Cluster
Head (CH) is also a wireless sensor node, which has more
computational power comparing to all other sensor nodes. These
cluster Heads are responsible for sharing all other sensor nodes
information to the Base Station. The Base Station selects the Cluster
head.
Cluster
Heads broadcasts identifier message to all other wireless sensor
nodes (Adjacent Nodes). The adjacent nodes replies with identifier
acknowledgement to the cluster head.
The
Cluster Head manages the routing table and also the details of all
the nodes in its group. The Cluster Head also maintains details about
other groups Cluster Head and its address with the help of Base
station.
The
normal sensor node in a group maintains a table that contains
information of its Cluster Head address and the common identifier
generated by the Cluster Head.
The
address of the Cluster Head that has already involved in routing has
stored in every packet, it is used for verification by other Cluster
Head.
When
a source node in a need of route to deliver packets to the
destination node, it sends Route Request message to the Cluster Head,
the Cluster Head uses its common identifier to verify the packets.
The
Cluster Head checks whether the destination node is in house, if the
destination node is present under its group, then it sends the packet
directly. If the destination node is not in house then it sends Route
Request message to Base Station, The Base Station intent passes it to
the Cluster Head which manages the Destination node. The Cluster Head
passes then passes packets to the Destination node.
The sensor node under motion makes new route request to the Cluster
Head, then Cluster Head passes the information to the base station.
Source node and destination node under range directly communicates
with each other with the help of adjacent nodes.
If
the source node detects destination node is under its range it sends
route change request to cluster head and it starts sending packets
directly to the destination node(shortest path) through nearby
adjacent nodes.
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