Adaptive Transmission Energy Consumption in LoRaWAN End Nodes
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Solution Overview
Problem
Low-power, wireless embedded devices in the IoT face challenges in adapting transmission settings due to varying channel conditions, particularly in LoRaWAN networks where the spreading factor is set slowly, once per day, limiting data rate and range.
Innovation Solution
An end node adaptively sets the energy level of forthcoming messages by determining the path loss from a beacon signal, adjusting power, forward error correction coding rate, spreading factor, and modulation format based on received power and performance goals, while a central node periodically transmits a beacon signal and configuration signal to facilitate these adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the spreading factor is set slowly (once per day) as in conventional LoRaWAN networks, then device power consumption is reduced, but data rate and communication range are limited
Solution Approach 1:
The patent implements dynamic adjustment of transmission parameters including spreading factor, power level, and data rate based on real-time channel conditions. The system transitions from static once-per-day configuration to continuous adaptive adjustment, allowing the LoRaWAN network to optimize performance metrics such as data rate and range while managing power consumption dynamically rather than statically
Solution Approach 2:
The system changes physical transmission parameters (spreading factor, power, data rate) in response to measured channel conditions. By continuously monitoring and adjusting these parameters, the system resolves the contradiction between power consumption and data rate/productivity, achieving both energy efficiency and high performance when channel conditions warrant it
2Area of stationary object
If transmission power is increased to extend communication range, then coverage area is improved, but energy consumption increases
Solution Approach 1:
The system dynamically adjusts transmission power based on real-time channel conditions and distance estimates. Rather than using fixed high power to ensure coverage, the system adapts power levels to actual needs, extending coverage area only when channel conditions and distance requirements warrant the additional energy expenditure
Solution Approach 2:
The system changes transmission power as a variable parameter in response to measured path loss and channel quality. This allows the network to achieve extended coverage area while minimizing energy consumption by using higher power only when necessary, resolving the contradiction between coverage and power usage
3Reliability
If transmission parameters are adjusted frequently to adapt to channel conditions, then data reliability is improved, but device complexity increases
Solution Approach 1:
The system implements feedback mechanisms where transmission parameters are adjusted based on measured channel conditions and reception quality. This feedback-driven adaptation improves data reliability by continuously optimizing for current conditions while managing device complexity through structured feedback loops rather than uncontrolled parameter changes
Solution Approach 2:
The system performs self-adjustment of transmission parameters based on its own measurements of channel conditions and reception quality. This self-service capability improves reliability through adaptive optimization while managing complexity by eliminating the need for external control systems, allowing the device to autonomously optimize its own transmission parameters
Data Source
AI summary
A method, of operating an end node to wirelessly communicate with a central node, includes: receiving wirelessly a current instance of a beacon signal periodically-transmitted from the central node; measuring a received power, PB-RX, of the beacon signal; reading locally-stored values of PB-TX and G representing a presumed transmitted power of the beacon signal and a performance goal of the end node, respectively; determining, for a given channel, a path loss, PL, based on the PB-RX and the PB-TX; and adaptively setting an energy level, EN-TX, of a forthcoming message to be transmitted from the end node by adaptively determining, based on PL and G, at least two of: a level of power, PN-TX; a forward error correction coding rate, c; and a spreading factor, SF; and a modulation format, M.