Cell Reselection via Intermediate Camping to Reduce Signaling
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Solution Overview
Problem
In wireless communication systems, cell reselection processes often result in 'double cell reselection' due to unknown cell reselection parameters, leading to inefficient signaling and potential interference, especially during inter-frequency mobility.
Innovation Solution
A user equipment (UE) initially camps on a first cell, moves to a second cell without reselecting, and updates rankings based on obtained cell reselection parameters, avoiding uplink transmission until rankings are updated to determine the best cell for reselection, thereby avoiding double cell reselection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the UE performs cell reselection to a better cell without obtaining cell reselection parameters first, then the UE can quickly move to a better cell, but the UE may perform double cell reselection and cause unnecessary signaling and interference
Solution Approach 1:
The UE performs preliminary actions by moving to the second cell and obtaining cell reselection parameters before finalizing the cell reselection decision. This preliminary exploration allows the UE to gather necessary information (Qoffset values) to make an informed reselection decision, avoiding the need for double reselection and reducing signaling overhead.
Solution Approach 2:
The second cell acts as an intermediary during the cell reselection process. The UE temporarily camps on the second cell to obtain its cell reselection parameters (Qoffset values) without completing the full reselection process. This intermediary step provides the information needed to make accurate reselection decisions and avoid unnecessary signaling.
2Measurement precision
If the UE obtains cell reselection parameters from system information before reselection, then the UE can make accurate reselection decisions, but the UE increases signaling messages and processing time
Solution Approach 1:
The UE performs partial cell reselection by camping on the second cell without completing the full reselection procedure. Instead of obtaining all parameters beforehand, the UE obtains only the necessary cell reselection parameters (Qoffset values) from the second cell's system information, reducing the time and signaling overhead while maintaining sufficient accuracy for the reselection decision.
3Loss of information
If the UE camps on an intermediate cell during reselection, then the UE can obtain cell parameters, but the UE causes uplink interference by transmitting before updating rankings
Solution Approach 1:
The UE dynamically adjusts its transmission behavior based on the cell reselection state. The UE suspends uplink transmissions while camped on the second cell during the parameter collection phase, and only resumes transmissions after updating the cell rankings based on obtained parameters. This dynamic control eliminates uplink interference caused by premature transmissions.
Data Source
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AI summary
Techniques for performing cell reselection in a wireless communication system are described. A user equipment (UE) may initially camp on a first cell. While camped on the first cell, the UE may identify second and third cells deemed to be better than the first cell. The UE may move from the first cell to the second cell without performing cell reselection to camp on the second cell. After moving to the second cell, the UE may obtain at least one cell reselection parameter for the second and/or third cell and may update the rankings of the second and third cells based on the cell reselection parameter(s). The UE may then perform cell reselection from the first cell to the second or third cell based on the updated rankings, e.g., perform inter-frequency cell reselection from the first cell to the third cell without actually camping on the second cell.