DRX Retransmission Timer Adjustment for Measurement Gap Collisions
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Solution Overview
Problem
The existing Discontinuous Reception (DRX) mechanism in LTE systems fails to adequately account for collisions between measurement gaps and HARQ retransmissions, leading to missed retransmissions and increased power consumption, especially for real-time services like VoIP.
Innovation Solution
The DRX Retransmission Timer is adjusted by temporarily suspending or extending the retransmission-monitoring interval when a collision with a measurement gap is detected, ensuring the UE monitors the PDCCH for additional retransmission attempts, thereby reducing unnecessary power usage and packet loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DRX Retransmission Timer is configured to a fixed value according to specifications, then the UE can follow standard protocols, but the UE may miss retransmissions when measurement gaps collide with retransmission intervals
Solution Approach 1:
The patent makes the DRX Retransmission Timer dynamic by allowing it to be adjusted based on detected collisions with measurement gaps. When a collision is detected, the timer value is modified to extend the monitoring interval beyond the original fixed specification, enabling the UE to adapt its retransmission monitoring behavior to actual channel conditions and measurement requirements.
Solution Approach 2:
The patent implements a feedback mechanism where the UE monitors for collisions between the DRX Retransmission Timer and measurement gaps, and uses this detection information to adjust the timer value. This closed-loop approach allows the system to respond to actual collision events and improve retransmission reliability based on observed conditions rather than relying solely on fixed pre-configured values.
2Reliability
If the UE extends the DRX Retransmission Timer to cover measurement gaps, then retransmission monitoring reliability improves, but power consumption increases due to extended awake intervals
Solution Approach 1:
The patent dynamically adjusts the DRX Retransmission Timer duration based on actual collision detection rather than using a permanently extended fixed value. The timer is extended only when and where collisions with measurement gaps are detected, allowing the UE to maintain standard power-saving behavior during non-collision periods while ensuring reliable retransmission monitoring only when necessary.
Solution Approach 2:
The patent applies the extension of monitoring intervals locally and selectively - only during time periods where collisions with measurement gaps are detected, rather than extending the monitoring interval globally across all retransmission opportunities. This localized approach ensures reliability only where needed while preserving power savings during normal operation.
3Reliability
If the UE frequently monitors PDCCH for retransmissions, then packet loss decreases, but battery life is reduced due to increased receiver activity
Solution Approach 1:
The patent dynamically adjusts the DRX Retransmission Timer to extend monitoring only when collisions with measurement gaps are detected, rather than maintaining frequent monitoring at all times. This dynamic adjustment ensures packet delivery reliability during collision events while preserving battery life during normal non-collision operation by maintaining standard DRX sleep intervals.
Solution Approach 2:
The patent changes the temporal parameters of PDCCH monitoring by adjusting the DRX Retransmission Timer duration based on collision detection. The monitoring interval is extended only when necessary to capture retransmissions that would otherwise be missed during measurement gaps, optimizing the balance between packet delivery reliability and power consumption.
Data Source
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AI summary
Methods and apparatus for controlling discontinuous receiver operation in a wireless communication device are disclosed. In an exemplary embodiment, a wireless communication device (150) configured to monitor a downlink signal during a series of regularly scheduled awake intervals and monitor the downlink signal for retransmissions during retransmission- monitoring intervals scheduled at a first predetermined delay from each detected data transmission to the receiver includes a control circuit (175) configured to detect that a first retransmission-monitoring interval overlaps a previously scheduled radio activity during which the receiver is unavailable to monitor the first downlink signal, such as a measurement gap, and to adjust the first retransmission-monitoring interval, add an additional retransmission- monitoring interval, or both, responsive to said detecting.