User Equipment Random Access Response Reception in NR Beamforming
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Solution Overview
Problem
User equipment may fail to receive a random access response appropriately when beam forming is applied in the New Radio (NR) wireless communication system, particularly due to issues with beam alignment and quasi-co-location relationships between antenna ports.
Innovation Solution
The technique involves configuring a dedicated CORESET or fallback CORESET for the user equipment to receive control signals with a beam that has a quasi-co-location relation with the synchronization signal block, allowing the user equipment to correctly receive random access responses by switching to a specific beam or CORESET during the random access procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If beam forming is applied in NR system, then transmission loss in higher frequency band is compensated, but user equipment may fail to receive random access response appropriately
Solution Approach 1:
The patent segments the CORESET configuration into different types (first CORESET and second CORESET) with distinct beam association rules. The first CORESET is associated with a first beam for initial random access, while the second CORESET is associated with a second beam for subsequent communications, allowing the system to maintain beam forming benefits while ensuring reliable random access response reception through appropriate beam selection for each phase
Solution Approach 2:
The patent introduces a quasi-co-location relationship as an intermediary mechanism to establish the connection between SSB and DMRS antenna ports. This quasi-co-location relationship serves as a mediator that enables the user equipment to determine the appropriate beam for receiving random access response by inferring beam information from the SSB-DMRS association, thus resolving the beam alignment issue without compromising the beam forming gain
2Power
If beam forming with higher beam gain is applied, then transmission loss in higher frequency band is compensated, but beam alignment issues arise for random access procedure
Solution Approach 1:
The patent applies preliminary action by pre-establishing the quasi-co-location relationship between SSB and DMRS antenna ports before the random access procedure begins. This pre-configured relationship enables the user equipment to automatically determine the correct beam for receiving random access response without requiring manual beam alignment or complex real-time beam selection, thus simplifying the beam alignment operation while maintaining high beam gain
Solution Approach 2:
The patent uses the SSB beam direction information as a copy or reference for determining the DMRS beam direction. By copying the beam association relationship from the SSB (which the user equipment can reliably detect) to the DMRS (which schedules the random access response), the system avoids direct beam alignment complexity while ensuring the correct beam is used for response reception
Data Source
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AI summary
A user equipment includes a reception unit that receives, from a base station, control information as a trigger to start a random access procedure; a transmission unit that selects a resource for transmitting a random access signal, and transmits, to the base station, the random access signal using the resource, wherein the reception unit monitors a response to the random access signal using a resource dedicated to the random access procedure based on the trigger.