RAN Packet Scheduling with Virtual Queue Control for Low Jitter
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Solution Overview
Problem
Existing scheduling methods for radio access networks fail to efficiently and fairly allocate spectral resources to distributed real-time applications, leading to high latency and jitter, and do not fully utilize available link capacity without disadvantaging other connections.
Innovation Solution
A scheduler allocates more spectral resources than fair share to distributed real-time applications, adjusts a target data rate with an offset above the best effort bitrate, and dynamically adjusts this offset based on time-averaged deviations to maintain a low latency and jitter, ensuring the application functions properly while utilizing the link capacity fully.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the scheduler allocates spectral resources to multiple competing applications, then the spectral resources are distributed among applications, but the link capacity cannot be fully utilized and latency increases
Solution Approach 1:
The scheduler dynamically adjusts the virtual queue size based on the data rate adjustment behavior observed from the distributed real-time application. By making the queue size adaptive rather than static, the system can optimize resource allocation efficiency while maintaining low latency for time-critical applications.
Solution Approach 2:
The scheduler uses feedback from the application's data rate adjustment behavior to adaptively control the virtual queue size. This closed-loop approach allows the system to learn from application responses and optimize both resource utilization and latency performance over time.
2Loss of time
If the scheduler increases the virtual queue size to reduce latency, then the latency and jitter decrease, but the link capacity utilization decreases
Solution Approach 1:
The virtual queue size is made dynamic and adaptive rather than fixed. The scheduler adjusts the queue size based on observed application behavior and feedback, allowing the system to optimize both latency and link capacity utilization under different operating conditions.
Solution Approach 2:
The scheduler changes the virtual queue size parameter based on feedback from the application's data rate adjustment behavior. This parameter adaptation allows the system to balance between low latency requirements and high link capacity utilization.
3Adaptability or versatility
If the scheduler allocates spectral resources fairly among competing applications, then fairness is achieved, but the distributed real-time application experiences high latency and jitter
Solution Approach 1:
The scheduler segments the resource allocation mechanism by introducing a virtual queue that operates separately from the physical queue. This segmentation allows different scheduling strategies to be applied: fair allocation at the resource allocation level while providing priority treatment at the queue processing level for time-critical applications.
Solution Approach 2:
The virtual queue acts as an intermediary layer between the fair spectral resource allocation and the actual data transmission. This intermediary allows the system to maintain fairness in resource distribution while providing specialized handling for real-time applications that require low latency.
4Speed
If the scheduler signals a high target bitrate to the application, then the application can achieve high data rates, but queue overflow occurs causing increased latency and jitter
Solution Approach 1:
The scheduler performs preliminary actions by adaptively adjusting the virtual queue size before queue overflow can occur. By proactively controlling the queue size based on feedback from the application's behavior, the system prevents overflow conditions that would cause latency and jitter increases.
Solution Approach 2:
The adaptive virtual queue size provides a cushioning effect that prevents queue overflow. By adjusting the queue size in advance based on observed application behavior, the system creates a buffer that absorbs traffic variations without causing overflow-induced latency.
Data Source
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AI summary
A method for operating a scheduler of an access point of a radio access network, RAN, wherein a scheduler of a RAN allocates spectral resources to a wireless connection provided by the access point and forwards data packets transmitted by a distributed real-time application via the wireless connection and the distributed real-time application dynamically adjusts a data rate of the transmitted data packets below a target bitrate signaled to the distributed real-time application by the scheduler, the target bitrate being determined by the scheduler as an output bitrate of a virtual queue defined by the scheduler; an access point for a RAN and a computer program product.