Background PLMN Search in Multi-RAT Wireless Terminals
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Solution Overview
Problem
Existing wireless terminals face inefficiencies in performing background Public Land Mobile Network (PLMN) searches across multiple Radio Access Technologies (RATs, leading to prolonged service from a Visited PLMN even when a nearby Home PLMN base station exists, due to inadequate scanning times and inefficient RAT switching.
Innovation Solution
A method and apparatus that calculate a sleep interval for background PLMN searching, determining whether to perform the search in a passive or active RAT based on the interval's length relative to a reference parameter, ensuring efficient PLMN searching by prioritizing passive RAT searches when sufficient time is available and switching to active RAT if the interval is too short.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the wireless terminal performs background PLMN searching by switching between multiple RATs, then the search coverage is improved, but the time required for searching increases and scanning efficiency deteriorates
Solution Approach 1:
The patent applies preliminary action by performing measurements on passive RATs during idle periods before they are needed for PLMN searching. The terminal measures and stores frequency information of passive RATs in advance, so when PLMN searching is required, the terminal can quickly switch to the target RAT without performing measurements during the critical search window, thus reducing overall searching time while maintaining multi-RAT search coverage
Solution Approach 2:
The patent implements dynamics by adaptively adjusting the measurement timing and resource allocation based on the terminal's operational state. The terminal dynamically schedules measurements of passive RATs during idle periods when no active communication is occurring, and dynamically selects which RATs to measure based on configuration information and current network conditions, optimizing the balance between search coverage and time consumption
2Reliability
If the wireless terminal performs comprehensive PLMN searching across all RATs, then the reliability of network selection is improved, but the complexity of the searching procedure increases
Solution Approach 1:
The patent applies segmentation by dividing the PLMN searching procedure into distinct phases: active RAT searching during active communication periods and passive RAT searching during idle periods. The terminal segments the measurement tasks by separating active RATs (currently used for communication) from passive RATs (not currently used), and handles their measurements at different times, thereby reducing the complexity of simultaneous multi-RAT searching while maintaining comprehensive search coverage
Solution Approach 2:
The patent implements periodic action by scheduling measurements of passive RATs during periodic idle intervals between active communication sessions. The terminal utilizes the periodic nature of idle periods to systematically measure passive RATs, ensuring that all RATs are searched comprehensively over time without requiring complex simultaneous coordination of multiple RAT measurements
3Adaptability or versatility
If the wireless terminal switches between active and passive RATs for searching, then the scanning flexibility is improved, but the energy consumption increases
Solution Approach 1:
The patent applies preliminary action by performing measurements on passive RATs during idle periods when the terminal is not actively communicating. By measuring and storing frequency information of passive RATs in advance during these low-power idle states, the terminal avoids the need to wake up and consume additional energy specifically for measurements during active communication periods, thus reducing overall energy consumption while maintaining scanning flexibility
Solution Approach 2:
The patent implements periodic action by scheduling RAT measurements during periodic idle intervals rather than continuously. The terminal exploits the periodic occurrence of idle periods to systematically measure passive RATs, ensuring comprehensive coverage over time while minimizing energy consumption by concentrating measurements during naturally occurring low-power states rather than maintaining continuous measurement operations
Data Source
AI summary
A method and apparatus of searching for an operator network in a multi-Radio Access Technology (RAT) environment are provided. The method, calculating a length of a sleep interval to perform background Public Land Mobile Network (PLMN) searching, comparing the length of the sleep interval with a predetermined reference parameter, if the length of the sleep interval is larger than the reference parameter, performing background PLMN searching of a passive RAT during the sleep interval, and if the length of the sleep interval is equal to or smaller than the reference parameter, performing background PLMN searching of an active RAT during the sleep interval.