an energy-efficient and low-latency routing protocol for wireless sensor networks antonio g....
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An Energy-Efficient and Low-Latency Routing Protocol for Wireless Sensor Networks
Antonio G. Ruzzelli, Richard Tynan and G.M.P. O’HareAdaptive Information Cluster, Smart Media Institute
Department of Computer ScienceUniversity College Dublin
Proceedings of the 2005 Systems Communications (ICW’05)Proceedings of the 2005 Systems Communications (ICW’05)
Chien-Ku Lai
Outline
Introduction Related Work Scheduling in Merlin Experimentation and Results Conclusions and Future Work
Introduction- Wireless Sensor Networks (WSNs)
Components:One or more base-stationsMany sensor nodes
Constraints on sensor nodes:EnergyStorage capacitiesData processing
Introduction- Wireless Sensor Networks (WSNs) (cont.)
Applications: Ecosystem monitoring Emergency operation Intelligence detection of ambient conditions Intrusion detection Localization of objects or animals Medical monitoring Structural monitoring Surveillance
Introduction- Wireless Sensor Networks (WSNs) (cont.)
Major form of energy wastage: Idle listeningCollisionTransmissions overheadOverhearing
Introduction- about this paper
MERLIN is presentedMac Energy efficient, Routing and Localizatio
n INtegratedCombination of TDMA and CSMA
Related Work
SMACTMAC DMAC
SMAC
Uses a coordinated adaptive sleeping mechanism
The main drawbacks:Latency
RTS/CTS mechanism
The increase of energy consumption when some nodes join the network
TMAC
An improvement to the SMAC protocol Uses an overhearing mechanism RTS/CTS collisions are very high Latency is still present
DMAC
Incorporates a data gathering tree to reduce the latency
The main drawback: It is suitable only for unidirectional
communication flow to a single gateway
Scheduling in Merlin
Scheduling in Merlin
The purpose of MERLIN scheduling is to allocate time-zone slots
Nodes in the same time-zone use the same slot to transmit
The timing of the slots prevents most collisions
Scheduling in Merlin
V-table
X-table
Scheduling in Merlin- V-scheduling
1 2 3 4 5 6 7 8 9
Gateway
Scheduling in Merlin- X-scheduling
1 2 3 4 5 6 7 8 9
Gateway
Experimentation and Results
1. Network setup time2. Network lifetime3. Latency of messages
Simulation environment
OmNet++ EYES WSNs testbed Number slot /frame = 4 DataRate = 115200 bits/sec Contention period = 30ms DataSize = 16+8 Bytes (data + 3 bytes pre
amble + starting code)
Simulation environment (cont.)
Nodes with the same colors are in the same zone (same hop count number)
Network setup time
Network lifetime
Latency of messages (1/4)
X-scheduling
V-scheduling
Latency of messages (2/4)
X-scheduling
V-scheduling
Latency of messages (3/4)
X-scheduling
V-scheduling
Latency of messages (4/4)
X-scheduling
V-scheduling
Latency of messages- Comparison
Conclusions and Future Work
Conclusions
The absence of handshake mechanisms like RTS/CTS can considerably reduce the latency of messages
Idle listening is reduced by the TDMA approach
CSMA technique increases the scalability
Conclusions (cont.)
X scheduling is suitable for applications in which latency is
a tighter constraint V-scheduling
performs better than the X-scheduling in terms of percentage of collisions and network lifetime
Future Work
Perform more experimentation to compare MERLIN scheduling with other WSN protocols
Clarify the impact of our design decisions with mobile nodes
Questions?
Thank you.Thank you.
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