Cell Selection Offset for Wireless System Information Failure
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Solution Overview
Problem
In wireless communication systems, user equipment (UE) continues to perform RACH procedures at the edge of a cell until system information is received, leading to increased uplink interference when the requested system information is not received promptly.
Innovation Solution
The UE applies an offset to the cell selection or reselection criteria, temporarily adjusting the RX level and quality values to prioritize cell reselection and stop requesting system information from the current cell, thereby reducing continuous RACH access and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE continues to perform RACH procedures at the same cell until system information is received, then the UE ensures it obtains the requested system information, but uplink interference increases due to continuous RACH access at cell edge
Solution Approach 1:
The patent applies dynamics by making the cell selection criteria adjustable through an offset parameter. When RACH failure is detected, the network dynamically modifies the cell selection criterion by applying an offset (Qoffsetfailure) to the RX level and quality values, enabling the UE to dynamically switch from persistent RACH attempts to cell reselection based on changed conditions
Solution Approach 2:
The patent changes the cell selection parameter by introducing Qoffsetfailure, which modifies the RX level (Qrxlevmin) and quality (Qqualmin) thresholds. This parameter change makes the cell less attractive for selection when RACH failures occur, thereby reducing continuous RACH access and associated uplink interference while maintaining system information acquisition through reselection to other cells
2Reliability
If the UE performs multiple RACH retries for SI request, then the probability of receiving system information increases, but the time consumed and uplink interference increase
Solution Approach 1:
The patent implements dynamic behavior where the UE adapts its access strategy based on RACH failure detection. Instead of statically continuing RACH retries, the system dynamically transitions to cell reselection when failures are detected, optimizing the balance between maintaining SI acquisition probability and reducing time consumption
Solution Approach 2:
The patent applies skipping by allowing the UE to bypass continued RACH retries at the failed cell and rush through to alternative cells for SI acquisition. This跳过机制 enables the UE to quickly move on from problematic cells, reducing the time spent on unsuccessful RACH procedures while maintaining the ability to obtain system information through reselection
Data Source
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AI summary
Provided are a method for a user equipment (UE) to perform a cell reselection in a wireless communication, and an apparatus supporting the same. The method may include: camping on a cell of a base station; initiating a SI request procedure to the base station via the cell; if the initiated system information (SI) request procedure is failed, performing the cell reselection by applying a failure offset to the cell.