detection, air pollution and rainfall observation in agriculture.
Healthcare:
Sensors can be used in biomedical applications to improve the quality of the provided care. Sensors are implanted in the human body to monitor medical problems like cancer and help patients maintain their health.