Timing Advance Validation for RRC Inactive Small Data Transmission
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Solution Overview
Problem
Inefficient communication of small data amounts in RRC connected state with high signaling overhead in 5G networks, necessitating improved mechanisms for timing advance validation and beam filtering during small data transmission (SDT) in RRC inactive state.
Innovation Solution
A wireless device performs timing advance validation by measuring and filtering reference signal received power (RSRP) values using beam sweeping and L1 filtering, with TA values provided through RRC release, MAC CE, and RAR messages, to align UL transmissions efficiently in RRC inactive state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a wireless device transmits small amounts of data while in RRC connected state, then data transmission can be performed, but signaling overhead increases and communication efficiency decreases
Solution Approach 1:
The patent extracts the data transmission function from the RRC connected state and enables it to operate independently in the RRC inactive state through configured grant resources. This allows small data packets to be transmitted without requiring full RRC connection establishment, thereby reducing signaling overhead while maintaining productivity.
Solution Approach 2:
The network configures grant resources and timing advance values in advance during the RRC connected state or idle state. These pre-configured resources are stored and directly usable when small data needs to be transmitted in the inactive state, eliminating the need for real-time resource allocation signaling and improving transmission efficiency.
2Measurement precision
If timing advance validation is performed by measuring reference signals without filtering, then TA validation can be completed, but measurement precision decreases due to signal variations
Solution Approach 1:
The patent applies L1 filtering to reference signal measurements in advance before using them for TA validation. By pre-filtering the reference signals to obtain stable RSRP values, the system ensures accurate TA validation while avoiding the complexity of real-time filtering during the validation process itself.
Solution Approach 2:
The system continuously monitors reference signal measurements and uses L1 filtering to provide feedback-adjusted RSRP values for TA validation. This feedback mechanism maintains measurement precision by compensating for signal variations while managing complexity through standardized filtering algorithms.
3Speed
If a wireless device transitions from RRC inactive state to RRC connected state for data transmission, then full communication capabilities are available, but latency increases due to state transition overhead
Solution Approach 1:
The network pre-configures grant resources, timing advance values, and other transmission parameters while the device is in RRC idle or inactive state. When small data needs to be transmitted, the device can immediately use these pre-configured resources without transitioning to connected state, eliminating state transition latency while maintaining full transmission capability for small packets.
Solution Approach 2:
The wireless device autonomously uses pre-configured grant resources and timing advance values to transmit small data packets in the inactive state without network intervention. This self-service capability eliminates the need for random access procedures and state transitions, reducing latency while maintaining transmission speed.
Data Source
AI summary
This application regards timing advance (TA) validation for small data transmission (SDT) by a wireless device. The wireless device calculates a RSRP value based on a receipt of one or more messages, where the particular messages to trigger the RSRP calculation can be indicated to the wireless device by a flag in a message received from a cellular wireless network. Exemplary messages include a radio resource control (RRC) release message, with or without a SDT configuration, a medium access control (MAC) control element (CE) TA command message, or a random-access response (RAR) message. The wireless device measures and stores the RSRP value to use for subsequent validation of a TA value.