Timing Advance Command for Uplink Transmission in 5G
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Solution Overview
Problem
In 5G communication systems, user equipment (UE) configured with a grant to transmit data in RRC_IDLE or RRC_INACTIVE states can only use the grant when uplink timing is aligned with the network, and this alignment is not continuously maintained, leading to potential disruptions in data transmission.
Innovation Solution
A method where a wireless device stays in the RRC connected state to receive and adapt timing advance information during paging occasions, allowing continuous data transmission with the configured grant by periodically aligning uplink timing with the network, thereby reducing the need for new grant configurations and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the UE uses configured grant for data transmission in RRC_IDLE or RRC_INACTIVE states, then data transmission capability is improved, but uplink timing alignment cannot be continuously maintained leading to transmission disruptions
Solution Approach 1:
The network sends Timing Advance Commands to the UE periodically through paging messages while the UE is in RRC_IDLE or RRC_INACTIVE state. This periodic timing alignment mechanism ensures that the UE's uplink timing remains synchronized with the network without requiring continuous connection, thereby maintaining both data transmission capability and timing alignment reliability.
2Reliability
If the UE maintains continuous RRC connected state for timing alignment, then uplink timing alignment is improved, but power consumption increases
Solution Approach 1:
Instead of maintaining continuous connection, the UE transitions to RRC_IDLE or RRC_INACTIVE state and receives timing alignment information periodically through paging messages. This approach maintains sufficient timing alignment reliability while significantly reducing power consumption compared to continuous connected state.
Solution Approach 2:
The UE autonomously adapts its uplink timing based on the Timing Advance Command received in the paging message, without requiring network-controlled connection management. This self-service mechanism allows the UE to maintain timing alignment independently in idle/inactive states, reducing the need for continuous network interaction and lowering power consumption.
3Ease of operation
If the UE stays in RRC connected state to receive timing advance, then timing advance adaptation is improved, but the need for frequent new grant configurations increases
Solution Approach 1:
The timing advance adaptation function is extracted from the RRC connected state and made available in RRC_IDLE or RRC_INACTIVE states through paging messages. This allows the UE to adapt timing advance without requiring full connection establishment, thereby improving ease of operation while reducing the frequency of new grant configurations needed.
Data Source
AI summary
Provided are a method for skipping contention resolution. According to an embodiment of the present disclosure, the method includes leaving radio resource control (RRC) connected state, while leaving RRC connected state, receiving information on timing advance in a paging occasion, adapting the timing advance and performing transmission based on the adapted timing advance.