Hierarchical Beam Selection for Higher Random Access Capacity
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Solution Overview
Problem
Existing wireless communication systems face challenges in efficiently managing beam selection for random access, particularly in hierarchical beam architectures, leading to issues such as interference, reduced capacity, and inadequate channel quality in non-terrestrial networks like NTN.
Innovation Solution
The method involves selecting a beam for random access based on channel quality and proximity, using system information to identify the best beam among multiple beams, including narrow beams within a wide beam's coverage area, and utilizing separate bandwidth parts (BWPs) for random access transmissions to reduce interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single beam is used for random access in hierarchical beam architecture, then the device complexity is reduced, but the random access capacity and channel quality deteriorate
Solution Approach 1:
The patent segments the random access process into two distinct phases: wide beam selection for initial access based on system information, and narrow beam selection for optimized communication based on measured channel quality. This segmentation allows UEs to first connect using simple wide beam identification from system information, then transition to more sophisticated narrow beam selection for improved capacity and quality, thereby resolving the contradiction between simplicity and performance.
Solution Approach 2:
The patent implements preliminary action by having the network entity pre-configure and broadcast system information containing wide beam identifiers and associated narrow beam configurations before random access occurs. UEs perform preliminary measurements of reference signals on multiple narrow beams before selecting the optimal beam for access. This preliminary preparation enables efficient beam selection without increasing real-time complexity during the actual random access procedure.
2Productivity
If multiple narrow beams are used within a wide beam coverage area, then the random access capacity and channel quality improve, but the device complexity increases
Solution Approach 1:
The patent applies local quality by assigning different beam widths and characteristics to different spatial regions. Wide beams cover broader areas for initial access, while narrower beams provide focused, high-quality connections for specific locations within the wide beam coverage. The system information contains location-specific or region-specific beam configurations, allowing UEs to select appropriate beam qualities based on their local position and requirements, thus improving overall capacity without uniformly increasing complexity across all areas.
3Reliability
If system information is broadcast for multiple beams, then the channel quality and interference reduction improve, but the loss of information increases
Solution Approach 1:
The patent segments system information into hierarchical layers: wide beam identification information is broadcast in essential system information blocks for all UEs, while detailed narrow beam configurations and quality metrics are provided in supplementary information only for UEs that have already selected a wide beam and are considering narrow beam refinement. This segmented information distribution reduces overall overhead by avoiding redundant transmission of detailed beam information to all UEs, while still providing high-quality channel information to those who need it.
Solution Approach 2:
The patent implements partial action by broadcasting complete system information for only the most critical wide beams that cover the majority of UE locations, while providing partial or abbreviated information for less critical narrow beams. The system information includes essential parameters for wide beam selection, and optional or conditional information for narrow beam refinement based on UE capability and location. This approach provides sufficient channel quality information for reliable access without transmitting excessive information that would increase overhead.
Data Source
AI summary
Certain aspects of the present disclosure provide techniques for beam selection for random access. A method that may be performed by a user equipment (UE) includes receiving, from a network entity, via a first beam, system information associated with at least a first plurality of beams that are within a coverage area of the first beam. The method also includes selecting a second beam among at least the first plurality of beams based at least in part on the system information and performing a random access procedure via the selected second beam.