Sidelink DRX With Direct Frame Numbers for UE Synchronization

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Solution Overview

Problem

In sidelink communication between UEs, relying on system frame number (SFN) timing for discontinuous reception (DRX) can result in non-overlapping ON durations of DRX cycles, causing difficulty in performing communication due to differing SFN timings among UEs.

Innovation Solution

Configuring sidelink DRX mode using direct frame number (DFN) timing-based DRX parameters to synchronize ON durations across UEs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If SFN timing is used for DRX configuration in sidelink communication, then communication between UEs connected to the same base station can be synchronized, but UEs with different SFN timings will have non-overlapping ON durations, causing communication failure

Engineering Contradiction:

Improvecommunication reliabilityVSAvoidadaptability to different SFN timings

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent changes the timing reference parameter from SFN to DFN. By introducing DFN (Direct Frame Number) as a new timing reference that is specific to sidelink communication, the system enables UEs to synchronize their DRX cycles based on a common DFN timing rather than their individual SFN timings. This parameter change resolves the contradiction by making the timing reference independent of the base station connection status and SFN configurations.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If each UE uses its own SFN timing for DRX cycles, then each UE can independently configure its DRX parameters, but the ON durations of different UEs will not overlap, making sidelink communication difficult

Engineering Contradiction:

Improveindependent DRX configurationVSAvoidsidelink communication efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent introduces DFN as an intermediary timing reference that mediates between individual UE SFN timings and the need for synchronized sidelink communication. Instead of UEs directly using their own SFN timings (which causes non-overlapping ON durations), the DFN serves as a common reference point that all UEs can use to configure their DRX cycles, ensuring that ON durations overlap while still allowing independent configuration of DRX parameters.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Extent of automation

If SFN timing is used for DRX mode, then uplink and downlink signaling can be controlled by base station timing, but sidelink communication between UEs cannot be properly synchronized due to different SFN timings

Engineering Contradiction:

Improvebase station controlled timingVSAvoidsidelink communication reliability

Core Design Contradiction:

Extent of automationVSReliability

Solution Approach 1:

The patent segments the timing control into two independent domains: uplink/downlink communication continues to use SFN timing controlled by the base station, while sidelink communication uses DFN timing independent of the base station. This segmentation allows each communication type to have its own optimized timing reference, resolving the contradiction between base station control and sidelink synchronization reliability.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS12445960B2Discontinuous reception in sidelink communication based on a direct frame number

Publication Date: 2025.10.14 QUALCOMM INC

AI summary

An effective approach for a user equipment (UE) to perform a sidelink communication with another UE in a discontinuous reception (DRX) mode is disclosed. For example, a UE may determine a direct frame number (DFN) timing, and configure a sidelink DRX mode using one or more sidelink DRX parameters based on the DFN timing. The UE may perform a sidelink communication with a second UE during an on-duration of a sidelink DRX cycle in the sidelink DRX mode according to the one or more sidelink DRX parameters.