BSS Color Scheduling for OBSS Interference in Dense WLANs
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Solution Overview
Problem
Dense WLAN deployments face significant performance issues due to interference, congestion, and low throughput, with existing WLAN features like IEEE 802.11ah not being well suited for such environments.
Innovation Solution
Implementing enhanced BSS color format and associated mechanisms that utilize orthogonal frequency division multiplexing (OFDM), orthogonal frequency division multiple access (OFDMA), BSS silencing, interference avoidance with sectored transmission, or OFDMA with band silencing, allowing stations to determine OBSS information and transmit schemes, and adjust channel availability based on interference robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing WLAN features (e.g., IEEE 802.11ah) are used in dense deployments, then device compatibility and basic functionality are maintained, but performance deteriorates due to interference, congestion, and low throughput
Solution Approach 1:
The patent segments the wireless medium by introducing BSS color coding that allows stations to identify and differentiate between transmissions from their own BSS versus overlapping BSSs. This segmentation enables selective interference handling where stations can prioritize their own BSS transmissions while managing OBSS interference through mechanisms like OBSS PD and spatial reuse, thereby improving throughput in dense deployments
Solution Approach 2:
The patent applies local quality by allowing different transmission parameters and interference tolerance levels for different spatial regions and BSS contexts. Stations can adjust their clear channel assessment thresholds and transmission powers based on local interference conditions and BSS color identification, optimizing performance for specific local environments rather than using uniform parameters network-wide
2Quantity of substance
If more stations and access points are added to WLAN networks, then network coverage and capacity are expanded, but performance deteriorates due to congestion and interference
Solution Approach 1:
By segmenting the network into color-coded BSSs, the patent enables denser deployment of access points without proportional degradation in throughput. Each BSS can operate semi-independently with its own color identifier, allowing stations to quickly identify and prioritize their own BSS traffic while managing interference from other colored BSSs, thus supporting higher device counts with maintained performance
Solution Approach 2:
The patent introduces dynamic parameters including OBSS PD (preamble detection) thresholds and spatial reuse factors that can be adjusted based on current network conditions, BSS color identification, and interference levels. This dynamic adaptation allows the network to optimize throughput as device density changes, rather than degrading linearly with added devices
3Productivity
If enhanced BSS color format and OBSS information mechanisms are implemented, then interference management and spectral efficiency are improved, but device complexity and implementation requirements increase
Solution Approach 1:
The patent extracts essential OBSS information (such as BSS color, transmission parameters, and interference characteristics) from full packet decoding and processes only the critical preamble and color fields. This extraction approach allows stations to identify OBSS transmissions and apply appropriate interference management without the complexity of fully decoding and processing every OBSS packet, thus improving spectral efficiency with controlled complexity increase
Solution Approach 2:
The patent implements preliminary action by pre-configuring BSS color codes and transmission parameters before deployments. Stations can pre-process and cache BSS color information from beacons and probe responses, enabling faster real-time decision-making about channel access and interference management without complex runtime calculations, thereby improving spectral efficiency with manageable implementation complexity
Data Source
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AI summary
Systems, methods and instrumentalities are disclosed to transmission scheduling. A station (STA) in its own basic service set (BSS) receiving a transmission frame from an overlapping BSS (OBSS). The STA may decode preamble of the received transmission frame. The STA may determine, for example, using the decoded preamble that OBSS information and transmit scheme associated with the OBSS. On a condition that the transmit scheme associated with the OBSS is orthogonal frequency divisional multiple access (OFDMA), the STA in its own BSS may indicate to its access point (AP) that one or more channels or sub-channels that are available or not available for transmission. On a condition that the transmit scheme determined from the preamble of the transmission frame is orthogonal frequency divisional multiplexing (OFDM), the STA may determine that a channel is not available for transmission. The STA may set the channel to busy or idle.