5G Cell Switching with Early TA Acquisition and Collision Handling
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Solution Overview
Problem
Current 3GPP 5G technology does not address issues of timing advance (TA) acquisition failure and preamble transmission collision in lower layer-based mobility scenarios.
Innovation Solution
Implement methods and apparatuses for UE, BS-CU, BS-DU, and BS to manage TA acquisition and re-acquisition procedures, including early TA acquisition and re-acquisition, handling collisions, and transmitting preambles with varying power levels to ensure successful cell switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs TA acquisition procedure before cell switching, then the timing advance is acquired for the target cell, but processing delay increases due to the additional procedure
Solution Approach 1:
The patent performs TA acquisition procedure in advance before cell switching is executed. The UE receives RRC configuration information for candidate cells, performs TA acquisition to obtain timing advance values, and stores them for later use during actual cell switching, thereby avoiding delay during the switching moment
Solution Approach 2:
The patent proactively acquires TA before cell switching to prevent potential TA acquisition failure during switching. By obtaining TA in advance when channel conditions are more favorable, the system anticipates and mitigates the risk of TA acquisition failure that could occur if attempted during the critical switching phase
2Reliability
If the UE transmits preamble for TA acquisition, then the TA value can be obtained, but collision with UL transmission in serving cell may occur
Solution Approach 1:
The patent introduces a collision detection and resolution mechanism as an intermediary layer. The UE checks for conflicts between scheduled UL transmissions in the serving cell and preamble transmissions for TA acquisition, and resolves collisions by adjusting transmission timing or prioritizing critical transmissions, thereby preventing harmful interference
Solution Approach 2:
The patent dynamically adjusts the UE's transmission behavior based on real-time collision detection. When a collision is detected between UL transmission and preamble transmission, the system adaptively modifies transmission parameters such as timing, power, or sequence selection to resolve the conflict and ensure successful TA acquisition without interfering with ongoing communications
3Reliability
If the UE suspends the first RA procedure to perform TA acquisition, then the TA is acquired for the candidate cell, but the original RA procedure delay increases
Solution Approach 1:
The patent performs TA acquisition as a preliminary action before cell switching, during which the UE is already in a connected state with the serving cell. This timing allows TA acquisition to occur in parallel with normal RA procedures or during idle periods, minimizing impact on RA procedure duration while ensuring TA is ready for swift cell switching
Data Source
AI summary
Embodiments of the present application relate to methods and apparatuses for lower layer-based mobility with timing advance (TA) acquisition failure and preamble transmission collision under a 3rd Generation Partnership Project (3GPP) 5G system or the like. According to an embodiment of the present application, a candidate distributed unit (DU) of a base station (BS) includes a transceiver and a processor coupled to the transceiver, and the processor is configured to cause the candidate DU to: receive a request of a cell switching procedure associated with a candidate cell from a centralized unit (CU) of the BS; and transmit a response including configuration information associated with the candidate cell to the CU based on the request.