Pre-allocated Uplink Grant Release for Seamless Handover
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Solution Overview
Problem
Inter-system mobility between LTE and NR/NextGen systems is challenging, requiring seamless service continuity for user equipment moving between the two systems, particularly in handling pre-allocated uplink grants during handovers or secondary cell group changes.
Innovation Solution
A communication device with a processing circuit and storage unit that uses temporary identities to manage pre-allocated uplink grants, releasing them upon failure to prevent interference and ensure smooth handovers or secondary cell group changes without random access procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-allocated uplink grant is configured for handover to enable seamless service continuity, then service continuity is improved, but transmission interference may occur if the grant is not properly released upon handover failure
Solution Approach 1:
The patent implements a feedback mechanism where the UE monitors handover execution status and provides feedback by releasing the pre-allocated UL grant when handover failure is detected. This feedback loop ensures that the network side is aware of the grant release status, preventing transmission interference while maintaining service continuity through proper resource management.
Solution Approach 2:
The patent changes the state parameter of the pre-allocated UL grant from 'allocated' to 'released' based on handover execution status. When handover failure is detected, the grant configuration parameter is modified to release the resource, thereby eliminating potential transmission interference while preserving the grant for successful handover scenarios.
2Speed
If a pre-allocated uplink grant is used to avoid random access procedures during handover, then handover speed is improved, but resource management complexity increases due to the need to track and release grants upon failure
Solution Approach 1:
The patent applies self-service by enabling the UE to autonomously manage the pre-allocated UL grant resources. The UE independently monitors handover status, detects failures, and releases grants without requiring explicit network commands for each release operation. This self-service approach simplifies overall resource management while maintaining fast handover performance.
3Reliability
If the pre-allocated uplink grant is maintained during handover attempts, then uplink transmission capability is preserved, but resource waste occurs if the grant remains allocated after failed handover
Solution Approach 1:
The patent implements discarding and recovering by releasing (discarding) the pre-allocated UL grant when handover failure is detected, preventing resource waste. The grant configuration is recovered or re-allocated by the network for subsequent handover attempts or other uses, ensuring efficient resource utilization while maintaining uplink transmission capability when needed.
Data Source
AI summary
A communication device for handling a pre-allocated uplink (UL) grant comprises a storage device and a processing circuit, coupled to the storage device. The storage device stores, and the processing circuit is configured to execute instructions of: using a first temporary identity to perform a data communication with a first base station (BS) via a first cell; receiving a handover command from the first BS, wherein the handover command configures the pre-allocated UL grant and configures the communication device to perform a handover to a second cell; and releasing the pre-allocated UL grant in response to a failure, when detecting the failure before completing the handover to the second cell.