Cross-Layer Optimization for Wireless Sensor Networks

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Cross-Layer Optimization for Wireless Sensor
Networks

• Yuecheng Zhang, Liang Cheng

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Target Applications

• Local data exchanging system
• Multi-hop Local Positioning System (MLPS)
• Global data collecting system
• Remote lab, environment sensing, and etc.
• Sensor network and robot collaborative system
• Large constructions automatic examination
• Robot Sensor network Multimedia streaming
• Sensor network and human-being collaborative
  system
• Firefighting aids, smart battlefield and etc.

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Important Issues

• Network Scale
• Cost vs. Budget
• Throughput vs. Bandwidth
• System Lifetime
• Power consumption vs. Power supply
• Existing solutions
• Low power hardware design
• Transmission power/range control
• Power-aware protocol stacks
• Power saving working modes
• Node Versatility
• Functionality vs. Resource constraints
• Functionality collecting, storing, processing,
  fusing, relaying
• Constraints computing power, storage, specific
  device and etc.

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Optimization Goals

• Enable large scale networks
• Low cost
• High efficiency
• Lengthen system lifetime
• Improve power efficiency
• Prevent system deconstruction
• Support node versatility
• Multiple functionality
• Multiple applications

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Why Cross-Layer

• Possibility
• Optimization goals can be pursued in multiple
  layers
• layered optimizations assume cross-layer
  cooperation
• Some applications do not need all layers
• Multi-hop Local Positioning System (MLPS)
• Necessity
• Optimizing single layer is not enough
• Optimizations may be conflict with each other
• One-for-all consolidate design for feasible
  applications

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Why Cross-Layer (Cont.)
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Why Cross-layer (Cont.)

• Heterogeneity
• Intra connection vs. Inter connection
• Scalability
• Correctness verification
• Reusability
• Code reuse
• Module reuse
• General purpose sensor networks

8
Current results

• Networking layer
• Self-nominating
• Floossiping
• Data-Link layer
• Efficient broadcasting MAC
• Time synchronization module
• LESSAR (LEvel Synchronization by Sender Adjuster
  and Receiver)
• Positioning module
• PLACE (Power-based Location And Coordination
  Estimation)

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Self-Nominating

• Advantages
• Robust
• Flexible
• Disadvantages
• Artificial random delay

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Future tasks

• Do some theoretical study on the system
  limitations
• System Throughput Network Scale
• Node Synchronization and Positioning accuracy
• Channel allocation and Mode decision
• Identify and justify feasible application models
• Implement the applications
• Complete the protocol stacks
• Tune the protocols and functional modules
• Optimize the applications
• Developing the research platform

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The End

• Questions?