RACH-less SeNB Change via MAC Message for Handover Delay Reduction
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Solution Overview
Problem
Conventional wireless communication systems require a Time Advance (TA) determination during handovers, which increases the time required to complete the handover procedure, especially when TA does not need to be determined, and involve a Random-Access Channel (RACH) procedure that can be time-consuming.
Innovation Solution
Implementing a RACH-less Secondary Base Station (SeNB) Change procedure in Dual Connectivity systems, where the UE device requests a Media Access Control (MAC) message from the Target SeNB, including TA information if needed, to determine when the handover is complete, without performing the RACH procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the RACH procedure is performed during handover, then Timing Advance can be determined, but handover delay increases
Solution Approach 1:
The patent extracts the Timing Advance determination from the RACH procedure by having the target base station calculate TA independently based on uplink signals received during handover, eliminating the need for the UE to perform RACH with the target base station
Solution Approach 2:
The target base station performs preliminary TA calculation by analyzing uplink signals received during the handover process before the UE needs to synchronize transmissions, preparing the timing advance value in advance
2Stability of the object's composition
If the RACH procedure is performed during SeNB Change, then uplink synchronization is achieved, but procedure time increases
Solution Approach 1:
The patent removes the RACH procedure from the SeNB Change process by having the target SeNB determine TA independently through analyzing uplink signals, achieving synchronization without the traditional RACH exchange
Solution Approach 2:
The patent uses an intermediary approach where the source base station or network controller facilitates the TA determination process, allowing the target SeNB to obtain timing advance information without direct RACH interaction from the UE
Data Source
AI summary
The examples described herein provide for a Secondary Base Station (SeNB) Change procedure in a system configured to provide Dual Connectivity, where the SeNB Change procedure does not include the RACH procedure. As part of the SeNB Change procedure, a UE device generates a request that the Target Secondary base station (Target SeNB) is to send a Media Access Control (MAC) message to the UE device. In some examples, the request can be configured to specify a particular MAC Control Element that the Target SeNB should send in response to receiving the request. Upon receipt of the request, the Target SeNB transmits the requested MAC message to the UE device, along with TA information, if required. The UE device determines when the SeNB Change procedure has been completed, based at least partially on when the requested MAC message is received from the Target SeNB.