Abstract:
In wireless sensor networks (WSNs), energy
is a very scarce resource and has to be managed
wisely in order to extend the life of the sensors.
Therefore, to be energy-efficient, this paper is
presented as hybrid protocol for MAC layer in
Wireless Sensor Networks (WSNs). It combines
contention and schedule-based methods. Time
slot assignment is designed by semi-distributed
manner. A base station is considered as a master
only for its one-hop children because nodes are
also memory (buffer)-constrained ones in real
world. When a base station sends token to its
neighboring nodes all the way through the
largest-hop nodes and token is sent back to the
base station, this may cause the overflow of
buffer or the time slot assignment table may be
damaged during token is passing through all the
nodes. To avoid this problem, time slot
assignment is only considered as the two-hop
neighbors from each parent.