Narrow-Beam Random Access Using QCL SSB Beam Broadcast
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Solution Overview
Problem
Existing wireless communications systems face inefficiencies in random access procedures due to the use of wide beams, leading to additional overhead and latency from subsequent beam refinement processes.
Innovation Solution
Implementing a method where network entities transmit both wide and narrow beams during synchronization signal block symbols, which are quasi-co-located and frequency domain multiplexed, allowing user equipment to select and utilize narrow beams for random access, thereby enhancing coverage and reducing latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If wide beams are used for random access, then coverage area is improved, but additional overhead and latency are introduced due to subsequent beam refinement processes
Solution Approach 1:
The patent transmits narrow beams during SSB occasions in advance, before the random access procedure begins. This preliminary transmission of narrow beams with QCL indications allows the UE to identify and select the appropriate narrow beam beforehand, eliminating the need for subsequent beam refinement and reducing access latency while maintaining coverage through the wide SSB beam structure
2Area of stationary object
If wide beams are used for random access, then coverage area is improved, but communication overhead increases due to subsequent beam refinement processes
Solution Approach 1:
The patent performs the beam identification and selection action in advance during the SSB occasion by transmitting narrow beams with QCL indications. This preliminary action eliminates the need for additional beam refinement signaling during the random access procedure, thereby reducing communication overhead while maintaining the coverage benefits of wide beams
3Loss of time
If narrow beams are used for random access, then latency is reduced, but coverage area decreases
Solution Approach 1:
The patent merges the advantages of both wide and narrow beams by transmitting narrow beams during SSB occasions that are quasi co-located with wide SSB beams. The UE uses the wide SSB beam for initial synchronization and coverage, while the associated narrow beams provide precise beam identification for low-latency random access, combining coverage and speed benefits in a unified approach
Data Source
AI summary
Methods, systems, and devices for wireless communications at a user equipment (UE) are described. The UE may receive control signaling indicating a plurality of synchronization signal block (SSB) occasions for a plurality of SSB beams and indicating a plurality of random access occasions. The UE may monitor a first SSB beam of the plurality of SSB beams may monitor a plurality of reference signal beams associated with the first SSB beam, where each beam of the plurality of reference signal beams has a narrower beamwidth than the first SSB beam, and where each beam of the plurality of reference signal beams is quasi co-located and frequency domain multiplexed with the first SSB beam. The UE may transmit a random access message during a first random access occasion, the first random access occasion indicating a first reference signal beam selected from the plurality of reference signal beams.