LTE Handover MIB SIB Decoding Timer Logic
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Solution Overview
Problem
In LTE handover procedures, user equipment (UE) often experiences radio link failures due to inability to decode Master Information Blocks (MIB) or System Information Blocks (SIB) within a specific time frame, especially in poor coverage conditions, leading to VoLTE call failures.
Innovation Solution
The UE determines a decoding timer value based on network conditions and attempts to decode MIB or SIB from the target cell within this time frame; if not decoded, it triggers a radio link failure. Additionally, if the target cell is the same as the source cell, the UE skips decoding MIB/SIB attempts, using previously received information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the UE attempts to decode MIB/SIB within a fixed time frame after handover, then the handover procedure is completed quickly, but radio link failures occur in poor coverage conditions
Solution Approach 1:
The patent makes the decoding timer dynamic rather than fixed. The timer value is adjusted based on handover type (intra-eNB or inter-eNB) and can be extended under specific conditions such as TTI bundling activation or poor coverage detection. This allows the system to adapt the decoding time to actual network conditions, resolving the contradiction between fast handover completion and reliable decoding in challenging environments.
2Ease of operation
If the UE performs MIB/SIB decoding after every handover, then the system follows standard procedure, but unnecessary radio link failures are triggered when target cell is the same as source cell
Solution Approach 1:
The patent performs a preliminary check to determine whether the target cell is the same as the source cell before initiating MIB/SIB decoding. When the cells are identical, the UE reuses previously received system information from the source cell, avoiding redundant decoding attempts and preventing unnecessary radio link failures. This preliminary identification action resolves the contradiction by maintaining standard procedure compliance while eliminating futile operations.
3Reliability
If the UE uses a longer decoding timer to allow sufficient decoding time, then decoding success improves in poor coverage, but handover completion time increases
Solution Approach 1:
The patent segments the handover procedure into distinct phases with different timer requirements. For intra-eNB handovers, a shorter timer is used since the cell remains the same. For inter-eNB handovers or when TTI bundling is detected, the timer is extended. This segmentation allows the system to optimize between speed and reliability based on the specific handover scenario, resolving the time-reliability contradiction.
Data Source
AI summary
A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus performs a handover from a source cell to a target cell. The apparatus determines a decoding timer value based on network conditions. The apparatus attempts to decode a MIB or a SIB from the target cell within a time after the handover corresponding to the decoding timer value. The apparatus triggers a radio link failure (RLF) when the MIB or the SIB is not decoded within the time corresponding to the decoding timer value.