UE PLMN Search During Access Barred State
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Solution Overview
Problem
User equipment (UE) in an access barred state cannot perform a Public Land Mobile Network (PLMN) search, leading to poor user experience due to inability to select and access new PLMNs even when better services are available, as it only performs cell searches within the current PLMN.
Innovation Solution
The UE determines its access barred state and inability to register with the current PLMN, then performs a PLMN search by checking if the current PLMN is a normal PLMN, and if not, initiates a PLMN search using a shorter search period that gradually increases, allowing it to switch to a new PLMN for access and normal service.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE performs only cell search in current PLMN when in access barred state, then the UE maintains access control compliance, but the UE cannot select new PLMN even when better services are available
Solution Approach 1:
The patent segments the network search process into two distinct modes: cell search (for current PLMN) and PLMN search (for new PLMN). When access barred state is detected, the UE activates PLMN search as a separate parallel process, allowing it to find alternative networks while maintaining compliance with access control restrictions on the current network.
Solution Approach 2:
The patent implements dynamic state transition where the UE monitors access barred status and automatically switches between cell search only mode and combined cell search plus PLMN search mode. This dynamic adaptation allows the UE to respond to changing network conditions and access control states in real-time.
2Adaptability or versatility
If the UE performs PLMN search when in access barred state, then the UE can find and access new PLMN for better services, but the UE increases search time and energy consumption
Solution Approach 1:
The patent performs preliminary detection of access barred state through monitoring system information blocks (SIBs) and access control parameters before initiating full PLMN search. This preliminary action allows the UE to prepare for potential PLMN search by pre-identifying access restrictions, enabling faster response when PLMN search becomes necessary.
Solution Approach 2:
The patent implements periodic monitoring of access barred status and periodic PLMN search at defined intervals when in access barred state. This periodic approach balances the need to find alternative networks with the need to conserve energy and minimize search time, searching at regular intervals rather than continuously.
3Speed
If the UE performs PLMN search with shorter search period, then the UE quickly finds new PLMN, but the UE increases energy consumption and processing load
Solution Approach 1:
The patent dynamically changes the PLMN search period parameter based on the UE's access barred state. When access barred state is detected, the UE switches to a shorter search period to quickly find alternative networks. When normal service is available, the UE uses a longer search period to conserve energy. This parameter adjustment optimizes the balance between search speed and energy consumption.
Data Source
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AI summary
The present invention discloses a method and an apparatus for searching for a network. The method includes: determining that a user equipment UE camping on a cell of a current public land mobile network PLMN is in an access barred state; determining that the UE cannot be successfully registered with the current PLMN; and performing a PLMN search. In the method and the apparatus for searching for a network according to embodiments of the present invention, if it is determined that the UE normally camping on the cell of the current PLMN is in the access barred state and cannot be successfully registered with the current PLMN, the PLMN search is performed, so that when the UE is in the access barred state, the UE can still perform the PLMN search, and can further select a new PLMN for access and execute a normal service, thereby improving user experience.