An Approach to Construct Weighted Minimum Spanning Tree in Wireless Sensor Networks - Software Engineering, Artificial Intelligence, Networking and Parallel/Distributed Computing - page 73

basic duties- to report events and deliver messages to the sink node. Therefore, it
will choose the nearest parent node which has more energy than itself, and in this
case, parent 1 . The following algorithm is also discussed in [17].
Proposed SWST algorithm for each node u:
E(u)=remaining energy,
status(u)=either active, sleeping or comatose,
D(u)=set of distances between the current node and the sender nodes,
PE(u)=set of energy levels of the parent nodes,
P(u)=set of parent node IDs,
FP(u)=final parent node ID,
tr(u)=transmission range,
TEL=Threshold Energy Level.
In this study, one sink node is assumed. The sink node starts the TC by
broadcasting a Hello message. Hello messages include three items which are the
sender node ID, sender node's energy level and sender node's transmission power
level in order to enable the determination of the RSSI (if each node's maximum
transmission range is fixed, then one can remove this portion of the message and
decrease the message length thereby saving energy).
The following algorithm description is also found in [17].
1) Initialization:
P(u)=Ø, FP(u)= Ø, PE(u)= Ø, D(u)= Ø, status(u)=comatose, tr(u)=maximum
transmission range.
2) Parent Discovery:
Starts Parent Discovery timeout.
Starts Hello message listening timeout.
Hello message listening timeout expires.
If does not receive any Hello message
status(u)=comatose;-
Else status(u)=active;
update P(u): upon receiving Hello message from a sender node v,
P(u)=P(u) U {v};
update PE(u): PE(u)=PE(u) U {E(v)};
update D(u): D(u)=D(u) U {distance(u, v)};
End if.
Parent Discovery timeout expires.
Broadcast Hello message to the children nodes.
3) Parent Selection:
Starts Parent Selection timeout.
Calculate max(PE(u))
If max(PE(u)) > E(u) && E(u) < TEL