Sidelink DRX Timer Coordination for Faster HARQ Retransmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In LTE and NR systems, the existing discontinuous reception (DRX) mechanism causes delays in sidelink data retransmission due to the UE entering a sleep mode when a base station schedules sidelink data retransmission, leading to inefficiencies in resource allocation and increased power consumption.
Innovation Solution
Implementing a method that includes configuring two timers, drx-HARQ-RTT-TimerSL and drx-RetransmissionTimerSL, for each sidelink HARQ process to keep the UE in an active mode for monitoring PDCCH scheduling retransmissions, thereby avoiding delays and improving retransmission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the UE enters sleep mode according to the existing DRX mechanism, then power consumption is reduced, but sidelink data retransmission delay increases
Solution Approach 1:
The patent segments the DRX operation into two independent timer mechanisms: drx-HARQ-RTT-TimerSL for managing the round-trip time period and drx-RetransmissionTimerSL for managing the retransmission monitoring period. This segmentation allows the UE to selectively monitor PDCCH only when retransmission is needed, rather than continuously monitoring or completely sleeping, thus resolving the contradiction between power saving and timely retransmission detection
Solution Approach 2:
The patent implements preliminary action by configuring the drx-HARQ-RTT-TimerSL to expire before the drx-RetransmissionTimerSL starts. This ensures that the UE is already in active state and monitoring PDCCH before the actual retransmission occurs, eliminating the delay that would occur if the UE had to wake up from sleep mode after missing the retransmission scheduling
2Loss of time
If the UE continuously monitors the PDCCH, then retransmission timing is maintained, but power consumption increases
Solution Approach 1:
The patent implements periodic action through the DRX cycle structure with configured timers that periodically activate the UE to monitor PDCCH. Instead of continuous monitoring, the UE follows a periodic pattern defined by drx-HARQ-RTT-TimerSL and drx-RetransmissionTimerSL, activating only when these timers indicate potential retransmission events, thus reducing overall power consumption while maintaining timely retransmission response
Solution Approach 2:
The patent changes the operational parameters of the UE by introducing specific timer values (drx-HARQ-RTT-TimerSL and drx-RetransmissionTimerSL) that dynamically control the monitoring behavior. These parameter changes allow the system to adapt between continuous monitoring and sleep modes based on actual retransmission needs, optimizing the balance between power consumption and response timing
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
This application relates to a discontinuous reception method. In the first time unit, for example, the first symbol, after a hybrid automatic repeat request HARQ feedback occasion of a sidelink HARQ process, a first terminal may start a drx-HARQ-RTT-TimerSL and start a drx-RetransmissionTimerSL when the drx-HARQ-RTT-TimerSL expires. During running of the drx-RetransmissionTimerSL, the first terminal monitors a physical downlink control channel. In this way, sidelink retransmission efficiency can be improved, an increase of a sidelink retransmission delay can be avoided, and side link-based applications, such as unmanned driving, automatic driving, assisted driving, intelligent driving, networked driving, intelligent networked driving, and car sharing in the field of artificial intelligence can be better supported.