Scheduling Request Indication for URLLC Latency Reduction
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Solution Overview
Problem
Current wireless communication systems face challenges in achieving ultra-reliable and low-latency communications (URLLC) due to user plane latency issues, particularly in grant-based transmission methods where scheduling requests and data transmission do not facilitate the required 1 ms latency for small data packets.
Innovation Solution
The solution involves apparatuses and methods for scheduling request indication that include transmitting a scheduling request with specific indications such as traffic type, number of transmissions, scheduling interval, and latency requirements, allowing for grant-free transmissions and data transmission in response to uplink grants, enabling efficient URLLC communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grant-based transmission with scheduling request is used, then transmission reliability is improved, but user plane latency increases beyond 1 ms
Solution Approach 1:
The patent segments the transmission process by separating grant-based transmissions from grant-free transmissions. Small data packets (e.g., URLLC traffic) use grant-free transmission to avoid scheduling request delays, while larger packets use grant-based transmission for reliability. This segmentation allows different latency requirements to be met by different transmission modes.
Solution Approach 2:
The system dynamically selects between grant-based and grant-free transmission modes based on traffic characteristics, packet size, and latency requirements. The base station and UE can switch between modes adaptively, making the transmission system flexible enough to meet both reliability and latency requirements for different scenarios.
2Device complexity
If traditional scheduling request procedure is used, then resource allocation control is improved, but transmission speed decreases
Solution Approach 1:
The patent implements preliminary action by pre-configuring grant-free transmission resources and parameters before data arrival. The base station pre-allocates resources and configures UE with transmission parameters in advance, so when small data packets arrive, they can be transmitted immediately without going through the traditional scheduling request procedure, thus improving transmission speed while maintaining resource allocation control.
3Reliability
If multiple transmission steps (SR, UL grant, BSR, data) are used, then transmission reliability is improved, but latency increases
Solution Approach 1:
The patent extracts the essential elements needed for reliable transmission (ACK/NACK feedback, HARQ retransmission) while removing the time-consuming steps (scheduling request, buffer status report) for small data packets. The grant-free transmission maintains reliability through extracted key mechanisms like HARQ while eliminating unnecessary steps that cause latency.
4Loss of time
If grant-free transmission is implemented, then user plane latency is reduced, but resource allocation efficiency may worsen
Solution Approach 1:
The patent applies local quality by allocating different resource types and transmission modes to different traffic types and users. Grant-free resources are allocated specifically for small data packets with strict latency requirements, while grant-based resources serve other traffic. This localized resource allocation ensures high efficiency for URLLC traffic while maintaining overall system resource utilization.
Data Source
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AI summary
Apparatuses, methods, and systems are disclosed for scheduling request indication. One apparatus includes a transmitter that transmits a scheduling request in response to data arriving at a buffer. The scheduling request includes an indication of a traffic type, a requested number of scheduling transmissions, an expected number of transmissions, an expected scheduling interval, a latency requirement, or some combination thereof. The apparatus also includes a receiver that receives an uplink grant in response to transmitting the scheduling request. The transmitter transmits the data in response to receiving the uplink grant.