Uplink Auto-Grant Scheduling for Cellular Latency Reduction
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Solution Overview
Problem
Current methods to reduce uplink latency in 4G and 5G radio access networks are inefficient due to unreliable data prediction and wasteful proactive grants, as they often allocate resources to UEs without actual traffic, leading to increased latency and resource wastage.
Innovation Solution
Implement a method where uplink grants are sent only to zero-buffer UEs after serving active UEs with non-zero buffers, ensuring available resources are utilized efficiently by prioritizing higher priority traffic and using remaining resources for zero-buffer UEs, with scheduling managed through Physical Downlink Control Channel and Physical Uplink Shared Channel resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If proactive grants are sent to all UEs to reduce uplink latency, then uplink latency is reduced, but resource wastage increases due to grants allocated to UEs without actual traffic
Solution Approach 1:
The patent applies local quality by differentiating grant allocation based on UE buffer status. Zero-buffer UEs receive grants only when resources remain after serving active UEs, while active UEs with non-zero buffers are served first. This localized differentiation optimizes resource allocation efficiency while reducing uplink latency for UEs that actually need transmission.
Solution Approach 2:
The patent changes the scheduling parameter priority based on buffer status. By introducing a parameter change where zero-buffer UEs are scheduled only after active UEs and when resources remain, the system dynamically adjusts grant allocation behavior to balance latency reduction with resource efficiency.
2Loss of time
If prediction methods are used to send grants to UEs with anticipated data, then uplink latency is reduced, but reliability decreases due to unreliable traffic characteristic prediction
Solution Approach 1:
The patent applies preliminary action by proactively allocating resources to zero-buffer UEs in advance, before they generate traffic. This allows UEs to immediately transmit data when it arrives in the buffer, reducing uplink latency without relying on unreliable prediction of when traffic will occur. The grant is prepared ahead of time but only activated when resources remain after serving active UEs.
3Ease of operation
If resources are allocated to zero-buffer UEs before active UEs, then resource allocation simplicity increases, but productivity decreases due to wasted resources on UEs without traffic
Solution Approach 1:
The patent segments the UE population into two distinct groups: active UEs with non-zero buffers and zero-buffer UEs. This segmentation enables differentiated scheduling where active UEs are served first to ensure resource utilization efficiency, while zero-buffer UEs receive grants only from remaining resources. The segmentation maintains operational simplicity through clear priority rules while improving overall productivity.
Data Source
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AI summary
A method of operating a wireless cellular communication system includes: operating one of an eNB or gNB communicating with a set of user equipments (UEs); and scheduling, using a scheduler, uplink (UL) auto-grants to the set of the UEs when selected resources are available, the selected resources including Physical Downlink Control Channel (PDCCH) resource, Physical Uplink Shared Channel (PUSCH) resource and scheduler capacity. The scheduler determines at least two UEs in RRC-connected mode and having zero UL buffer count, at least one of the two UEs with downlink (DL) traffic present and at least one of the two UEs without DL traffic present. The scheduler selects a set of RRC-connected UEs with zero UL buffer count for which UL auto-grants can be scheduled with a designated number of physical resource blocks (PRBs) and designated Modulation and Coding Scheme (MCS).