Aperiodic Scheduling Request in 5G NR Uplink Control
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Solution Overview
Problem
In 5G New Radio systems, existing mechanisms for transmitting scheduling requests from User Entities (UE) to the network face challenges, particularly when multiple UEs have overlapping periodic scheduling request opportunities, leading to decoding issues and inefficient resource utilization.
Innovation Solution
The proposed solution involves a method where the User Entity (UE) determines whether an SR-PUCCH is present in a slot. If not, it generates a scheduling request (SR) and appends it to the HARQ-ACK information, transmitting both together on the HARQ-ACK PUCCH, thereby eliminating the need for separate SR-PUCCH transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate SR-PUCCH transmissions are used for scheduling requests, then scheduling requests can be transmitted reliably, but resource utilization becomes inefficient and decoding complexity increases when multiple UEs have overlapping periodic opportunities
Solution Approach 1:
The patent merges the scheduling request (SR) transmission with the HARQ-ACK PUCCH transmission by appending the SR bit to the HARQ-ACK message. This combining approach allows both SR and HARQ-ACK to be transmitted in a single PUCCH resource, eliminating the need for separate SR-PUCCH transmissions and reducing resource waste when multiple UEs have overlapping periodic SR opportunities.
Solution Approach 2:
The HARQ-ACK PUCCH is designed to serve multiple functions simultaneously: it carries both HARQ-ACK feedback bits and scheduling request (SR) information bits. This multi-functionality allows the same PUCCH resource to handle both uplink data acknowledgments and scheduling requests, improving resource utilization efficiency while maintaining reliable transmission of both types of information.
2Ease of operation
If separate SR-PUCCH transmissions are used for scheduling requests, then scheduling requests can be transmitted independently, but device complexity and decoding complexity increase
Solution Approach 1:
The patent combines SR and HARQ-ACK transmissions into a single PUCCH message, reducing the number of separate decoding operations required at the gNB. Instead of separately decoding SR-PUCCH and HARQ-ACK PUCCH, the network decodes a single combined message, thereby reducing decoding complexity while still maintaining the ability to independently process scheduling request information.
3Reliability
If periodic SR opportunities are configured for multiple UEs, then each UE can transmit scheduling requests regularly, but overlapping transmissions lead to resource waste and inefficiency
Solution Approach 1:
The HARQ-ACK PUCCH resource is designed to universally handle both HARQ-ACK feedback and scheduling request transmissions. When multiple UEs have periodic SR opportunities that would otherwise overlap and waste resources, they can all utilize the same HARQ-ACK PUCCH resource to transmit their SR bits appended to their respective HARQ-ACK messages, thereby eliminating resource waste while maintaining reliable periodic scheduling request transmission.
Data Source
AI summary
Method for a User Entity, UE, being adapted to transmit uplink data according to a NR TDD scheme, with a NR bases station, gNB, the UE being further adapted to transmit HARQ-ACK information, being an ACK or a NACK for received data on a downlink channel and a Scheduling Request, SR, may be provided comprising an indication of data or no data to be pending for transmittal on the up-link. The method comprises-establishing if HARQ-ACK info is available in a slot (203), —establishing if an SR-PUCCH is present in the slot (204), —if no SR-PUCCH present in the slot, generating (208) a SR, —appending (209) the SR to the HARQ-ACK, —transmitting (211) the SR appended to the HARQ-ACK.