Earth-fixed cell ID mapping for non-geostationary satellite mobility
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Solution Overview
Problem
Non-geostationary satellite communications face challenges with mobility management and location identification due to moving satellite beams, which disrupt the fixed correspondence between cell IDs and geographical areas, affecting paging, handovers, and regulatory services like emergency calls.
Innovation Solution
Implementing a method where the RAN node maps a satellite cell ID to a fixed cell ID relative to the earth, maintaining a 1:1 correspondence between cell IDs and geographical areas, allowing the RAN to handle mobility as in terrestrial networks and ensuring core network systems can use cell IDs for location information accurately.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If satellite beams move with satellite movement, then the satellite can cover different geographical areas, but the correspondence between cell IDs and geographical areas becomes unstable
Solution Approach 1:
The patent segments the cell ID into two distinct parts: a satellite-identifying portion and a beam-identifying portion. This segmentation allows the system to maintain stable satellite-level geographical correspondence while accommodating beam movement, resolving the contradiction between coverage adaptability and ID stability.
Solution Approach 2:
The patent introduces a new dimension to the cell ID structure by adding the satellite-identifying portion, transforming the traditional single-dimension cell ID into a multi-dimensional identifier system. This dimensional expansion enables simultaneous tracking of satellite position and beam location, stabilizing the cell ID-geographical area correspondence despite beam movement.
2Measurement precision
If the cell ID changes with satellite movement, then location identification is accurate for moving satellites, but mobility management becomes complex
Solution Approach 1:
By segmenting the cell ID into satellite-identifying and beam-identifying portions, the patent simplifies mobility management. The network can independently handle satellite-level and beam-level movements without complex coordinated changes, reducing overall system complexity while maintaining precise location identification.
Solution Approach 2:
The satellite-identifying portion acts as an intermediary layer between the beam-identifying portion and the core network. This intermediary structure enables the core network to manage mobility at the satellite level while the access network handles beam-level dynamics, reducing complexity in the core network.
3Device complexity
If a single cell ID is used for both satellite identification and beam identification, then the system is simple, but the system cannot support both mobility management and location identification accurately
Solution Approach 1:
The patent divides the cell ID into two functional segments: satellite-identifying portion for mobility management and location identification, and beam-identifying portion for beam-level operations. This segmentation enables the system to support both mobility management and precise location identification simultaneously while maintaining reasonable structural simplicity.
Solution Approach 2:
The segmented cell ID structure provides multi-functionality: the satellite-identifying portion supports mobility management and broad location identification, while the beam-identifying portion supports beam-specific operations. This universal structure handles multiple service requirements within a unified ID system.
Data Source
AI summary
According to some embodiments, a method performed by a network node comprises: mapping a first cell identifier associated with the network node to a second cell identifier associated with a first geographical coverage location of a beam transmitted by the non-geostationary satellite; broadcasting the first cell identifier to one or more wireless devices in the first geographical coverage location; and transmitting the second cell identifier to a core network node as part of location information for one of the one or more wireless devices in the first geographical coverage location.