Terminal Device Idle-to-Connected Mode Latency Reduction
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Solution Overview
Problem
Current 4G technologies face high latency when switching from an idle mode to a connected mode in 5G communication systems, particularly due to the need for a random access process to obtain a timing advance value, which hinders the achievement of the 10 ms control-plane target latency required for ultra-reliable and low-latency communications.
Innovation Solution
A data communication method where a terminal device prestores a timing advance indication list of cells, allowing it to directly send an uplink Radio Resource Control message without random access, using the stored TA value to reduce latency during mode switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a random access process is performed to obtain a TA value before sending an RRC connection resume request message, then uplink signal synchronization is ensured, but control-plane latency increases
Solution Approach 1:
The terminal device prestores a TA indication list of a group of cells before entering idle mode. When resuming connection, the terminal queries this pre-stored list to obtain the TA value without performing a random access process, thereby eliminating the time-consuming random access step while ensuring synchronization is maintained through the pre-acquired TA value
Solution Approach 2:
The terminal device uses a copied or pre-acquired TA value from the pre-stored TA indication list instead of obtaining a fresh TA value through random access. This copying approach allows the terminal to reuse valid TA information from the list, avoiding the need to repeat the synchronization acquisition process
2Reliability
If the UE switches from idle state to connected mode using traditional RRC connection setup, then a reliable connection is established, but the switching latency is relatively high
Solution Approach 1:
The terminal device prestores a TA indication list of a group of cells before entering idle mode. When resuming connection, the terminal queries this pre-stored list to obtain the TA value without performing a random access process, thereby eliminating the time-consuming random access step while ensuring synchronization is maintained through the pre-acquired TA value
Solution Approach 2:
The system dynamically adapts the connection resumption process based on whether the terminal has a pre-stored TA indication list. When the list is available, the terminal uses the optimized random-access-free path; when not available, it falls back to the traditional random access path, making the system flexible and adaptive to different conditions
Data Source
AI summary
The present disclosure discloses a data communication method and a device, to resolve a prior-art problem of a high latency for switching a terminal device from an idle mode to a connected mode. The method includes: prestoring, by a terminal device, a TA indication list of a group of cells; performing, by the terminal device, cell selection or reselection, and obtaining a cell identity of a cell obtained after the selection or reselection; querying, by the terminal device based on the cell identity, the TA indication list of the group of cells for a TA value corresponding to the cell identity; and if the terminal device successfully finds, in the TA indication list of the group of cells, the TA value corresponding to the cell identity, sending, by the terminal device, an uplink Radio Resource Control (RRC) message in a random access-free manner.