Sidelink DRX HARQ Timing for Unlicensed Communication Reliability
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Solution Overview
Problem
The increasing demand for mobile broadband communication and V2X services necessitates improved sidelink communication methods to handle larger data capacities and reduce latency, especially in unlicensed bands, while ensuring reliability and efficiency in wireless communication systems.
Innovation Solution
The implementation of sidelink (SL) discontinuous reception (DRX) configuration, including a hybrid automatic repeat request (HARQ) round trip time (RTT) timer, to manage the transmission and reception of sidelink control information (SCI) and physical sidelink shared channels (PSSCH), with pending physical sidelink feedback channel (PSFCH) information, to optimize resource utilization and latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sidelink communication is performed in unlicensed band without DRX configuration, then resource utilization is improved, but power consumption increases and latency is not optimized
Solution Approach 1:
The patent implements DRX (Discontinuous Reception) configuration that periodically switches the UE between active and sleep states. The SL DRX cycle, onDurationTimer, and HARQ RTT timer create periodic monitoring intervals, allowing the UE to conserve power by sleeping between periods while still maintaining sidelink communication capability in unlicensed band.
Solution Approach 2:
The patent configures DRX parameters in advance before sidelink communication begins. The network or UE pre-configures the SL DRX cycle, onDurationTimer values, and HARQ RTT timer settings, so that the UE can immediately enter optimized power-saving mode without dynamic adjustments during communication.
2Use of energy by moving object
If DRX configuration is applied to sidelink communication, then power consumption is reduced, but communication latency may increase
Solution Approach 1:
The patent dynamically adjusts DRX parameters based on communication conditions. The SL DRX onDurationTimer can be extended or shortened, and the HARQ RTT timer can be adjusted to match actual traffic patterns, allowing the system to optimize between power saving and latency reduction in real-time based on whether traffic is active or dormant.
Solution Approach 2:
The patent pre-configures multiple DRX parameter sets and selects appropriate configurations based on QoS requirements. For latency-sensitive services, shorter onDurationTimer values are pre-configured, while for power-sensitive applications, longer sleep intervals are pre-configured, allowing rapid adaptation without real-time optimization complexity.
3Reliability
If SL DRX HARQ RTT timer is started after PSFCH resource, then HARQ feedback reliability is improved, but timing synchronization complexity increases
Solution Approach 1:
The patent segments the HARQ feedback process into distinct phases: PSFCH resource allocation phase and HARQ RTT timer phase. By separating these functions and assigning them to different time intervals, the system ensures that HARQ feedback is reliably received before retransmission timing begins, improving reliability while managing complexity through functional separation.
Solution Approach 2:
The patent performs PSFCH feedback transmission before starting the SL DRX HARQ RTT timer. This preliminary action ensures that HARQ acknowledgment is exchanged and confirmed before the UE enters DRX sleep mode or schedules retransmission, guaranteeing feedback reliability while the timer configuration manages the timing complexity.
Data Source
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AI summary
Provided are a method performed by a first device in a wireless communication system, and an apparatus supporting same. The method may comprise the steps of: acquiring sidelink (SL) discontinuous reception (DRX) configuration information including information related to an SL DRX hybrid automatic repeat and request (HARQ) round time trip (RTT) timer; receiving, via a first physical sidelink control channel (PSCCH), first SCI for scheduling second sidelink control information (SCI) and a first physical sidelink shared channel (PSSCH); and receiving the second SCI via the first PSSCH. For example, at least one of the first SCI and the second SCI may include information for physical sidelink feedback channel (PSFCH) pending. For example, on the basis of the information for the PSFCH pending, a first PSFCH transmission may be pending in a first PSFCH resource related to the first PSSCH. For example, the SL DRX HARQ RTT timer may start after the first PSFCH resource.