Pre-configuring Timing Advance for Cellular Handover
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Solution Overview
Problem
The existing handover process in cellular wireless networks is delayed due to the time-consuming random-access process for determining timing advance, which can lead to connectivity loss and resource collisions, especially when multiple UEs attempt to access the network simultaneously.
Innovation Solution
The source base station transmits a measurement request to the target base station to evaluate the UE's uplink reference signal, allowing the target base station to determine and report the timing advance, which is then provided to the UE, thereby bypassing the random-access process for establishing timing advance during handover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the random-access process is used to determine timing advance during handover, then the UE can establish synchronization with the target base station, but the handover process becomes delayed and connectivity loss occurs
Solution Approach 1:
The source base station performs preliminary actions by requesting the target base station to evaluate the UE's uplink reference signal and determine timing advance before the actual handover occurs. This preliminary determination of timing advance parameters allows the UE to be pre-configured with the necessary synchronization information, eliminating the need for time-consuming random-access procedures during handover and thus reducing handover delay while maintaining connectivity reliability.
2Reliability
If the random-access process is used for timing advance determination, then timing synchronization is achieved, but resource collisions occur when multiple UEs access simultaneously
Solution Approach 1:
The system performs preliminary evaluation of the UE's uplink reference signal at the target base station before handover occurs. By determining the timing advance parameter in advance based on the evaluated reference signal, the system avoids the need for multiple UEs to simultaneously access the random-access channel, thereby preventing resource collisions while ensuring accurate timing synchronization for each UE.
Solution Approach 2:
The source base station acts as an intermediary that facilitates the timing advance determination process. It requests the target base station to evaluate the UE's uplink reference signal and provides the determined timing advance information to the UE during handover. This intermediary mechanism eliminates direct random-access interactions between multiple UEs and the target base station, preventing resource collisions while maintaining synchronization reliability.
3Adaptability or versatility
If the existing handover process is used, then UE can transition between base stations, but the process is complex and time-consuming
Solution Approach 1:
The source base station performs preliminary actions by requesting the target base station to evaluate the UE's uplink reference signal and determine timing advance before handover. This pre-determination of timing parameters simplifies the actual handover execution, as the UE only needs to apply the pre-configured timing advance information rather than undergoing the complete random-access procedure, thus reducing procedural complexity while maintaining handover adaptability.
Solution Approach 2:
The invention extracts the timing advance determination function from the random-access process and performs it separately through the source base station's request to the target base station. By separating this function, the handover procedure is simplified as the UE only needs to receive and apply the pre-determined timing advance information, eliminating the need for complex random-access interactions and reducing overall procedural complexity.
Data Source
AI summary
A method and system for pre-configuring a UE with timing advance for use in communication with a handover target. When a UE is being served by a handover source, the handover source transmits to a handover target a measurement request that specifies an uplink reference signal that the UE will provide, and the handover target evaluates that uplink reference signal to determine a timing advance for the UE and reports the timing advance in a response to the handover source. As the handover source then directs the UE to hand over to the handover target, the handover source provides the UE with an indication of the timing advance provided by the handover target. The UE may then transition to be served by the handover target and to make use of the indicated timing advance.