Satellite Tracking Area Update Method Reducing Overhead
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Solution Overview
Problem
In satellite communications, frequent unnecessary tracking area updates (TAU) occur due to the fixed binding of tracking areas to geographical locations, leading to inefficient use of radio resources and increased overheads, as user equipment (UE) may receive tracking area codes (TACs) from overlapping areas, causing unnecessary updates.
Innovation Solution
The method involves user equipment receiving TACs with geographical location information, determining if an update is needed based on the TAC and tracking area list (TAL), and performing updates only when a change in tracking area is confirmed, using span indication information to support non-uniform tracking area designs and adapt to unbalanced network service loads and latitude distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If tracking areas are fixedly bound to geographical locations, then location management is simplified, but unnecessary tracking area updates occur frequently due to TA overlaps
Solution Approach 1:
The patent makes the tracking area binding dynamic by associating TAs with satellite cell identities rather than fixed geographical locations. When satellites move or beams are adjusted, the TA bindings automatically update, allowing the system to adapt to changing coverage areas while preventing unnecessary TAU events caused by static TA boundaries overlapping with moving satellite beams.
Solution Approach 2:
The patent changes the binding parameter from geographical coordinates to satellite cell identifiers. This parameter transformation allows the network to track UE location based on which satellite cells are currently serving them, rather than comparing fixed geographical TA boundaries, thereby eliminating unnecessary TAU triggered by TA overlap in satellite scenarios.
2Reliability
If tracking area codes are broadcast widely to cover overlapping areas, then coverage is ensured, but user equipment receives multiple TACs causing unnecessary updates
Solution Approach 1:
The patent implements feedback mechanisms where the network monitors which satellite cells are actually serving UEs and uses this information to determine TA bindings. This feedback loop ensures that TACs are broadcast only in areas where they are currently valid, preventing UEs from receiving and processing unnecessary TACs from overlapping but non-serving areas, thus reducing energy consumption and unnecessary TAU events.
3Measurement precision
If frequent tracking area updates are performed to ensure accurate location tracking, then location accuracy is improved, but network overhead and resource consumption increase
Solution Approach 1:
The patent performs preliminary binding of tracking areas to satellite cell identities before UEs enter coverage areas. This pre-configuration allows UEs to determine in advance which TACs are valid for their current satellite cell, eliminating the need for frequent TAU events to maintain location accuracy. The preliminary binding ensures that location tracking remains accurate while minimizing network overhead by preventing unnecessary update messages.
Data Source
AI summary
User equipment receives at least one TAC that is broadcast by a network device, where the TAC includes geographical location information, and the geographical location information is used to indicate a geographical location of a preset location point in a TA corresponding to the TAC. The user equipment determines, based on the TAC and a tracking area list (TAL), whether the TAL needs to be updated. If it is determined that the TAL needs to be updated, the user equipment sends a tracking area update request to the network device. The user equipment receives a response message, of the tracking area update request, returned by the network device.