Cross-Layer Application-Specific WSN Design over SS-Trees - PowerPoint PPT Presentation

1 / 33
About This Presentation
Title:

Cross-Layer Application-Specific WSN Design over SS-Trees

Description:

-Prepared by Amy Outline Background Introduction Sleep Scheduling Issues & the SS-Tree Concept SS-Tree Operational Stages SS-Tree Computation SS-Tree Operational ... – PowerPoint PPT presentation

Number of Views:58
Avg rating:3.0/5.0
Slides: 34
Provided by: JINW5
Category:

less

Transcript and Presenter's Notes

Title: Cross-Layer Application-Specific WSN Design over SS-Trees


1
Cross-Layer Application-Specific WSN Design over
SS-Trees
  • -Prepared by Amy

2
Outline
  • Background Introduction
  • Sleep Scheduling Issues the SS-Tree Concept
  • SS-Tree Operational Stages
  • SS-Tree Computation
  • SS-Tree Operational Specifics Sleep Scheduling
  • Conclusions and Future Work

3
Background Introduction
  • Wide-area surveillance WSN applications
  • expected lifetime
  • limited battery supply
  • Energy Efficiency is paramount
  • Adaptive sleep schedules to minimize energy lost

4
Background Introduction
  • Sleep scheduling
  • shorten the time radio transceiver engaged in
    idle listening
  • Good impact
  • reduced overhearing
  • Ensuing problem
  • link table entries expire prematurely
  • control and data packet compete for resources
  • real-time data reporting function reduced

5
Background Introduction
  • Ultimate Design Goal
  • Balance
  • sensing requirements
  • end-to-end data communication overhead
  • network control effectiveness
  • With energy efficiency
  • Through a cross-layer sleep scheduling scheme

6
Sleep Scheduling Issues
  • Not recommended
  • Random sleep scheduling
  • detrimental effect on network connectivity and
    topology control efficiency
  • Global sleep scheduling
  • network-wide communication blackout
  • Groups of leaf nodes sleep scheduling
  • non-leaf nodes depleting battery reserves sooner

7
Sleep Scheduling Issues
  • Using coordinated sleep scheduling
  • Realize the benefits
  • reduced overhearing
  • reduced packet collision
  • simplified topology
  • Without sacrifice
  • network connectivity
  • sensing capabilities

8
SS-Tree Concept
9
SS-Tree Concept
  • Advantages
  • Avoid overburdening any set of nodes from being
    the sole virtual backbone
  • Increase monitoring sensitivity (greater event
    reporting windows) without altering communication
    duty cycle(reporting frequencies)

10
SS-Tree Concept--issues to be considered
Gaps appearing in between the active period of
adjacent SS-Tree
11
SS-Tree Concept--issues to be considered
-- Blackout duration -- Sleep period --
number of mutually adjacent SS-Trees -- Active
period
Number of distinct live path To guarantee 100
real-time event reporting capability
Not feasible due to limited nodal density And
high SS-Tree computation complexity Not necessary
to approach real-time Intuition suggests the
number of SS-Tree Should less than the average
nodal degree
12
SS-Tree Concept--issues to be considered
Drawback timer-driven Data cannot be
simultaneously Gathered from all SS-Trees
13
SS-Tree Operational Stages
14
SS-Tree Operational Stages
  • Network Initialization
  • gather network connectivity information,
  • compute the SS-Trees
  • disseminate the sleep schedules
  • Sleep
  • shut down the radio transceiver
  • processor and sensing unit remain active
  • Hibernation
  • Shutting down all hardware components
  • except for a tiny low-power wakeup timer

15
SS-Tree Operational Stages
  • Active
  • all data reporting
  • network maintenance tasks are performed
  • Failure Recovery
  • data sink repair or reconstruct SS-Trees
  • Neighborhood Update
  • neighboring nodes exchange local information
  • for each others sleep schedule

16
SS-Tree Computation
17
SS-Tree Computation
  • A greedy depth-first approach
  • From the bottom-up on a branch-by-branch basis
  • Proceeds in a number of iterations
  • In each iteration an end-to-end minimum cost path
    is appended to one of the SS-Trees.

18
SS-Tree Computation
19
SS-Tree Computation
20
SS-Tree Computation
21
SS-Tree Computation
22
SS-Tree Operational Specifics Sleep Scheduling
  • Major task determine an optimal sleep schedule
    that maximizes energy efficiency
  • Short active period -gt high transmission latency
  • Longer active period -gt increase sleep time
    between two consecutive active periods
  • Determine an upper bound of active period
  • balance low communication duty cycle
  • monitoring sensitivity
  • end-to-end packet transmissions

23
SS-Tree Operational Specifics Sleep Scheduling
Network Layer Routing
24
SS-Tree Operational Specifics Sleep Scheduling
  • Some flexible strategies in manipulating
    application requirements
  • Compact query formats
  • shrink packet size by formatting data types
  • reduce hop-by-hop transmission time
  • Aggressive data aggregation
  • duplicate suppression
  • reduce unnecessary packet exchange
  • Hop-by-hop ACK in MAC layer
  • instead of end-to end ACK in transport layer
  • reduce energy expenditure

25
SS-Tree Operational Specifics Sleep Scheduling
26
SS-Tree Operational Specifics Sleep Scheduling
  • Medium Access Control
  • Prefer single-channel unslotted CSMA
  • simplicity
  • greater scalability
  • looser time synchronization requirements
  • Bypass the RTS/CTS handshake
  • long end-to-end propagation delay

27
SS-Tree Operational Specifics Sleep Scheduling
Timing components constituting a single active
period
Round-trip time recorded for node I on its
respective SS-Tree
28
SS-Tree Operational Specifics Sleep Scheduling
29
SS-Tree Operational Specifics Sleep Scheduling
30
SS-Tree Operational Specifics Sleep Scheduling
31
SS-Tree Operational Specifics Sleep Scheduling
IACK works better in reducing the time when the
size of C/D packet is comparable to that of EACK
32
Conclusion and Future Work
  • Following issues will be explored
  • For a given random topology, what is the maximum
    number of SS-Trees that can be constructed to
    minimize the number of shared nodes?
  • For a given number of nodes, what is the optimal
    method of deployment that ensures 100 coverage
    of the subject area while maximizing the number
    of available SS-Trees with minimum shared nodes?
  • What are the suitable neighborhood discovery and
    failure recovery strategies for the SS-Tree
    design?

33
The End
Write a Comment
User Comments (0)
About PowerShow.com