Satellite Downlink Scheduling Optimizing PDU Capacity
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Solution Overview
Problem
Existing communication systems, such as LTE-M and NB-IoT, fail to provide global scale and cost-effective connectivity for the Global Asset Tracking and Monitoring Market, particularly in terms of downlink capacity optimization.
Innovation Solution
A method and system for downlink scheduling by a satellite, where protocol data units (PDUs) are scheduled based on available capacity, spreading factors, and received power levels, allowing for efficient packing of PDUs into frequency slots and optimization of downlink capacity through frequency diversity and power control schemes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If existing communication systems (LTE-M and NB-IoT) are used, then connectivity is provided, but downlink capacity is insufficient and costs are high
Solution Approach 1:
The patent changes the parameter of spreading factor dynamically based on channel conditions and traffic requirements. By adjusting the spreading factor parameter, the system can adapt downlink capacity to match actual needs, improving both capacity utilization and connectivity efficiency in satellite communication
2Quantity of substance
If more PDUs are scheduled in a slot, then downlink capacity increases, but available slot capacity is exceeded causing scheduling failures
Solution Approach 1:
The patent implements dynamic slot capacity thresholds that adjust based on channel conditions, traffic patterns, and satellite resources. This dynamic approach allows the system to maximize PDU scheduling while maintaining reliability by adapting to changing conditions rather than using fixed thresholds
Solution Approach 2:
The system uses feedback from uplink received power measurements and downlink channel conditions to adjust scheduling decisions. By continuously monitoring channel quality and adjusting PDU scheduling accordingly, the system maintains high scheduling reliability while maximizing downlink capacity utilization
3Quantity of substance
If spreading factor is reduced to increase capacity, then more PDUs fit in a slot, but signal quality deteriorates
Solution Approach 1:
The patent applies different spreading factors to different PDUs or different time slots based on local channel conditions and traffic requirements. This localized optimization allows the system to use lower spreading factors (higher capacity) in good channel conditions while maintaining higher spreading factors (better signal quality) when needed, achieving both high packing density and signal quality
4Device complexity
If satellite schedules PDUs based on fixed capacity thresholds, then scheduling is simple, but downlink capacity is not optimized
Solution Approach 1:
The patent transitions from fixed capacity thresholds to dynamic thresholds that adapt to channel conditions, satellite resources, and traffic patterns. This dynamic scheduling approach optimizes downlink capacity utilization by adjusting scheduling parameters in real-time while maintaining manageable algorithm complexity through structured decision-making frameworks
Data Source
AI summary
An illustrated embodiment disclosed herein is a method for downlink scheduling. The method includes scheduling, by a satellite, one or more protocol data units (PDUs) in a slot, determining, by the satellite, whether available capacity of the slot is less than a predetermined threshold, responsive to determining that the available capacity of the slot is not less than the predetermined threshold, scheduling, by the satellite, a second one or more PDUs in the slot, and responsive to determining that the available capacity of the slot is less than that the predetermined threshold, transmitting, by the satellite, the slot to an endpoint. In some embodiments, the one or more PDUs are associated with a first spreading factor (SF). In some embodiments, the first SF is lower than a second SF. In some embodiments, the second one or more PDUs are associated with the second SF.