Frequency Value Modification for Efficient PLMN Search
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Solution Overview
Problem
UMTS user equipment (UE) faces significant time consumption and resource usage in searching for available PLMNs across multiple frequencies, as existing methods are limited in storing frequencies that do not align with the 200 kHz raster, leading to inefficient cell reselection processes.
Innovation Solution
The method involves storing additional frequencies by shifting them onto the 200 kHz raster using an arithmetical operation, allowing these frequencies to be stored and retrieved efficiently within the EF NETPAR file, enabling UE to associate the frequency with a specific band and reducing the time required for cell reselection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the UE stores all frequencies including those not on the 200 kHz raster, then the completeness of frequency information is improved, but the compatibility with existing storage structures deteriorates
Solution Approach 1:
The patent applies parameter changes by modifying the frequency value through an arithmetical operation (subtracting an offset) to transform it into a compatible form for storage. The original frequency parameter is altered by a fixed amount to map it onto the 200 kHz raster, enabling storage in existing structures while preserving the ability to retrieve and use the frequency information.
2Reliability
If the UE performs a full PLMN search across all frequencies, then the reliability of PLMN detection is improved, but the time consumption deteriorates
Solution Approach 1:
The patent applies preliminary action by storing frequency information from previously used cells in advance. When the UE needs to perform PLMN detection, it can first check the stored frequency information and prioritize searching on these frequencies, rather than performing a complete search across all possible frequencies from scratch. This preliminary preparation significantly reduces the time required while maintaining detection reliability.
3Speed
If the UE prioritizes searching on previously used frequencies, then the speed of PLMN detection is improved, but the risk of missing available PLMNs on other frequencies increases
Solution Approach 1:
The patent applies partial action by performing PLMN detection on a subset of frequencies (those in the stored information) rather than all possible frequencies. The UE performs detection on the stored frequencies first, and if needed, can extend the search to other frequencies. This partial approach achieves faster detection speed for common cases while maintaining the option to ensure completeness when necessary.
Data Source
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AI summary
A method, in a wireless communications apparatus, the method comprising: identifying a previously used frequency as incompatible with a parameter storage area; performing an arithmetical operation on the value of the previously used frequency to give a modified value of the previously used frequency; and storing the modified value of the previously used frequency in the parameter storage area.