SL Buffer Status Reporting via LCG Mapping in U2U Relay

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Solution Overview

Problem

In U2U relay scenarios, relay UEs cannot obtain direct communication interface resources for data forwarding due to the lack of QoS profile mapping, preventing effective SL BSR reporting.

Innovation Solution

The relay terminal acquires a mapping between a first target object and a second hop LCG ID, sending an SL BSR to the network device, utilizing configuration information and assistance information through PC5-RRC signaling, MAC CE, or SCI to determine LCG IDs for resource allocation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If the relay terminal uses traditional QoS profile reporting process, then the terminal can obtain the mapping relationship between QoS identifier and LCG, but the relay terminal cannot learn the QoS profile corresponding to the data to be sent

Engineering Contradiction:

ImproveQoS profile mapping informationVSAvoidapplicability to U2U relay scenario

Core Design Contradiction:

Loss of informationVSAdaptability or versatility

Solution Approach 1:

The patent introduces a mapping relationship between first target objects (first hop SL RLC channel, second hop SL RLC channel, or end-to-end bearer) and second hop LCG ID as an intermediary mechanism. This allows the relay terminal to report buffer status without needing to learn the QoS profile directly, solving the information loss problem in U2U relay scenarios where traditional QoS profile reporting is not applicable.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If the relay terminal cannot obtain LCG corresponding to data through QoS profile reporting, then the relay terminal cannot perform SL BSR reporting, but this prevents the relay terminal from obtaining direct communication interface resources

Engineering Contradiction:

ImproveSL BSR reporting capabilityVSAvoiddata forwarding efficiency

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The patent changes the reporting parameters from QoS profile-based LCG mapping to a direct mapping between first target objects and second hop LCG ID. This parameter change enables the relay terminal to perform SL BSR reporting by reporting the mapping relationship and buffer status, thereby obtaining direct communication interface resources for data forwarding and improving productivity.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4712657A1Method and apparatus for reporting buffer area status report, and terminal and network device

Publication Date: 2026.03.18 DATANG MOBILE COMM EQUIP CO LTD

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AI summary

The present disclosure provides a buffer status reporting method, apparatus, terminal, and network device. The method comprises: a relay terminal acquiring a mapping between a first target object and a second hop LCG ID; and sending an SL BSR to a first network device according to the mapping between the first target object and the second hop LCG ID; wherein the first target object comprises one of the following: a first hop SL RLC channel; a second hop SL RLC channel; an end-to-end bearer between a first terminal and a second terminal.