Aperiodic SI Broadcast Scheduling for NTN Satellite Coverage
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Solution Overview
Problem
The rigid periodic broadcast of system information in non-terrestrial networks (NTN) leads to unnecessary signaling overhead, resource consumption, and increased channel occupancy due to varying needs for SI availability, particularly during satellite switches and feeder link changes.
Innovation Solution
Implement aperiodic broadcast of system information using irregular or periodically recurring broadcast time patterns, such as overlay-windows, to adapt to the varying needs for SI availability, allowing more frequent broadcasts during critical periods and reducing unnecessary transmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If periodic broadcast of system information is implemented in NTN, then SI availability is ensured, but signaling overhead and resource consumption increase unnecessarily
Solution Approach 1:
The patent applies periodic action by implementing aperiodic SI broadcast with irregular or periodically recurring broadcast time patterns. Instead of continuous periodic broadcasting, the system uses overlay-windows that may recur periodically but contain irregular broadcast patterns within them, allowing the network to adapt broadcast frequency to actual UE needs while maintaining periodic structure for predictability.
Solution Approach 2:
The patent implements dynamics by making the SI broadcast schedule adaptive rather than rigid. The network can dynamically adjust broadcast frequency within overlay-windows based on UE requests and network conditions, transitioning between more frequent broadcasts during critical periods (satellite switches, feeder link changes) and less frequent broadcasts during stable periods.
2Loss of time
If frequent SI broadcast is implemented, then SI acquisition timeliness is improved, but channel occupancy and resource consumption increase
Solution Approach 1:
The patent applies local quality by implementing different broadcast frequencies in different time periods and for different UEs. Within overlay-windows, the system can provide more frequent broadcasts when specific UEs need SI (local need) while maintaining less frequent broadcasts in other periods, rather than uniformly increasing broadcast frequency for all UEs at all times.
Solution Approach 2:
The patent implements partial action by broadcasting SI only when necessary within overlay-windows rather than continuously. The system provides excessive broadcast frequency only during critical periods when UEs actually need SI (such as during satellite switches), and reduces or eliminates broadcasts during stable periods, avoiding unnecessary channel occupancy.
3Loss of energy
If aperiodic broadcast with irregular patterns is implemented, then resource efficiency is improved, but system complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the broadcast schedule into regular periodic windows (overlay-windows) and irregular broadcast periods within them. This segmentation allows the system to maintain simple periodic structure at the overlay-window level while implementing complex irregular patterns within individual windows, reducing overall scheduling complexity.
Solution Approach 2:
The patent implements nesting by placing irregular broadcast patterns within the structured overlay-windows. The irregular aperiodic broadcasts are nested within the periodic overlay-window framework, allowing the system to combine simple periodic scheduling at the outer level with complex adaptive patterns at the inner level, managing complexity through hierarchical organization.
Data Source
AI summary
A method performed by a wireless device (110b, 110c) comprises receiving (612) system information (SI) broadcast from a network node, the SI broadcast received according to an aperiodic configuration. In particular embodiments, the aperiodic configuration comprises an initial period followed by a subsequent period, wherein a frequency of the SI broadcast during the initial period is greater than a frequency of the SI broadcast during the subsequent period. The initial period may occur when a satellite takes over coverage of a geographical area in which the wireless device is located, and the subsequent period may occur while the satellite maintains coverage of the geographical area in which the wireless device is located.