QoS-Flow Small Data Transmission for Inactive-State Downlink
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Solution Overview
Problem
Current communication protocols lack a solution for mobile terminated small data transmission (MT SDT) in terminal devices, leading to unnecessary power consumption and signaling overheads when devices transition to a connected state for downlink data reception.
Innovation Solution
Implement methods and apparatuses in access network devices and elements to support MT SDT by determining data transmission based on quality of service (QoS) flow sizes, using signaling radio bearers (SRB2) for control signaling, and optimizing eDRX cycles to enable efficient small data transmission without entering a connected state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal device enters a connected state to receive downlink small data, then data reception can be achieved, but power consumption increases
Solution Approach 1:
The network side performs preliminary actions by determining data size before transmission and configuring the terminal device with appropriate parameters in advance, enabling the terminal to receive data while remaining in inactive state without needing to transition to connected state
Solution Approach 2:
The patent changes the parameter of RRC state configuration by introducing a new parameter configuration that allows the terminal device to receive downlink data in inactive state, fundamentally altering the state transition requirement and enabling energy saving
2Productivity
If the terminal device transitions to connected state for MT SDT, then downlink data transmission is enabled, but signaling overheads increase
Solution Approach 1:
The patent extracts the essential function of MT SDT from the connected state requirement, separating data transmission capability from the need for RRC connection establishment, thereby eliminating unnecessary signaling overheads while maintaining downlink data transmission functionality
Solution Approach 2:
The patent makes the inactive state multi-functional by enabling it to support both uplink and downlink small data transmission, eliminating the need for separate connected state and reducing signaling overheads associated with state transitions
3Ease of manufacture
If the access network device transmits data without QoS flow size information, then transmission simplicity is maintained, but unnecessary data transmission occurs
Solution Approach 1:
The access management network element performs preliminary action by determining the data size of QoS flow before transmission, enabling the access network device to transmit only necessary data while maintaining simple transmission procedures
Solution Approach 2:
The patent applies partial action by transmitting only the necessary portion of data based on QoS flow size information, avoiding excessive or unnecessary data transmission while maintaining transmission simplicity through automated size-based selection
Data Source
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AI summary
Embodiments of this application provide a small data transmission method and a communication apparatus. In the method, an access management network element may provide a data size for an access network device at a granularity of a QoS flow, so that the access network device can determine to transmit data of the QoS flow in an SDT manner. In this way, MT SDT can be supported, to help a terminal device save energy. In addition, transmission of a size of unnecessary data can be avoided, that is, unnecessary signaling overheads can be avoided, to save transmission resources.