The below figure taken from the standard illustrates OBSS PD operation in 802.11ax: The above steps for STA SR S2 is best described from the standard and is posted below (from the 802.11ax standard): Receives the PPDU from S1 and, if it classifies the PPDU as inter-BSS PPDU, ignores the PPDU using OBSS PD-based spatial […]

When a non-AP Station determines to set an OBSS PD level and ignores an OBSS packet according to the rules defined by the 802.11ax standard, the 802.11 station has to begin an “OBSS PD SR transmit power restriction” period. The transmit power restriction period will be terminated once the current TX opportunity that the station […]

The 802.11ax standard which adheres to OBSS PD operation should also conform to certain minimum and maximum OBSS PD levels and transmit power constraints. The station should conform to operate within the OBSS PD min/max values and also cannot transmit at the maximum power it is possible to transmit a packet. The transmit power is […]

The below 802.11ax describes the basic rules and checks to not update the Basic NAV timer or issue a PHY Reset for a OBSS SRG PD Level. The standard also defines further “NOTES” which define SRG OBSS-PD operation in the same section (Section 26.10.2.3 802.11ax standard). The interested reader should go through the section. OBSS […]

The 802.11ax describes the following operation for PHYreset for a detected OBSS packet or not update the Station’s Basic NAV timer based on the below rules maintaining a non-SRG OBSS PD Level: There are further “NOTES” provided which describes non-SRG operation in 802.11ax in the same section (section 26.10.2.2 of the 802.11ax standard). The interested […]

For the interested reader – refer Spatial Reuse Operation and Spatial Reuse Groups for a brief on the idea of spatial reuse and what a spatial group consists of. As we discussed in the earlier articles, It is possible to configure a different Carrier Sense Threshold for Overlapping BSS such that the Signal detect threshold […]

The standard defines rules for identifying whether a received packet is an SRG PPDU or a non-SRG PPDU. The section 26.2.3 SRG PPDU identification describes the different operations that a non-AP Station will perform to identify a received packet as SRG packet. If the below conditions fail, the packet is deemed a non-SRG packet. OBSS […]

A spatial Reuse group is banding together of different OBSS into a common group where common specific Spatial Reuse Group (SRG) OBSS Packet Detect (PD) value can be configured for detection of OBSS packets. By placing the different BSSes in the same channel sense threshold for OBSS transmission, the co-channel interference as seen from the […]

We have seen in a previous article that BSS Color is used in identifying the BSS a 802.11 packet receiving station is connected to. Spatial reuse operation is a method to use the BSS color for inter-BSS Packet detection and to adapt the station to function better in dense deployment conditions suffering from co-channel interference. […]

A non-AP 802.11ax station will maintain 2 NAVs. An 802.11ax Access Point may maintain 2 NAVs. The two NAVs are defined as below: Basic NAV – NAV maintained and updated by an Inter- PPDU packet reception Inter-BSS NAV – NAV maintained and updated on receipt of an Inter-PPDU packet reception or an 802.11 packet reception […]