MAC Protocols The Influence of Communication Patterns on the MAC Protocol Design

CSMA Protocol Send when no-one else is sending Wait until air is clear

Hidden Node Problem Nodes A and C can’t hear each other Collision happens at the receiver Carrier detection happens at the sender A B C

Collision Avoidance (MACA) AB C Ready to send AB C Clear to send AB C Data

Simulation Results goodput msg/node/s Network protocol performance msglen= input msg/node/s CSMA MACA

Research Charter Look at MAC protocol performance from a communication pattern point of view

Sink Routing Sink routing gives directionality Directionality lessens effect of hidden node problem

Directionality Experiment Grid network Experiment 1: random communication Experiment 2: directed communication All other parameters are equal

Simulation Results goodput msg/s input msg/s Direction experiment CSMA directed MACA directed CSMA random MACA random

Conclusions Communication patterns do have an influence on the choice and design of the MAC layer protocol If we design a MAC protocol for WSNs, we should take communication patterns into account

Next Steps Implement communication patterns in simulator Implement energy model and more realistic radio propagation model Test and optimize MAC protocols based on energy usage Implement protocol on EYES node