NTN Beam Sweeping Using Dual Broadcast Signals for Faster Access
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Solution Overview
Problem
The current NR beam sweeping solution in NTN systems is inefficient, leading to prolonged satellite capture times, especially for UEs at edge beam positions, where the satellite may move out of range during the alignment process, necessitating repeated frequency and beam sweeping, which becomes increasingly difficult as the number of beams increases.
Innovation Solution
Implementing a method where UEs receive a first broadcast signal with a reduced periodicity and wider beam width, allowing for quicker determination of the strongest receive beam direction, and using a mapping relationship to efficiently access the satellite by receiving a second broadcast signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE uses the current NR beam sweeping solution with default 20ms periodicity, then the system maintains standard compatibility, but the satellite capture time becomes excessively long (52.28s for single frequency)
Solution Approach 1:
The patent introduces a first broadcast signal with reduced periodicity (shorter than 20ms) that is sent before the second broadcast signal. The UE performs beam sweeping and captures this first signal preliminarily to determine the optimal receive beam direction and frequency, which then guides the subsequent reception of the second broadcast signal. This preliminary action significantly reduces the overall satellite capture time while maintaining compatibility with standard NR protocols.
2Area of stationary object
If the UE performs beam sweeping across all directions to align with the satellite, then complete coverage is achieved, but the time required increases proportionally with the number of beams
Solution Approach 1:
The patent segments the beam sweeping process into two distinct phases: first, a coarse beam sweeping phase using the first broadcast signal with wider beam width and reduced periodicity to quickly identify the approximate direction and optimal receive beam; second, a fine tuning phase using the second broadcast signal to complete the alignment. This segmentation allows the UE to cover all beam directions systematically while reducing the time spent in each phase, particularly in the initial coarse search.
3Adaptability or versatility
If the UE is at an edge beam position, then the satellite may move out of range during alignment, but repeated frequency and beam sweeping becomes increasingly difficult as the number of beams increases
Solution Approach 1:
For UEs at edge beam positions, the patent applies preliminary action by having the UE quickly capture the first broadcast signal with reduced periodicity to determine the optimal receive beam direction and frequency before the satellite moves out of range. This preliminary beam and frequency determination, guided by the first broadcast signal, allows the UE to be pre-positioned correctly, eliminating the need for repeated complex frequency and beam sweeping operations that would otherwise be necessary as the number of beams increases.
Data Source
AI summary
Embodiments of this disclosure provide a non-terrestrial network (NTN) access method and a communication apparatus. The method includes: A communication apparatus receives at least one first broadcast signal based on a first periodicity or continuously receives the at least one first broadcast signal, to obtain a target first broadcast signal, where the first periodicity is less than a minimum sending periodicity of a second broadcast signal; receives at least one second broadcast signal based on the target first broadcast signal, to obtain a target second broadcast signal; and performs access based on the target second broadcast signal. When a sending periodicity of the first broadcast signal is reduced, efficiency of traversing all receive beam directions is higher, so that a strongest receive beam direction can be determined more quickly, to improve satellite access efficiency.