NAS Coverage Signaling for Dynamic Satellite Access Prediction
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Solution Overview
Problem
Existing methods for transmitting satellite coverage information to user equipment in 4G and 5G networks are inefficient, requiring complex calculations and resource-intensive processes, and are not optimized for battery life or compatibility with all user devices.
Innovation Solution
A method using Non-Access Stratum (NAS) signaling protocols to transmit dynamic coverage availability information from a core network to user equipment, allowing centralized prediction and management of satellite coverage without relying on user equipment calculations or dedicated data connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If satellite ephemerides are broadcast via radio broadcast channel, then user equipment can calculate satellite positions, but the method requires complex calculations and excessive energy consumption
Solution Approach 1:
The patent introduces an intermediary system (network infrastructure including gNB and AMF) that calculates satellite coverage information centrally and transmits it to user equipment via NAS signaling. This mediator performs the complex calculations on the network side rather than requiring each user equipment to perform them locally, thereby reducing energy consumption while maintaining information accuracy.
Solution Approach 2:
The patent replaces the mechanical calculation approach (where user equipment performs orbital calculations based on ephemerides) with a signaling-based approach. Coverage information is transmitted directly through NAS signaling messages, substituting the need for complex local computations with a simpler information reception and processing mechanism.
2Loss of information
If user equipment performs orbit propagation calculations, then coverage can be determined, but device complexity and resource requirements increase
Solution Approach 1:
The network infrastructure acts as an intermediary that performs the complex orbital propagation calculations and coverage determination centrally. The AMF receives satellite ephemerides, performs calculations to determine coverage areas, and transmits the results to user equipment, thereby eliminating the need for complex computational capabilities in user devices.
Solution Approach 2:
Instead of having user equipment calculate coverage based on received ephemerides, the patent inverts the approach by having the network calculate and determine coverage information first, then transmit it to user equipment. This reversal places the computational burden on the network side where resources are more abundant.
3Loss of information
If HTTP requests are used for coverage information, then data can be retrieved, but dedicated data connections are required and not all devices are compatible
Solution Approach 1:
The patent utilizes NAS signaling, which is a universal protocol already implemented in all 3GPP-compliant user equipment for mobility management and session management. By repurposing this existing universal signaling mechanism for coverage information transmission, the solution ensures broad device compatibility without requiring dedicated data connections or HTTP protocol support.
Solution Approach 2:
The NAS signaling layer serves multiple functions including mobility management, session management, and now coverage information transmission. This multi-functionality allows the same signaling infrastructure to serve diverse purposes, ensuring that all user equipment capable of basic NAS signaling can access coverage information without additional compatibility requirements.
4Reliability
If ephemerides of multiple satellites are broadcast, then coverage prediction can be improved, but signaling overhead and processing load increase
Solution Approach 1:
The patent extracts only the essential coverage information from the complete satellite ephemerides data. Instead of transmitting full ephemeris records for multiple satellites, the system calculates coverage areas and extracts the relevant coverage status information, transmitting only what is necessary for the user equipment to determine service availability, thereby reducing signaling overhead.
Solution Approach 2:
The system performs calculations for multiple satellites to ensure accurate coverage prediction, but transmits only the resulting coverage information rather than all intermediate calculation data. This partial action approach maintains prediction accuracy by considering multiple satellites while reducing the quantity of transmitted information to only the essential coverage status.
Data Source
AI summary
The present invention relates to a method for transmitting dynamic coverage availability information between a core network, comprising an access and mobility management function and collaborative with an access network having dynamic coverage, and a user equipment able to connect to the access network, the method comprising the following steps, for the access and mobility management function:receiving a set of points characterizing anticipated positions of the user equipment,retrieving dynamic coverage availability information for at least one point belonging to the anticipated positions of the user equipment,sending to the user equipment a signaling message, in the Non-Access Stratum NAS layer, comprising the retrieved dynamic coverage availability information.