Frequency Deprioritization Handling in Wireless UE
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Solution Overview
Problem
In wireless communication systems, when a user equipment (UE) receives a deprioritization request from one public land mobile network (PLMN), it incorrectly de-prioritizes frequencies used by another PLMN, leading to inefficient cell reselection and service disruptions, as the UE cannot follow the new PLMN's configuration until the deprioritization timer expires.
Innovation Solution
A method where the UE only considers a carrier frequency indicated in a deprioritization request as the lowest priority when selecting or registering to the originating PLMN, allowing it to adjust priorities according to the new PLMN's configuration upon registration, thereby avoiding service disruptions and enabling timely access to services.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE stores deprioritisationReq from a first PLMN until timer expiry, then the UE maintains consistent frequency priority handling for that PLMN, but the UE cannot efficiently follow the configuration of a second PLMN when camping on it
Solution Approach 1:
The invention segments the deprioritisation handling by introducing PLMN-specific storage and timer mechanisms. The UE now maintains separate deprioritisationReq and timer instances for each PLMN, allowing independent management of frequency priorities per network. This enables the UE to apply deprioritisation rules from the first PLMN only when camping on that specific PLMN, while adapting to the second PLMN's configuration without interference.
2Reliability
If the UE applies deprioritisationReq from the first PLMN while camping on the second PLMN, then the UE maintains the original frequency priority policy, but the second PLMN cannot efficiently control the UE performing cell reselection
Solution Approach 1:
The invention applies local quality by making deprioritisation policy application context-dependent on the current PLMN. The UE checks whether the stored deprioritisationReq corresponds to the current PLMN before applying it. This ensures that frequency priority policies are enforced locally and appropriately for each PLMN context, allowing efficient cell reselection controlled by the current PLMN while maintaining reliable policy enforcement for the originating PLMN when relevant.
3Reliability
If the UE considers the current frequency as lowest priority due to stored deprioritisationReq, then the UE follows the first PLMN's frequency priority assignment, but the UE cannot access services on frequencies preferred by the second PLMN
Solution Approach 1:
The invention introduces dynamics by making the deprioritisation policy application conditional and changeable based on PLMN context. The UE dynamically determines whether to apply stored deprioritisationReq based on whether it corresponds to the current PLMN. This dynamic approach allows the UE to switch between following the first PLMN's frequency priority assignment and accessing services on frequencies preferred by the second PLMN, ensuring both compliance and service accessibility.
Data Source
AI summary
A method of handling frequency de-prioritization for a communication device in a wireless communication system is disclosed. The method comprises receiving a first Radio resource control (RRC) connection reject message with a first deprioritization request indicating at least one first carrier frequency to be the lowest priority frequency, from a first public land mobile network (PLMN) of the wireless communication system, and determining the at least one first carrier frequency to be the lowest priority frequency only when the communication device selects or registers to the first PLMN.