Handover Error Correction in Wireless Communication Systems
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Solution Overview
Problem
The LTE system faces challenges in handling handover failures and handovers to CSG cells shared by multiple operators, where existing methods fail to recover parameters correctly and determine operator IDs for successful handovers.
Innovation Solution
A method is proposed to store and reset the COUNT value (HFN + PDCP SN) for encryption and integrity verification during handover failures, and to report operator IDs when handover to a CSG cell shared by multiple operators, enabling successful communication by determining accessible cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the full configuration option is applied during handover, then the target cell can be configured with complete new settings, but the existing parameters are reset and cannot be reused when handover fails
Solution Approach 1:
The patent applies preliminary action by storing the COUNT value (HFN + PDCP SN) before resetting it during handover with full configuration option. This allows the original parameter to be recovered if handover fails, enabling parameter reuse and avoiding the need to reset parameters permanently. The stored parameter is retrieved when connection reestablishment is needed.
2Adaptability or versatility
If the user equipment reports CSG ID and member indication for single-operator CSG cells, then handover to CSG cells can be managed, but the scheme does not specify how to report operator ID for multi-operator CSG cells
Solution Approach 1:
The patent applies local quality by differentiating the reporting mechanism based on the operator configuration of the target CSG cell. For single-operator CSG cells, the existing CSG ID and member indication are reported. For multi-operator CSG cells, the user equipment additionally reports the operator ID to identify which operator's CSG cell is being accessed, enabling the network to properly handle handover to shared cells.
Data Source
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AI summary
The present disclosure provides a method for correcting an error caused by Hyper Frame Number (HFN) and Packet Data Convergence Protocol Sequence Number (PDCP SN) mismatch between a user equipment and base station when the user equipment fails in handover between cells in a wireless communication system. In addition, the present disclosure provides a handover procedure for a user equipment performing handover from a macro cell to a Closed Subscriber Group (CSG) cell shared by multiple operators in a wireless communication system. The present disclosure enables a user equipment and base station to perform communication without a malfunction after handover failure. For handover from a macro cell to a CSG cell shared by multiple operators, the present disclosure enables a user equipment to perform handover to an accessible cell.