Channel Scheduling for Spatial Reuse in Overlapping Wireless Networks
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Solution Overview
Problem
In wireless networks, overlapping RF coverage areas between adjacent access points can lead to channel collisions, especially when a less sensitive Clear Channel Assessment (CCA) threshold is used for frames transmitted in overlapping areas, resulting in reduced simultaneous transmission efficiency.
Innovation Solution
The network device determines overlapping areas and clients within them, synchronizes clocks with adjacent devices, and negotiates the allocation of overlapping access windows, forbidden windows, and non-overlapping access windows to control frame transmission and minimize channel collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a less sensitive CCA threshold is used for frames transmitted in overlapping areas, then more simultaneous transmissions can be enabled, but channel collisions increase
Solution Approach 1:
The overlapping RF coverage area is segmented into multiple non-overlapping sub-channels through frequency division. Each sub-channel is allocated to specific APs to avoid interference, allowing simultaneous transmissions without collisions by dividing the shared medium into dedicated segments.
Solution Approach 2:
Different CCA thresholds are applied locally based on the specific overlapping relationship between APs. Instead of using a uniform threshold, each AP configures its CCA threshold according to its local interference environment and allocated sub-channels, optimizing simultaneous transmissions while preventing collisions in each local context.
2Object-affected harmful factors
If synchronized operation is implemented to eliminate inter-BSS interference, then channel collisions are reduced, but system complexity increases
Solution Approach 1:
A sub-channel allocation mechanism acts as an intermediary between APs in overlapping BSSs. Instead of direct time synchronization, APs use the allocated sub-channels as a mediator to coordinate transmissions, eliminating inter-BSS interference through frequency separation rather than temporal coordination.
3Manufacturing precision
If clock synchronization is performed between adjacent network devices, then channel scheduling accuracy is improved, but communication overhead increases
Solution Approach 1:
Sub-channel allocations are predetermined and configured in advance based on the overlapping relationships between APs. This preliminary action eliminates the need for real-time clock synchronization during operation, as the non-overlapping sub-channel assignments inherently prevent collisions without requiring continuous coordination.
Data Source
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AI summary
An example device comprising: a processor to determine that a client device is located in an overlapping area between the first network device and a second network device, to synchronize a first clock of the first network device with a second clock of the second network device, to negotiate, with the second network device, a overlapping access window, an overlapping forbidden window, and a non-overlapping access window for the first network device and the second network device in beacon intervals, to allocate the overlapping access window, the overlapping forbidden window, and the non-overlapping access window by the first network device, to store the allocated overlapping access window, the allocated overlapping forbidden window, and the allocated non-overlapping access window as channel scheduling rules for spatial reuse, and to control frame transmission of the network device based on the channel scheduling rules.