Sidelink Carrier Reselection Under DTX-Based Radio Link Failure
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Solution Overview
Problem
Existing wireless communication systems face challenges in managing sidelink radio link failures due to discontinuous transmissions (DTXs) on candidate SL carriers, leading to inefficient SL carrier selection and potential loss of SL radio resource control connections.
Innovation Solution
A method for wireless devices to trigger a SL carrier selection procedure when a threshold number of DTXs is reached, determining unavailable carriers based on channel busy ratio (CBR), and releasing the SL RRC connection to manage sidelink radio link failures effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a wireless device continues transmitting on a sidelink carrier with high DTX count, then transmission continuity is maintained, but reliability of SL connection deteriorates due to radio link failure
Solution Approach 1:
The patent applies preliminary action by triggering a SL carrier selection procedure before the radio link failure becomes irreversible. When the DTX count reaches a threshold, the device proactively initiates carrier selection to identify alternative carriers, preventing complete connection loss while maintaining transmission continuity through planned carrier switching.
2Reliability
If the wireless device performs carrier selection procedure frequently to avoid DTX-related failures, then SL connection reliability is improved, but device complexity and signaling overhead increase
Solution Approach 1:
The patent applies parameter changes by using the DTX count as a threshold-based parameter to trigger carrier selection. Instead of continuous monitoring or frequent selection, the system changes the carrier only when the DTX parameter reaches a predefined threshold, reducing unnecessary selection procedures while maintaining connection reliability.
3Productivity
If the wireless device releases SL RRC connection when no carriers are available, then resource allocation efficiency is improved, but loss of SL connection occurs
Solution Approach 1:
The patent applies the taking out principle by extracting the problematic carrier from the active SL carrier list when no suitable carriers are available during selection. Instead of maintaining a failed connection, the device removes the unavailable carrier and releases the SL RRC connection, allowing resource allocation to be redirected to other carriers or connections, thus improving overall resource efficiency.
Data Source
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Figure 3
AI summary
A first wireless device receives one or more messages indicating sidelink (SL) carriers associated with an SL radio resource control (RRC) connection to a second wireless device and a discontinuous transmission (DTX) threshold value for an SL carrier selection procedure. The first wireless device may select one or more first SL carriers from the SL carriers. The SL carrier selection procedure for the SL RRC connection may be triggered by one or more DTXs occurring on the one or more first SL carriers of the SL carriers and a number of the one or more DTXs being equal to the DTX threshold value. The first wireless device may select a second SL carrier among the SL carriers during the triggered SL carrier selection procedure. The first wireless device may also transmit a SL transport block via the second SL carrier to the second wireless device.