BSS Coloring (Basic Service Set Coloring)

BSS Coloring is a mechanism introduced in Wi-Fi 6 (IEEE 802.11ax) that helps mitigate interference in environments with overlapping Wi-Fi networks. Each Basic Service Set (BSS) is assigned a unique color identifier, allowing stations to differentiate between intra-BSS and inter-BSS transmissions—even when they operate on the same channel.

Scope and Application

BSS Coloring is part of the IEEE 802.11ax standard and improves spatial reuse in high-density deployments. It is especially relevant in environments where multiple access points share the same channel and operate within overlapping coverage areas.

Typical use cases:

• Apartment buildings with multiple private networks

• Office spaces with high AP density

• Industrial or campus-wide Wi-Fi deployments

The function is typically activated in conjunction with spatial reuse mechanisms and Clear Channel Assessment (CCA) threshold adjustments.

Key Technical Characteristics

• Color Assignment
  Each BSS is assigned a 6-bit color identifier. Frames include this identifier to distinguish transmissions from neighboring BSSs.

• Interference Differentiation
  Stations use the BSS color to decide whether overlapping transmissions should be deferred or ignored based on predefined energy detection thresholds.

• Dynamic Updates
  The color value can be updated dynamically to avoid conflicts with neighboring networks, a process sometimes referred to as "color collision detection."

Performance Impact

BSS Coloring enables more aggressive reuse of the wireless medium, reducing the number of unnecessary transmission deferrals. It contributes to:

• Higher throughput in congested environments

• Better overall channel efficiency

• Reduced latency in dense deployments

Regulatory Context

BSS Coloring is defined in the IEEE 802.11ax standard and has no direct regulatory implications. However, it is part of the Wi-Fi CERTIFIED 6 test suite and may influence test behavior in coexistence scenarios. The feature does not affect transmit power limits or frequency use but supports more efficient spectrum utilization under existing regulatory constraints.

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