Latency-Aware LASO Scheduling for Wireless HCCA and EDCA Access
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Solution Overview
Problem
Current wireless local area networks (WLANs) face challenges in efficiently increasing data throughput and maintaining quality of service for applications like voice over Internet Protocol (IP) telephony and real-time video streaming due to inefficient bandwidth usage in coordinating access to the wireless transmission medium, particularly in meeting delay requirements of Hybrid Coordination Function Channel Access (HCCA) traffic flows.
Innovation Solution
The proposed solution involves a scheduling method that determines access to the wireless transmission medium based on the age of the oldest data packet in each queue, eliminating flows with packets older than a certain threshold and prioritizing those with the smallest sum of maximum age and creation time, switching to Enhanced Distributed Channel Access (EDCA) when all HCCA flows are ineligible, to maximize EDCA access time and meet deadline requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional scheduling methods (EDF or WRR) are used for HCCA traffic flows, then delay requirements can be met, but the amount of time available for EDCA access is reduced
Solution Approach 1:
The patent implements dynamic scheduling by eliminating flows with packets older than a threshold age and prioritizing flows with the smallest sum of maximum age and creation time. This dynamic approach adapts to fluctuating traffic loads and packet ages in real-time, allowing the system to meet delay requirements while maximizing EDCA access time by flexibly adjusting which flows receive HCCA access at any given moment.
Solution Approach 2:
The patent changes the scheduling parameters from static deadline-based or round-robin approaches to age-based parameters. By using packet age, creation time, and the sum of maximum age and creation time as scheduling criteria, the system optimizes both delay satisfaction and EDCA access time. This parameter transformation enables more efficient bandwidth utilization while maintaining quality of service.
2Reliability
If more time is allocated to HCCA access to meet delay requirements, then quality of service improves, but data throughput is reduced due to inefficient bandwidth coordination
Solution Approach 1:
The patent transforms the scheduling approach by using packet age and creation time parameters instead of traditional deadline or round-robin methods. This parameter change enables the system to meet quality of service requirements through age-based prioritization while simultaneously improving data throughput by reducing coordination overhead and optimizing bandwidth allocation efficiency.
Solution Approach 2:
The patent ensures continuous and efficient bandwidth utilization by constantly monitoring packet ages and dynamically adjusting HCCA access grants. This continuous optimization prevents bandwidth idle time and ensures that the wireless transmission medium is efficiently used for productive data transmission rather than coordination overhead.
3Reliability
If collision avoidance techniques are used to coordinate access to the wireless transmission medium, then interference between user stations is reduced, but a considerable amount of bandwidth is consumed in the coordination process
Solution Approach 1:
The patent extracts and eliminates flows with packets exceeding a threshold age from HCCA consideration, allowing the system to focus coordination resources only on flows that currently have packets needing transmission. This extraction reduces the coordination overhead and bandwidth consumption while maintaining interference reduction benefits for active flows.
Solution Approach 2:
The patent applies partial action by not requiring all flows to undergo full coordination procedures. Instead, it selectively applies HCCA access based on packet age criteria, allowing flows with older packets to receive priority treatment while reducing coordination bandwidth consumption for flows with newer packets or those that can wait.
Data Source
AI summary
Traffic flows of data packets from respective packet queues in wireless stations to a shared transmission medium of a wireless network are scheduled in accordance with Hybrid Controlled Channel Access (HCCA) and Enhanced Distributed Channel Access (EDCA). HCCA is applied by eliminating from consideration for HCCA access flows for which the sum of a desired minimum age of an oldest data packet in the respective packet queue and the time of creation of the oldest data packet is greater than the present time. For flows that are not eliminated from consideration, HCCA access is granted to the flow having a smallest sum of the desired maximum age of the oldest data packet and the time of creation of the oldest data packet. When all traffic flows are eliminated from consideration for HCCA access, EDCA is applied so that traffic flows compete for access to the medium.