Configured-Grant Uplink for Inactive-State Small Data Transmission
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Solution Overview
Problem
In inactive states of terminal devices, existing technologies face challenges in supporting small and infrequent data transmission, leading to unnecessary power consumption and signaling overhead due to the need to resume connection for downlink and uplink data, which is addressed by 3GPP Release 17's small data transmission (SDT) feature.
Innovation Solution
Implementing configured grant (CG) based SDT, including bandwidth part (BWP) configuration, contention resolution, and backoff mechanisms to facilitate data transmission without RRC messages, utilizing dedicated or shared CG resources, and managing contention through timers and indicators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the terminal device transmits uplink data in connected state, then the data transmission can be performed, but the power consumption and signaling overhead increase unnecessarily
Solution Approach 1:
The patent segments the data transmission process by introducing two distinct transmission paths: one for connected state and another for inactive state. The terminal device can select the inactive state path for small data transmissions, separating this from the traditional connected state path. This segmentation allows optimized resource usage and reduced power consumption for small data packets while maintaining the connected state path for larger or more critical transmissions.
Solution Approach 2:
The patent applies preliminary action by pre-configuring uplink resources and grant configurations while the terminal device is in inactive state. The network device pre-allocates physical uplink shared channel (PUSCH) resources and configures grant parameters in advance, so when small data needs to be transmitted, the terminal can immediately use these pre-configured resources without transitioning to connected state, thereby reducing power consumption and signaling overhead.
2Loss of information
If the terminal device transmits uplink data in inactive state using configured grant, then the signaling overhead is reduced, but resource allocation complexity increases
Solution Approach 1:
The patent implements self-service by enabling the terminal device to autonomously select and use pre-configured grant resources from the inactive state without requiring real-time network scheduling or RRC message exchanges. The terminal independently determines whether to transmit small data in inactive state using the configured grant, self-manages the transmission process, and only transitions to connected state if necessary. This self-service approach significantly reduces signaling overhead and network device involvement for small data transmissions.
3Productivity
If multiple terminal devices share configured grant resources, then the resource utilization efficiency improves, but contention between devices increases
Solution Approach 1:
The patent introduces feedback mechanisms for contention resolution when multiple terminal devices share configured grant resources in inactive state. The network device monitors the shared resources and provides feedback through downlink control information or random access responses to resolve conflicts between devices. This feedback loop allows multiple devices to efficiently share resources while maintaining reliability through coordinated contention resolution, balancing resource utilization with transmission success rates.
Data Source
AI summary
Embodiments of the present disclosure relate to methods, devices and computer readable media for communication. A network device transmits, to a terminal device, a configuration of bandwidth part for transmission of uplink data in an inactive state, the configuration comprising a configured grant. When the terminal device decides to transmit the uplink data in the inactive state, the terminal device determines the configured grant from the configuration of bandwidth part, and transmits, in the inactive state, the uplink data to the network device based on the configured grant. In this way, configuration grant based small data transmission can be enhanced.