Communication Devices Using Constrained Contention for Scheduled Access
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Scheduled intervals in wireless communication systems are vulnerable to disruptions from stations within the same or overlapping basic service sets (BSSs) that do not respect or are unaware of these intervals, leading to delays and interference during low latency traffic exchanges.
Innovation Solution
The introduction of a constrained contention frame (CCF) is used to protect scheduling intervals by preventing unauthorized channel access during critical periods, allowing scheduled stations to access while deferring or deprioritizing non-scheduled stations, with mechanisms that do not require extensive cooperation between access points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If scheduled intervals are introduced for low latency traffic, then latency and jitter are improved, but the system becomes vulnerable to interference from unscheduled stations
Solution Approach 1:
The access point transmits a control frame before the scheduled interval begins, indicating the upcoming scheduled period and requesting other stations to defer channel access. This preliminary action prevents unscheduled stations from contending for the channel during critical low latency transmissions, ensuring the scheduled interval proceeds without interference while maintaining the latency improvements.
2Reliability
If scheduled intervals are protected from interference, then reliability of low latency traffic is improved, but channel access fairness may deteriorate
Solution Approach 1:
The control frame includes specific information identifying which stations are scheduled during the upcoming interval. Unscheduled stations can defer access during these protected periods while maintaining normal channel access rights during non-scheduled times. This localized differentiation ensures reliability for scheduled traffic without permanently disadvantaging unscheduled stations, preserving overall channel access fairness.
3Reliability
If control frames are transmitted to protect scheduled intervals, then interference is reduced, but additional overhead is introduced
Solution Approach 1:
The control frame serves multiple functions simultaneously: it announces the upcoming scheduled interval, requests deferral of channel access from unscheduled stations, and provides timing information for synchronized operation. By consolidating these functions into a single frame type, the overhead is minimized while achieving comprehensive protection for scheduled intervals.
Data Source
Figure 1
Figure 2~4
Figure 5
AI summary
A first communication device that is configured to communicate with one or more third communication devices and that comprises circuitry configured to contend for channel access, within an interval before the start or at the start of a scheduling interval during which communication of the first communication device with the one or more third communication devices is planned over said channel; and transmit, after successful contention, a control frame initiating a constrained contention interval and including constrained contention information, the constrained contention interval representing a time period before and/or during the scheduling interval, during which second and/or third communication devices shall either consider the channel as busy or may contend and access said channel according to constrained contention information.