RRC Inactive Small Data Transmission for Paging-Triggered Uplink
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Solution Overview
Problem
In wireless communication systems, the transition between RRC_INACTIVE and RRC_CONNECTED states for small data transmission incurs significant signaling overhead and power consumption, particularly for small data services with low transmission frequency, which is inefficient and costly.
Innovation Solution
Implementing downlink-triggered Small Data Transmission (SDT) in RRC_INACTIVE state, where the UE determines the availability of uplink data after receiving a paging message, allowing for data transmission in RRC_INACTIVE state without transitioning to RRC_CONNECTED, thereby reducing signaling overhead and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE enters RRC_CONNECTED state for data transmission, then the data transmission can be performed, but the signaling overhead increases and power consumption increases
Solution Approach 1:
The patent segments data transmission into two modes: Small Data Transmission (SDT) for small data packets and conventional RRC_CONNECTED transmission for large data. The UE determines the data size and selects the appropriate transmission mode, avoiding unnecessary state transitions for small data and reducing power consumption while maintaining productivity.
Solution Approach 2:
The patent introduces dynamic state selection where the UE can flexibly choose between RRC_INACTIVE and RRC_CONNECTED states based on real-time data characteristics. The UE autonomously determines whether to perform SDT or transition to RRC_CONNECTED by evaluating data size, buffer status, and SDT configuration, creating a dynamic adaptation mechanism that optimizes power consumption for different transmission scenarios.
2Productivity
If the UE performs RRC state switching for data transmission, then data can be transmitted, but the signaling overhead becomes greater than the transmission overhead
Solution Approach 1:
The patent segments the data transmission process into SDT mode and conventional mode based on data size thresholds. For small data, SDT is used which minimizes signaling overhead by allowing transmission in RRC_INACTIVE state without full RRC state transition. For large data, conventional RRC_CONNECTED transmission is used. This segmentation ensures signaling overhead never exceeds transmission overhead by selecting the appropriate mode.
Solution Approach 2:
The patent changes the transmission parameter (state mode) based on data characteristics. The UE evaluates data size, buffer status, and SDT configuration parameters to determine the optimal transmission mode. By dynamically adjusting the transmission parameter between SDT and RRC_CONNECTED based on real-time conditions, the system ensures signaling overhead remains efficient relative to transmission overhead.
3Productivity
If the UE triggers SDT upon receiving paging message, then downlink data can be transmitted, but uplink non-small data may arrive causing conflict
Solution Approach 1:
The patent implements a feedback mechanism where the UE continuously monitors its data buffer status after receiving a paging message. If uplink non-small data arrives or downlink data size exceeds the SDT threshold, the UE provides feedback by transitioning to RRC_CONNECTED state. This feedback ensures the system adapts to actual data conditions, maintaining productivity for downlink transmission while achieving versatility in handling both uplink and downlink data scenarios.
Solution Approach 2:
The patent creates a dynamic decision mechanism where the UE evaluates data characteristics in real-time after receiving paging messages. The UE determines whether to proceed with SDT or transition to RRC_CONNECTED based on uplink data arrival, downlink data size, and buffer status. This dynamic adaptation enables the system to handle both downlink-triggered scenarios and uplink data arrivals effectively, achieving both productivity and versatility.
4Loss of energy
If the UE maintains RRC_INACTIVE state for small data transmission, then power consumption is reduced, but access delay increases when transitioning to RRC_CONNECTED
Solution Approach 1:
The patent segments data transmission into small data (SDT) and large data (RRC_CONNECTED) categories. For small data, the UE remains in RRC_INACTIVE state and performs SDT, avoiding the access delay associated with state transitions while maintaining low power consumption. For large data requiring RRC_CONNECTED state, the segmentation ensures the transition is necessary and optimized. This segmentation resolves the contradiction by eliminating unnecessary transitions for small data.
Solution Approach 2:
The patent enables preliminary configuration of SDT parameters and resources while the UE is in RRC_INACTIVE state. The network pre-configures SDT thresholds, data size limits, and transmission parameters before the UE needs to transmit data. This preliminary action allows the UE to quickly perform SDT without delay when small data needs to be transmitted, maintaining both low power consumption and fast access by having everything prepared in advance.
Data Source
AI summary
The present application provides a method and device for wireless communications. A first node receives a first paging message; as a response to receiving the first paging message, executes a first procedure, and the behavior of executing a first procedure comprises transmitting a first message; wherein the first paging message instructs a first radio bearer executing data transmission in RRC_INACTIVE state; the first message at least comprises a CCCH message; whether a first condition set is met is used to determine whether a first sub-message is comprised in the first message, when all conditions in the first condition set are met, the first message does not comprise the first sub-message; when any condition in the first condition set is not met, the first message comprises the first sub-message. The present application effectively supports downlink-triggered Small Data Transmission (SDT).