cross layer application specific wsn design over ss trees l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Cross-Layer Application-Specific WSN Design over SS-Trees PowerPoint Presentation
Download Presentation
Cross-Layer Application-Specific WSN Design over SS-Trees

Loading in 2 Seconds...

play fullscreen
1 / 33

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


  • 102 Views
  • Uploaded on

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

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Cross-Layer Application-Specific WSN Design over SS-Trees' - cameo


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
outline
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
background introduction
Background Introduction
  • Wide-area surveillance WSN applications
    • expected lifetime
    • limited battery supply
  • Energy Efficiency is paramount
  • Adaptive sleep schedules to minimize energy lost
background introduction4
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
background introduction5
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
sleep scheduling issues
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
sleep scheduling issues7
Sleep Scheduling Issues
  • Using coordinated sleep scheduling
    • Realize the benefits:
      • reduced overhearing
      • reduced packet collision
      • simplified topology
    • Without sacrifice:
      • network connectivity
      • sensing capabilities
ss tree concept9
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)
ss tree concept issues to be considered
SS-Tree Concept--issues to be considered

Gaps appearing in between

the active period of adjacent SS-Tree

ss tree concept issues to be considered11
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

ss tree concept issues to be considered12
SS-Tree Concept--issues to be considered

Drawback: timer-driven

Data cannot be simultaneously

Gathered from all SS-Trees

ss tree operational stages14
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
ss tree operational stages15
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 other’s sleep schedule
ss tree computation17
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.
ss tree operational specifics sleep scheduling
SS-Tree Operational Specifics & Sleep Scheduling
  • Major task – determine an optimal sleep schedule that maximizes energy efficiency
  • Short active period -> high transmission latency
  • Longer active period -> 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
ss tree operational specifics sleep scheduling24
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
ss tree operational specifics sleep scheduling26
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
ss tree operational specifics sleep scheduling27
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

ss tree operational specifics sleep scheduling31
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

conclusion and future work
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?