Sidelink Scheduling Request Cancellation for Low-Latency NR Transmission

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The existing SR cancellation mechanisms in NR systems increase transmission latency for sidelink data, failing to meet service requirements due to inefficient handling of pending scheduling requests.

Innovation Solution

A method for independently canceling pending SRs based on specific conditions, ensuring that sidelink data with high latency requirements are promptly allocated resources by maintaining certain SRs active until necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the existing SR cancellation mechanism is used for sidelink data, then pending SRs are canceled when MAC PDU includes sidelink BSR MAC CE, but transmission latency of sidelink data increases

Engineering Contradiction:

ImproveSR cancellation reliabilityVSAvoidtransmission latency

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent segments the SR cancellation mechanism by type: uplink SRs are canceled when uplink BSR is included in MAC PDU, while sidelink SRs are canceled only when sidelink BSR is included and specific timing conditions are met. This segmentation prevents premature cancellation of sidelink SRs, ensuring low latency transmission while maintaining reliable SR handling.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent applies preliminary action by maintaining sidelink SRs in pending state until specific conditions are satisfied (sidelink BSR inclusion + timing requirements). This prevents premature cancellation and ensures that sidelink data receives timely resource allocation, reducing transmission latency while ensuring reliable SR processing.

Inventive Principle:

Principle #10Preliminary action

2Loss of energy

If all pending SRs are canceled when UL grant can accommodate all available pending data, then resource waste is reduced, but sidelink data transmission latency increases

Engineering Contradiction:

Improveresource wasteVSAvoidtransmission latency

Core Design Contradiction:

Loss of energyVSLoss of time

Solution Approach 1:

The patent applies local quality by differentiating cancellation behavior based on SR type and data characteristics. Uplink SRs follow standard cancellation rules, while sidelink SRs have specialized handling that considers their real-time transmission requirements. This localized differentiation ensures that sidelink SRs are not prematurely canceled, maintaining low latency while reducing unnecessary resource waste from redundant SR transmissions.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP3952426B1Method and device for canceling scheduling requests to be processed

Publication Date: 2025.11.26 HUAWEI TECH CO LTD

Figure 1~2
Figure 3~4
Figure 5~7

AI summary

This application provides a pending SR cancellation method and an apparatus. In the method, when a specific condition is met, a terminal cancels a pending SR triggered by an uplink BSR, and when some other conditions are met, the terminal cancels a pending SR triggered by a sidelink BSR. In other words, the terminal may independently cancel the SR triggered by the uplink BSR and the SR triggered by the sidelink BSR. When canceling the SR triggered by the uplink BSR, the terminal may not cancel the SR triggered by the sidelink BSR, so that when sidelink data has a relatively high latency requirement, the terminal sends a sidelink RS to a network device by using an SR resource dedicated to sending an SL SR (a logical channel associated with the SR resource has a relatively high latency requirement), to request the network device to immediately allocate a transmission resource to the sidelink data, so as to ensure that a low-latency transmission requirement of the sidelink data is met.