Distributed Sleep Management for Wireless Sensor Networks
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Solution Overview
Problem
Existing energy management methods for wireless networks, particularly in heterogeneous networks with both battery-powered and mains-powered nodes, fail to efficiently manage sleep schedules, leading to increased energy waste due to synchronization issues and collisions in multi-hop networks.
Innovation Solution
Implementing a distributed sleep management system where battery-powered nodes independently determine their active and sleep periods based on internal network activities, partitioning their active period into receiving and transmission phases to reduce collisions and energy waste, while mains-powered nodes remain active.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If centralized sleep control mechanism is used to synchronize nodes, then packet collision is reduced, but idle time increases resulting in additional energy waste
Solution Approach 1:
The patent segments the network control into two parts: centralized sleep schedule determination (sink node) and distributed execution (data nodes). This allows the network to benefit from centralized coordination for collision reduction while avoiding the energy waste of centralized synchronization control, as each node independently executes its schedule without requiring synchronization packets.
Solution Approach 2:
Data nodes independently determine and execute their own sleep schedules based on information from the sink node, without requiring continuous synchronization control. This self-service approach eliminates the energy waste associated with synchronization packet transmission and reception while maintaining effective sleep management.
2Reliability
If synchronization operations are implemented across the network, then packet collision is reduced, but synchronization packet transmission and receiving result in extra energy waste
Solution Approach 1:
The sink node provides sleep schedule information to data nodes in advance, allowing nodes to pre-determine their active and sleep periods without requiring ongoing synchronization. This preliminary action eliminates the need for continuous synchronization packet exchange, reducing energy consumption while maintaining collision reduction benefits.
Solution Approach 2:
The patent extracts the synchronization function from the sleep control mechanism. Instead of using synchronization packets to coordinate sleep schedules, the system uses independent schedule determination based on pre-provided information, removing the energy-consuming synchronization packet transmission while preserving the benefits of coordinated sleep management.
3Loss of energy
If all nodes sleep during pre-specified time periods, then energy consumption is reduced, but network responsiveness and data transmission capability deteriorate
Solution Approach 1:
The patent implements dynamic sleep schedules where data nodes independently adjust their active and sleep periods based on their specific data transmission needs and network conditions. This dynamic approach allows nodes to remain active when data transmission is required while sleeping during low-activity periods, maintaining productivity while reducing energy consumption.
Solution Approach 2:
Each data node determines its own sleep schedule based on local conditions and data requirements, rather than following a uniform network-wide schedule. This local quality approach ensures that nodes with high data transmission needs remain active longer, while nodes with lower needs can sleep more, optimizing both energy consumption and data transmission capability across the network.
Data Source
AI summary
A network of nodes includes data nodes and at least one sink node to exchange packets between the sink node and the data nodes in a multi-hop manner. The data nodes include a battery powered node (BPN) having a transceiver, a memory, and a battery to provide energy to components of the BPN. The BPN includes a processor to determine a sleep schedule of the BPN independently from the sleep schedules of other data nodes and independently from commands transmitted by the sink node. The processor of the BPN switches the transceiver ON and OFF according to the sleep schedule to form an active period and a sleep period of the BPN. Also, the processor partitions at least part of the active period into a receiving (RX) period and a transmission (TX) period and causes the transceiver to transmit the data packets only during the TX period.