RRC Inactive Beam Reuse for Low-Power 5G Random Access
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Solution Overview
Problem
In the 5G mobile communication technology, beam management and beam failure restoration are not supported in the RRC inactive state, leading to unfavorable energy consumption for terminal devices during data transmission.
Innovation Solution
The terminal device uses previously established receive and transmit beams for downlink and uplink transmissions in the RRC inactive state, without performing beam measurement and reporting, and adjusts beams through random access when conditions warrant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If beam management and beam failure restoration are not supported in RRC inactive state, then device complexity is reduced, but energy consumption increases
Solution Approach 1:
The patent extracts beam management and beam failure restoration functions from the RRC inactive state, allowing these functions to be selectively activated only when needed. This enables the terminal device to operate in a simplified mode during inactive periods while maintaining the capability to perform beam management when data transmission requires it, thus resolving the contradiction between reduced complexity and increased energy consumption.
Solution Approach 2:
The patent performs preliminary beam establishment during the RRC connected state before transitioning to inactive state. This preliminary action ensures that beam configurations are already in place, allowing the terminal device to skip beam measurement and reporting operations during inactive state data transmission, thereby reducing energy consumption while maintaining transmission capability.
2Measurement precision
If beam measurement and reporting are performed in RRC inactive state, then beam management accuracy is improved, but power consumption increases
Solution Approach 1:
The patent applies partial action by performing beam measurement and reporting only when necessary (e.g., when data transmission is required in inactive state), rather than continuously. This selective approach maintains measurement accuracy when needed while avoiding unnecessary power consumption during periods when beam configurations remain valid, thus resolving the contradiction between measurement precision and power consumption.
3Reliability
If beam adjustment is performed frequently, then connection reliability is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic beam adjustment based on timers and triggering conditions rather than continuous adjustment. Beam failure restoration is triggered by specific events (e.g., beam failure detection, data transmission requirements) rather than occurring at fixed intervals. This event-driven periodic action maintains connection reliability while minimizing unnecessary energy consumption from frequent beam adjustments.
Data Source
AI summary
This application provides communication methods and apparatuses. One method includes: accessing, by a terminal device, an access network device by performing first random access in a radio resource control inactive (RRC inactive) state, and receiving, by the terminal device by using a first receive beam for downlink transmission of the first random access, downlink control information (DCI) transmitted by the access network device.