PSFCH Negotiation for Priority-Based Sidelink Feedback

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Solution Overview

Problem

Receiving UEs in wireless communication networks are limited in their ability to concurrently transmit physical sidelink feedback channel (PSFCH) signals, leading to incomplete feedback for sidelink sessions and potential disruptions when new UEs join, affecting existing connections.

Innovation Solution

UEs negotiate PSFCH signaling capabilities by determining and agreeing on conditions such as maximum PSFCH transmissions, priority rules, and power allocations during sidelink connection establishment, allowing for efficient resource management and renegotiation based on session priorities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a receiving UE transmits PSFCH signals to all sidelink sessions concurrently, then complete feedback is provided for all sessions, but the UE exceeds its transmission capability limits

Engineering Contradiction:
Improvefeedback completenessVSAvoidtransmission capability
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic PSFCH transmission by allowing the receiving UE to adaptively select which sessions receive feedback based on current conditions. The UE dynamically adjusts feedback transmission decisions according to its current transmission load, session priorities, and capability limits, rather than attempting to provide feedback to all sessions simultaneously. This resolves the contradiction by making the feedback system flexible and adaptive to the UE's actual transmission capabilities.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of feedback transmission by introducing priority-based filtering and selective feedback mechanisms. The receiving UE evaluates sessions based on priority levels and selectively transmits PSFCH signals only to high-priority sessions when capacity is limited. This parameter change in feedback transmission behavior allows the system to operate within UE capability limits while maintaining reliability for critical communications.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If a receiving UE limits the number of concurrent PSFCH transmissions, then transmission capability constraints are satisfied, but feedback is incomplete for some sessions

Engineering Contradiction:
Improvetransmission capabilityVSAvoidfeedback completeness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by differentiating feedback transmission quality across different sessions. Instead of uniform feedback to all sessions, the receiving UE provides high-priority feedback to selected sessions while omitting or reducing feedback to lower-priority sessions. This local differentiation in feedback quality allows the UE to satisfy its transmission capability constraints while ensuring that critical sessions receive complete and reliable feedback.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements partial action by providing feedback to only a subset of sessions rather than all sessions. The receiving UE selectively provides feedback to high-priority sessions when capacity is limited, accepting that some sessions will not receive feedback in certain time periods. This partial feedback approach allows the system to operate within transmission capability limits while maintaining overall system reliability through priority-based selection.

Inventive Principle:
Principle #16Partial or excessive action

3Adaptability or versatility

If a receiving UE modifies feedback transmission rules when a new UE joins, then new sidelink connections are accommodated, but existing connections are disrupted

Engineering Contradiction:
Improveconnection acceptanceVSAvoidexisting connection stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by having UEs negotiate and agree upon feedback transmission rules during the initial sidelink connection establishment. The receiving UE and transmitting UE exchange capability information and establish feedback transmission agreements before actual data transmission begins. This preliminary negotiation ensures that when new UEs join, the pre-established rules provide a stable foundation, and modifications can be made through controlled renegotiation rather than abrupt changes, thus maintaining connection stability while allowing adaptability.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent implements feedback mechanisms where UEs monitor the performance and stability of existing connections. When a new UE joins and feedback transmission rules need modification, the system uses feedback from existing connections to determine whether changes are necessary and how to implement them minimally. This feedback-driven approach allows the system to adapt to new connections while preserving the stability of existing connections by making only necessary, controlled modifications.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP4039052B1Physical sidelink feedback channel, psfch, negotiation
Publication Date: 2025.11.19 QUALCOMM INC
  • EP4039052B1 patent drawingFigure 1
  • EP4039052B1 patent drawingFigure 2
  • EP4039052B1 patent drawingFigure 3

AI summary

Wireless communications systems and methods related to mechanisms to provide physical sidelink feedback channel (PSFCH) negotiation during sidelink connection establishment. A first UE may determine one or more conditions for PSFCH communications via the sidelink session(s) with the second UE. If the second UE accepts the conditions provided, the first and second UEs complete the sidelink connection. Further, while the first UE has a sidelink communication session with the second UE, a third UE may initiate another sidelink connection with the first UE. The first UE may compare the priority of the proposed sidelink connection with the priority of the ongoing sidelink communication session with the second UE. If the second UE's priority is greater, the first UE will maintain second UE's status. If less, the first UE may engage in a renegotiation with second UE for the ongoing sidelink communication session to update their PSFCH conditions.