Battery power is a precious resource and various mechanisms have been introduced in the 802.11 standard to protect the same. The VHT TXOP power save feature is one such feature. TXOP stands for – Transmit Opportunity. All 802.11 stations (Access Point as well as non-Access Point stations) contend for the medium as per EDCA rules […]

Medium Access Layer (MAC Layer) State-machines need to interact with the PHY Layer to meet certain Physical Medium dependent (PMD) restrictions. The Parameter list which defines the MAC-PHY interface is the Txvector and Rxvector parameters. The Txvector and Rxvector Parameter list are defined in the PHY specific parameter list of each PHY sub-clause in the […]

802.11 Radios consume a lot of power. Hence, a lot of time and effort has been expended in the area of 802.11 Power Save to make the 802.11 Devices more energy efficient. Spatial Multiplexing Power save is one such methodology which allows the 802.11 device to save more power. The 802.11 Standard in 802.11n and […]

The interested reader can get an overview of the Spatial Multiplexing feature here <Spatial Multiplexing Power Save>. Dynamic SMPS In Dynamic SMPS mechanism, an 802.11 station enables its multiple receive chains on receiving a frame addressed to it. The First frame so received shall be a single spatial stream individually addressed frame that requires immediate […]

The interested reader can refer Spatial Multiplexing Power save here <Spatial Multiplexing Power Save> The SM Power-Save Action frame can be used to change the current SM Power-Save Configuration When the 802.11 Station needs to change the Antenna configuration – it sends a SM Power-Save action frame to the Access point indicating a change in […]

The Reverse Direction Grant feature was introduced in 802.11n. The Reverse direction grant was a feature which would allow for better usage of a Transmit opportunity (TXOP) as defined in WMM/EDCA. The need for Reverse Direction Grant (RDG) was felt as described in the next paragraph. The WMM/EDCA mechanism allowed for an 802.11 station to […]

For the Revere Direction Protocol to work – both the Transmitter and the receiver 802.11 stations need to support Reverse Direction Grant. 802.11 stations supporting Reverse Direction Grant would broadcast their support in the HT Capabilities element – RD Responder field. The HT capabilities element and the RD-Responder field present in the HT-Extended capabilities Info […]

The interested reader can look at an overview of Management Frame Protection in the following article<Management Frame Protection> Management Frame Protection is indicated in the 802.11 frames in the following manner. The RSN Capabilities indicate that the management protection is enabled. Management Frame Protection Required True (set to 1) – Management Frame Protection is required […]

In 802.11, data frames could be transmitted with encryption but management frames were always sent in the open (no encryption). The 802.11w standard amendment introduced management frame protection and the feature is deemed mandatory by the Wi-Fi alliance from 802.11ac onwards. The Management Frame protection would incorporate management frames that are transmitted after the AP […]

Broadcast Integrity protocol provides data integrity and replay protection to broadcast/multicast robust management frames. An IGTKSA (Integrity Group Temporal Key Security Association) should be established and an IGTK (Integrity Group Temporal Key) should be available for encrypting the Broadcast/Multicast frames. Let us take a brief look at the BIP frame format, Management MIC Element and […]