Temperature-Compensated Radio Node Timing for Collision-Free Mesh Links
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Solution Overview
Problem
Wireless mesh networks face inefficiencies due to packet collisions and power consumption issues, especially in applications requiring low power and small size, where nodes are closely spaced and interference is substantial.
Innovation Solution
A packet switched transport method using frequency hopping time-division multiple access, where intelligent nodes minimize duty cycling through synchronization, with each link assigned a specific time-channel offset in a superframe, ensuring efficient spectrum use and minimal power expenditure, potentially achieving 100% data utilization with reduced guard bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If nodes are closely spaced to reduce size and power consumption, then device size and power consumption decrease, but interference and packet collisions increase
Solution Approach 1:
The communication medium is segmented into multiple frequency channels, and each link is assigned a specific time-channel offset. This segmentation allows multiple nodes to communicate simultaneously on different frequencies without interference, resolving the packet collision problem that arises when nodes are closely spaced.
Solution Approach 2:
The system uses periodic time-division multiple access where each link is assigned specific time slots within a superframe structure. Nodes transmit periodically at their assigned time offsets, which eliminates random access collisions and ensures reliable communication in dense networks.
2Use of energy by moving object
If duty cycling is increased to save power, then power consumption decreases, but network synchronization and data transmission efficiency worsen
Solution Approach 1:
The system performs preliminary synchronization at the beginning of each superframe, establishing time references and frequency offsets before data transmission begins. This preliminary action allows nodes to enter low-power sleep modes between superframes while maintaining synchronization, thus reducing power consumption without sacrificing transmission efficiency.
Solution Approach 2:
The superframe structure provides continuous useful action by maintaining persistent frequency and time synchronization across all nodes. Even when nodes are in sleep mode, the synchronized structure ensures that wake periods are efficiently utilized for data transmission without requiring extensive re-synchronization, thereby maintaining high productivity.
3Reliability
If frequency hopping is used to reduce interference, then reliability improves, but device complexity and power consumption increase
Solution Approach 1:
The system implements dynamic frequency assignment where each link is assigned a specific frequency offset within the superframe structure. This dynamic assignment allows the radio to operate on different frequencies for different links, providing interference resistance similar to frequency hopping, but with simplified control through predetermined offset assignments rather than complex hopping sequences.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances network reliability and power efficiency by minimizing redundant links and collisions, increasing bandwidth utilization while maintaining low power consumption, especially in dense sensor network environments.
Implementation Method 1
a 32 kHz crystal oscillator
Implementation Method 2
a temperature sensor that provides input to a microcontroller
Implementation Method 3
The microcontroller also provides temperature compensation for the oscillator frequency
Data Source
AI summary
A device for a node in a digraph network comprising is disclosed. The device comprises an internal time reference, a radio receiver, a radio transmitter. The device further comprises a temperature sensor for stabilizing the internal time reference against drifting with respect to an internal time reference of another node in the network and a microprocessor for managing the reception and transmission of information.