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Esrt: Event-to-Sink Reliable Transport in Wireless Sensor Networks[Sankarasubramaniam et al, Acm mobiHoc 2003]
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tarix | 05.03.2018 | ölçüsü | 549 b. | | #30125 |
| Bu səhifədəki naviqasiya:
- Motivation A sink is only interested in the collective information from a number of source nodes and not in individual sensor reports
- To configure the reporting rate f
- Five characteristic regions
- If pending congestion is detected CN bit is set in event reports
- Stability of ESRT ESRT converges to OOR from any of four initial states {(NC,LR), (NC,HR), (C,HR), (C,LR)}
- Simulation Setup Ns-2 simulator
- From (NC,LR) From (NC,HR)
- Power savings from (NC,HR)
- Questions Definition of reliability as number of received packets
- Is it reasonable assumption that a sink is capable of broadcasting to all the source nodes
- What if the density of source nodes is too low to meet the required reliability with fast reporting
ESRT: Event-to-Sink Reliable Transport in Wireless Sensor Networks[Sankarasubramaniam et. al, ACM MobiHoc 2003]
Motivation A sink is only interested in the collective information from a number of source nodes and not in individual sensor reports Event-to-sink communication - Different from traditional notion of end-to-end communication
Energy-efficient
Problem Statement To configure the reporting rate f of source nodes so as to achieve the required event detection reliability R at the sink with minimum resource utilization Also resolve congestion
Typical Behavior at a Sink
Five characteristic regions
Congestion status is required at the sink to determine the network state Based on expectation of buffer overflow at sensor nodes If pending congestion is detected CN bit is set in event reports
ESRT Actions
ESRT State Diagram
Stability of ESRT ESRT converges to OOR from any of four initial states {(NC,LR), (NC,HR), (C,HR), (C,LR)} From (NC,HR), ESRT stays in the state until converges to OOR
Simulation Setup 200 sensor nodes 100m x 100m area 40m transmission range 65 packets IFQ 10 sec decision interval (τ)
From (NC,LR)
From (NC,HR)
(C,HR) to (NC,HR) then OOR
(C,LR) to (NC,LR) then OOR
Power savings from (NC,HR)
Conclusion - Self-configuration
- Energy awareness
- Uses minimum energy while achieving required reliability
- Congestion control
- Collective identification
- Biased implementation
Questions Definition of reliability as number of received packets? Is ESRT congestion detection accurate and reliable? - ESRT action heavily depends on the congestion state
- What if the congestion reports are inconsistent due to partial congestion or underlying path oscillation?
- What is the effect of inaccurate congestion state detection on ESRT?
Is it reasonable assumption that a sink is capable of broadcasting to all the source nodes ? what if R is higher than the peak point?
- Out of band?
- If in-band, how to deal with congestion?
What if the density of source nodes is too low to meet the required reliability with fast reporting?
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