NTN SSB Power Compensation for Low-Overhead Cell Selection
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Solution Overview
Problem
In non-terrestrial networks, terminals face increased power consumption and difficulty in receiving synchronization signals due to suspended beams, leading to communication failures and inefficient power management, especially when using multiple beams with varying sizes and transmission powers.
Innovation Solution
A method for terminals to measure and compare reception powers of different beam types (narrow and wide) to select the optimal cell based on power differences, reducing the need for frequent power adjustments and overhead signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the satellite uses narrow beams allocated to different spatial areas, then the coverage of all areas within a cell can be achieved, but the terminal power consumption increases due to monitoring all SSBs
Solution Approach 1:
The patent segments SSB monitoring into two parts: wide beam SSBs for initial cell search and narrow beam SSBs for refined beam selection. The terminal first monitors wide beam SSBs to identify candidate cells, then selectively monitors only relevant narrow beam SSBs based on the wide beam results, reducing overall monitoring burden and power consumption while maintaining complete coverage capability.
Solution Approach 2:
The patent applies preliminary action by having the terminal perform wide beam SSB monitoring first to identify candidate cells before proceeding to narrow beam SSB monitoring. This preliminary step allows the terminal to filter out irrelevant narrow beams in advance, reducing the total number of SSBs that need to be monitored and thus lowering power consumption while ensuring no coverage area is missed.
2Use of energy by moving object
If the satellite transmits signals using both wide beams and narrow beams, then the terminal power consumption is reduced, but the cell coverage cannot be maintained
Solution Approach 1:
The patent segments the beam transmission into two functional layers: wide beams for coverage indication and narrow beams for service delivery. By this segmentation, the terminal can rely on wide beam SSBs for cell identification and coverage assessment, then use narrow beam SSBs only when needed for specific beam selection, thereby maintaining coverage while reducing power consumption.
Solution Approach 2:
The patent uses wide beam SSB transmission as a preliminary action that provides terminal with coverage information before narrow beam transmission. This preliminary wide beam indication allows terminals to determine whether they are within coverage area without monitoring all narrow beam SSBs, thus maintaining cell coverage integrity while reducing terminal power consumption.
3Device complexity
If beams are temporarily suspended to limit the number of simultaneously used beams, then the system complexity is reduced, but the terminal may fail to receive SSB at configured reception time
Solution Approach 1:
The patent applies periodic action by implementing beam suspension and activation in periodic cycles. Beams are temporarily suspended for certain periods to reduce complexity, then activated again in subsequent periods. The SSB transmission periodicity is configured to align with these beam activation patterns, ensuring that terminals can reliably receive SSBs at expected intervals while the system maintains manageable complexity through controlled beam suspension.
Solution Approach 2:
The patent implements feedback mechanisms where the network monitors terminal SSB reception status and adjusts beam suspension/activation patterns accordingly. When terminals fail to receive SSBs due to beam suspension, the system receives feedback and modifies the beam scheduling to ensure reliable SSB delivery, thus maintaining reliability while managing system complexity through adaptive beam control.
4Reliability
If the terminal repeatedly attempts to receive synchronization signals periodically over a long period, then the SSB reception reliability is improved, but the battery consumption increases
Solution Approach 1:
The patent applies preliminary action by having the terminal perform wide beam SSB monitoring first to quickly identify candidate cells and determine whether SSB reception is likely to succeed. This preliminary assessment allows the terminal to avoid prolonged repeated monitoring attempts in cells where SSB reception is unlikely, thus improving reception reliability through targeted monitoring while reducing unnecessary battery consumption from futile repeated attempts.
Solution Approach 2:
The patent implements partial monitoring action where the terminal monitors only a subset of SSBs (wide beams and selected narrow beams) rather than all SSBs in the cell. This partial monitoring approach maintains sufficient SSB reception reliability for cell selection and handover while significantly reducing the battery consumption associated with monitoring every SSB periodically over long periods.
Data Source
AI summary
A method of a terminal may comprise: acquiring, from a first base station, first information indicating a difference between a reception power of a first reference beam of the first base station and a reception power of a first SSB beam of the first base station; receiving, from the first base station, second information indicating a difference between a reception power of a second reference beam of a second base station and a reception power of a second SSB beam of the second base station; measuring a first signal of the first base station; measuring a second signal of the second base station; and selecting a cell operated by the first base station or the second base station based on at least one of a first measurement result of the first signal, a second measurement result of the second signal, the first information, or the second information.