Small Data Transmission Timer Management in RRC Inactive State
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Solution Overview
Problem
Current wireless communication systems, such as the 5G NR system, face challenges in efficiently managing small data transmission in the RRC_INACTIVE state, leading to unnecessary power consumption and signaling overhead due to frequent connection setups and releases.
Innovation Solution
A method for small data transmission (SDT) in wireless communication systems, where a user equipment (UE) receives system information with an SDT configuration including an SDT-specific timer, initiates an SDT procedure in the RRC_INACTIVE state, triggers a Buffer Status Report (BSR), and restarts the SDT-specific timer upon BSR triggering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE transitions to RRC_CONNECTED state for small data transmission, then data transmission reliability is improved, but power consumption and signaling overhead increase
Solution Approach 1:
The patent segments the connection management by introducing a dedicated SDT configuration that allows small data transmission in RRC_INACTIVE state without full connection setup. This separates the small data transmission path from the general data transmission path, enabling selective connection state management based on data size and type.
Solution Approach 2:
The patent implements dynamic state transitions by allowing the UE to remain in RRC_INACTIVE state during small data transmission through SDT, rather than forcing a transition to RRC_CONNECTED. The SDT configuration enables flexible, dynamic decision-making about connection state based on real-time transmission needs.
2Reliability
If the UE transitions to RRC_CONNECTED state for small data transmission, then data transmission reliability is improved, but signaling overhead increases
Solution Approach 1:
The patent segments the signaling procedures by creating a simplified SDT-specific signaling path for small data transmissions. This separates SDT signaling from general RRC connection setup signaling, reducing the overhead for small data by eliminating redundant connection establishment messages.
Solution Approach 2:
The patent applies partial action by implementing a reduced signaling procedure for SDT compared to full RRC connection setup. The SDT configuration enables transmission with minimal signaling, performing only the necessary actions for small data while omitting unnecessary connection establishment steps.
3Loss of time
If the SDT-specific timer is started or restarted upon BSR triggering, then transmission timing control is improved, but device complexity increases
Solution Approach 1:
The patent implements preliminary action by pre-configuring the SDT-specific timer parameters and BSR triggering conditions before actual data transmission. This allows the UE to have pre-established timing control mechanisms ready, enabling rapid response when small data needs to be transmitted without complex real-time calculations.
Solution Approach 2:
The patent implements feedback mechanisms through the BSR (Buffer Status Report) system that monitors data buffer status and triggers appropriate timer actions. This feedback loop provides automatic timing control based on actual buffer conditions, simplifying the overall control logic while maintaining precise timing management.
Data Source
AI summary
A method for a user equipment (UE) to perform small data transmission (SDT) is provided. The method includes receiving, from a base station (BS), system information that includes an SDT configuration, the SDT configuration including an SDT-specific timer; initiating an SDT procedure when the UE is in a radio resource control (RRC) inactive (RRC_INACTIVE) state; triggering a Buffer Status Report (BSR) during the SDT procedure; and starting or restarting the SDT-specific timer in response to triggering the BSR.