Relay WTRU Flow Control in Multipath Sidelink Transmission

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Solution Overview

Problem

Existing technologies for multipath sidelink operations in ProSe UE-to-Network relays do not effectively address the dynamic conditions faced by relay WTRUs, leading to inefficiencies in data transmission and reception.

Innovation Solution

A remote WTRU receives configuration information for data transmission over direct and sidelink channels, and relays data using flow control information based on triggering conditions, while the relay WTRU transmits flow control information to adjust the remote WTRU's transmission behavior.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the remote WTRU transmits data over both direct link (Uu) and sidelink (SL) without flow control, then data transmission volume increases, but transmission efficiency decreases due to lack of optimization based on relay WTRU conditions

Engineering Contradiction:

Improvedata transmission efficiencyVSAvoidflow control mechanism complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The relay WTRU provides flow control information to the remote WTRU based on its buffer status and transmission conditions. This feedback mechanism enables the remote WTRU to adjust its data transmission rate and path selection dynamically, optimizing transmission efficiency while preventing buffer overflow at the relay WTRU.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the distribution percentage of data over Uu and SL links based on real-time flow control information. The remote WTRU can switch between different transmission modes (direct-only, relay-only, or combined) depending on the current network conditions and relay status, making the system adaptable rather than static.

Inventive Principle:

Principle #15Dynamics

2Adaptability or versatility

If the relay WTRU buffers data from multiple remote WTRUs, then network coverage extends to more out-of-coverage UEs, but buffer overflow risk increases leading to data loss

Engineering Contradiction:

Improvenetwork coverage capabilityVSAvoiddata transmission reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The relay WTRU monitors its buffer status and provides flow control information back to remote WTRUs. When the buffer approaches capacity, the relay signals remote WTRUs to reduce transmission rate or switch to direct link, preventing buffer overflow and ensuring reliable data transmission while maintaining extended coverage capability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

Instead of allowing the buffer to fill completely before taking action, the flow control mechanism proactively limits data intake when the buffer reaches a threshold level. This partial action (reducing intake before overflow) prevents data loss while maintaining the ability to serve multiple remote WTRUs.

Inventive Principle:

Principle #16Partial or excessive action

3Adaptability or versatility

If the remote WTRU uses only direct link (Uu) for data transmission, then transmission path simplicity increases, but network coverage is limited to areas with base station access

Engineering Contradiction:

Improvenetwork coverage rangeVSAvoidmultipath transmission complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The remote WTRU is designed to perform multiple transmission functions: direct transmission to base station, relayed transmission through other WTRUs, and dynamic switching between modes. This multi-functionality enables the system to extend coverage to out-of-coverage areas while maintaining the option for simple direct transmission when available.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system dynamically selects between direct link only, sidelink relay, or combined paths based on real-time conditions. When base station coverage is available, simple direct transmission is used; when out-of-coverage, the system automatically routes data through relay WTRUs, making the complexity adaptive rather than constant.

Inventive Principle:

Principle #15Dynamics

4Productivity

If flow control information is transmitted frequently from relay to remote WTRU, then transmission optimization accuracy improves, but signaling overhead increases

Engineering Contradiction:

Improvetransmission optimization accuracyVSAvoidsignaling time overhead

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

Flow control information is transmitted periodically or event-triggered rather than continuously. The relay WTRU sends flow control updates at configured intervals or when specific conditions change (e.g., buffer status threshold crossed), balancing optimization accuracy with reduced signaling overhead compared to continuous feedback.

Inventive Principle:

Principle #19Periodic action

Data Source

PatentUS20260020088A1Methods, architectures, apparatuses and systems for utilizing flow control from a relay WTRU in multipath sidelink operations

Publication Date: 2026.01.15 INTERDIGITAL PATENT HOLDINGS INC

AI summary

Procedures, methods, architectures, apparatuses, systems, devices, and computer program products for utilizing flow control from a relay wireless transmit/receive unit (WTRU) in multipath operation which includes sidelink communication with a remote WTRU. In a representative example, a relay WTRU may provide flow control information to a remote WTRU. The flow control information may be associated with remote WTRU actions. The remote WTRU may perform one or more actions based on the reception of the flow control information from the relay WTRU.