Configured Grant Transmission Timing for Small Data Uplinks
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Solution Overview
Problem
Existing communication systems face delays and inefficiencies in selecting configured grant (CG) transmissions for small data due to lengthy evaluation procedures and potential failures in timing advance alignment, particularly when CG periodicity is large, leading to delays and potential failures in selecting the appropriate transmission type.
Innovation Solution
A method where a device determines the validity of timing advance and evaluates conditions in advance for subsequent CG occasions, allowing for timely and successful small data transmissions by selecting CG-based or random access (RA)-based SDT based on these criteria.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the device performs evaluation of timing advance validity and transmission type selection at the time of data transmission, then the transmission decision is made based on current conditions, but delays occur particularly when CG periodicity is large
Solution Approach 1:
The device performs evaluation of timing advance validity and determines transmission type (CG-based or RA-based SDT) in advance before the actual data transmission occasion. This preliminary evaluation ensures that when the data arrives for transmission, the device already has a determined transmission type, avoiding delays caused by real-time evaluation especially when CG periodicity is large.
2Loss of time
If the device uses configured grant resources for small data transmission, then packet transmission delay is eliminated, but timing advance misalignment may cause transmission failures
Solution Approach 1:
The device evaluates the validity of timing advance before utilizing configured grant resources for small data transmission. By performing this evaluation in advance, the device ensures that the timing advance is still valid when the transmission occurs, preventing transmission failures due to timing misalignment while maintaining the low-latency benefits of configured grant transmission.
Solution Approach 2:
The device uses feedback from the network regarding timing advance validity to determine whether to proceed with configured grant transmission. This feedback mechanism allows the device to adjust its transmission strategy based on current timing conditions, ensuring reliable transmission by avoiding use of configured grant resources when timing advance has expired or become invalid.
3Productivity
If multiple terminal devices share periodic configured grant resources, then resource utilization ratio increases, but collision and interference between devices may occur
Solution Approach 1:
Each terminal device performs preliminary evaluation of timing advance validity and determines its transmission type before the actual transmission occasion. This advance determination ensures that when multiple devices share periodic configured grant resources, each device has already verified its timing alignment status, reducing the likelihood of collisions and interference while maintaining high resource utilization through shared periodic resources.
Data Source
Figure 1A~1B
Figure 1C
Figure 2
AI summary
Mechanism on configured grant transmissions is provided. If a small data transmission is needed, a first device determines whether a timing advance is valid in a subsequent CG occasion for the small data transmission. The first device also determines whether an evaluation of a validity condition is applicable in the subsequent CG occasion for the small data transmission. If the timing advance is valid and the evaluation is applicable, the first device performs the small data transmission in the subsequent CG occasion. In this way, the first device is able to perform the evaluation of the validity condition in advance, thereby reducing delays and avoiding failures.