Background:
Real Time Wireless Sensor Networks (RT-WSN) have hard real time packet
delivery requirements. Due to resource constraints of sensors, these networks need to trade-off energy
and latency.
Objective:
In this paper, a routing protocol for RT-WSN named “SPREAD” has been proposed. The
underlying idea is to reserve laxity by assuming tighter packet deadline than actual. This reserved
laxity is used when no deadline-meeting next hop is available.
Objective:
As a result, if due to repeated transmissions, energy of nodes on shortest path is drained out,
then time is still left to route the packet dynamically through other path without missing the deadline.
Results:
Congestion scenarios have been addressed by dynamically assessing 1-hop delays and avoiding
traffic on congested paths.
Conclusion:
Through extensive simulations in Network Simulator NS2, it has been observed that
SPREAD algorithm not only significantly reduces miss ratio as compared to other similar protocols
but also keeps energy consumption under control. It also shows more resilience towards high data
rate and tight deadlines than existing popular protocols.
Hierarchical Scheduling for Real-Time Periodic Tasks in Symmetric Multiprocessing
