Multi Critical Event Monitoring in WSN using Sleep Scheduling

Abstract

A wireless sensor network (WSN) is a wireless
network using sensors to cooperatively monitor
physical or environmental conditions. The project
focuses on critical event monitoring in wireless sensor
networks. When a critical event is detected, the
alarm packet should be broadcast to the entire network
as soon as possible. Broadcasting delay is an important
issue for the application of the event monitoring. To
minimize the broadcasting delay, it is needed to
minimize the time wasted for waiting during the
broadcasting. Here a novel sleep scheduling method is
proposed to reduce the delay of alarm broadcasting
from any sensor node in WSNs. As the alarm message
may be originated by any possible node, there are two
phases for the alarm broadcasting. First, when a node
detects a critical event, it originates an alarm message
and quickly transmits it to a center node along a
predetermined path with a level-by-level offset way.
Next, it is immediately broadcast by the center node
along another path without collision. The upper
bound of the broadcasting delay is only 3D + 2L,
where D is the maximum hop of nodes to the center
node, L is the length of sleeping duty cycle.