Small Data Transmission Mobility During Cell Reselection
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Solution Overview
Problem
Existing communication systems face challenges in handling cell reselection during small data transmission (SDT) procedures for terminal devices in an inactive state, leading to unnecessary signaling overhead, power consumption, and loss of already transmitted data due to transitions to idle states.
Innovation Solution
A solution for mobility during SDT procedures involves a terminal device in an inactive state transmitting information indicating an intention of cell reselection to the network device, allowing the network device to maintain context information and data, enabling seamless transitions to either inactive or connected states to avoid idle states and data loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the terminal device transitions to idle state during cell reselection, then the device can perform cell reselection, but data loss and latency occur due to loss of context information
Solution Approach 1:
The terminal device transmits an indication of intention to perform cell reselection before actually transitioning to idle state. This preliminary notification allows the network device to prepare and maintain context information, preventing data loss when the terminal eventually moves to idle state for cell reselection.
Solution Approach 2:
The indication message serves as an intermediary communication between the terminal device and network device. It bridges the gap between the terminal's intention to reselect cells and the network's need to maintain context information, enabling coordinated state transitions without information loss.
2Use of energy by moving object
If the terminal device remains in inactive state during SDT procedure, then power consumption is reduced, but cell reselection cannot be performed
Solution Approach 1:
The terminal device dynamically transitions from inactive state to idle state temporarily for cell reselection, then returns to inactive state. This dynamic state management allows the device to maintain low power consumption while periodically enabling cell reselection capability when needed during the SDT procedure.
3Loss of information
If the terminal device transitions to connected state for cell reselection, then context information is maintained, but signaling overhead and power consumption increase
Solution Approach 1:
Instead of fully transitioning to connected state, the terminal device performs a partial state transition to idle state only when needed for cell reselection. This partial action maintains context information sufficient for SDT while avoiding the full overhead and power consumption of connected state.
Data Source
AI summary
Embodiments of the present disclosure relate to mobility for small data transmission (SDT) procedure. The first device, which is in an inactive state and served in a first cell of the second device, performs a session of small data transmission between the first device and the second device. The first device determines whether a potential cell reselection criterion is satisfied when the session of small data transmission is ongoing. If a potential cell reselection criterion is satisfied, the first device transmits, to the second device, first information indicating an intention of cell reselection. As such, if the cell reselection happens during SDT procedure, the second device is able to put the first device into either the inactive state or the connected state. Accordingly, already transmitted data is not lost in case cell reselection happens before the session of small data transmission is completed.