Default PUCCH and SRS Beam Determination in 5G
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Solution Overview
Problem
Current wireless communication systems, particularly in LTE and 5G-NR, face challenges in determining a default beam for dedicated PUCCH and SRS transmissions when spatial relationship information or pathloss reference signals are not configured, leading to undefined scenarios and potential communication inefficiencies.
Innovation Solution
A wireless device determines a default beam based on configured pathloss reference signals, control resource sets, and transmission configuration indications, using radio resource control signaling to select from alternative component carriers, recent transmission beams, or other communication channels when primary configurations are absent.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If spatial relationship information or pathloss reference signals are not configured, then the system maintains configuration flexibility and reduces signaling overhead, but the default beam determination becomes undefined leading to communication inefficiencies
Solution Approach 1:
The patent applies preliminary action by pre-defining default beam determination rules that are executed when spatial relationship information or pathloss reference signals are not configured. The system establishes fallback mechanisms in advance (using QCL assumptions from CORESETs, or defaulting to beam index 0) so that beam determination is always defined, eliminating the undefined scenario while maintaining configuration flexibility.
2Measurement precision
If the system uses configured pathloss reference signals and control resource sets for beam determination, then beam determination accuracy is improved, but the system requires more configuration elements increasing device complexity
Solution Approach 1:
The patent applies self-service by enabling the system to determine default beams autonomously using available configurations. When pathloss reference signals are configured, the system self-determines the default beam based on QCL assumptions from associated CORESETs without requiring additional explicit beam indication signaling, thus improving accuracy while avoiding increased configuration complexity.
3Stability of the object's composition
If the system establishes fallback mechanisms for default beam determination, then communication stability is improved, but the determination process becomes more complex
Solution Approach 1:
The patent applies segmentation by dividing the beam determination process into distinct segments or stages: first attempting to use QCL assumptions from configured CORESETs, and if those are unavailable, falling back to default beam index 0. This segmented approach provides clear fallback mechanisms that improve communication stability while keeping each segment's logic simple and manageable.
Data Source
AI summary
Apparatuses, systems, and methods for a user equipment device (UE) to determine a default beam for a dedicated PUCCH/SRS in a CC. The UE may determine a pathloss RS has been configured in the CC, e.g., responsive to the UE determining that spatial relationship information for a default transmission beam has not been configured and determine the default beam for transmissions based, at least in part, on the (configured) pathloss RS. Additionally, responsive to determining that the pathloss RS has not been configured in the CC, the UE may determine that no CORESETs/TCI states for a PDSCH in the CC have been configured and determine the default beam for transmissions based, at least in part, on a default transmission beam in another CC, a CC index, a PRACH procedure; a PUSCH transmission; an SRS transmission, and/or a PUCCH transmission.