Single Radio UE CDRX Timer Management for Multi-RAT Tune-Away
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Solution Overview
Problem
Wireless communication devices supporting multiple radio access technologies (RATs) face performance degradation and increased power consumption due to tune-away operations between different RATs, such as transitioning from LTE to legacy networks like GSM for voice calls, which disrupts LTE performance and increases power usage.
Innovation Solution
Implementing a User Equipment (UE) device with a single radio configured to operate in connected discontinuous reception (CDRX) mode, where timers for the first RAT continue to run even when the radio is used for a second RAT, and page decoding conflicts are managed to avoid unnecessary transitions, allowing the UE to perform CDRX in the first RAT while communicating using the second RAT.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the UE uses a single radio to support multiple RATs and performs tune-away operations from LTE to legacy RATs for voice calls, then the UE can maintain multi-RAT connectivity and support voice services, but LTE performance degrades and power consumption increases
Solution Approach 1:
The patent applies preliminary action by determining whether CDRX timers should continue running before actually tuning away to legacy RAT. The UE evaluates the timing of CDRX on-duration and inactivity timers against the expected duration of tune-away operations, and proactively decides to maintain timer operation to prevent performance degradation. This advance planning allows the UE to preserve LTE synchronization and performance characteristics while still supporting necessary tune-away operations for multi-RAT connectivity.
2Adaptability or versatility
If the UE uses a single radio to support multiple RATs and performs tune-away operations from LTE to legacy RATs, then the UE can maintain multi-RAT connectivity, but power consumption increases
Solution Approach 1:
The patent applies preliminary action by evaluating timer operation decisions before tune-away operations occur. The UE determines in advance whether CDRX timers should continue running based on the timing relationship between CDRX cycles and legacy RAT page occasions, preventing unnecessary timer interruptions that would increase power consumption. This proactive approach minimizes power usage while maintaining multi-RAT connectivity capabilities.
3Use of energy by stationary object
If the UE operates in CDRX mode on the first RAT while the radio is used for the second RAT, then the UE can maintain LTE connectivity and power savings, but timer operation may be disrupted causing performance degradation
Solution Approach 1:
The patent applies preliminary action by determining whether CDRX timers should continue running before tune-away operations to legacy RAT. The UE evaluates the timing of CDRX on-duration and inactivity timers against the expected duration of tune-away operations, and proactively decides to maintain timer operation to prevent disruption. This advance planning allows the UE to preserve CDRX functionality and power savings while still supporting necessary tune-away operations.
Solution Approach 2:
The patent applies copying by maintaining the CDRX timer state and configuration information during tune-away operations. The UE preserves the timer values and CDRX cycle parameters in memory, allowing rapid restoration of normal CDRX operation after returning from legacy RAT. This copying approach ensures that CDRX operation continuity is maintained even when the radio is temporarily used for other RATs.
4Reliability
If the UE continuously monitors the first RAT to maintain performance, then LTE performance is maintained, but power consumption increases
Solution Approach 1:
The patent applies periodic action by implementing CDRX (Connected Discontinuous Reception) mode, where the UE monitors LTE signals periodically rather than continuously. The UE wakes up at scheduled CDRX on-duration intervals to check for LTE activity, then enters sleep mode during inactivity periods. This periodic monitoring approach significantly reduces power consumption compared to continuous monitoring, while the patent ensures that tune-away operations do not disrupt the periodic CDRX cycle by maintaining timer operation.
Data Source
AI summary
Operating a UE device having a single radio configured to communicate using a first and second RAT. The UE may begin operating in a connected discontinuous reception (CDRX) mode of the first RAT, where the CDRX mode comprises an on duration timer and an inactivity timer. The method may determine that the single radio of the UE is being used for a second RAT during the CDRX mode. The UE may operate at least one of a CDRX on duration timer or an inactivity timer of the first RAT while the single radio of the UE is being used for the second RAT. While the single radio of the UE is being used for the second RAT, the at least one of the CDRX on duration timer or the inactivity timer may operate even though no communication or monitoring is performed on the first RAT.