In the previous code example, we discussed a statically assigned Tasklet via the DECLARE_TASKLET_OLD MACRO. In the current code example, a dynamcally memory allocated tasklet structure is intialized for operation via the tasklet_init function. The “dmesg output” is shown below Workqueues as bottom half method in the Linux kernel

Tasklet is a bottom half processing method. The Tasklet is scheduled from the ISR in this instance. The below code snippet shows a statically initialized Tasklet and the output of the code block The Makefile for the above code is provided below The output of the tasklet being scheduled and the handler being invoked is […]

There are a number of APIs that are defined for Tasklet operation in the Linux kernel. The below table provides a list of Tasklet APIs with a brief description of the APIs. For a more comprehensive list – refer /linux/interrupt.h file in the Linux kernel Tasklet API Description tasklet_init Initialize the tasklet. Used in dynamic […]

Now that we have looked through the TWT MAC settings, TWT element, parameter, request types and Flow type fields in the previous articles, we can look at the flow for an Individual TWT operation and a Broadcast TWT operation from the standard. Individual TWT Operation The steps for the above are outlined as follows A […]

The TWT Setup Command which is part of the TWT parameter set field as shown below can take the below command values TWT Setup Command Value TWT Setup Command Name Command Description 0 Request TWT A TWT requesting or TWT scheduled STA requests to join a TWT without specifying a target wake time. This command […]

Before understanding the operation of TWT, it is important to understand the building blocks of the TWT framework. The below building blocks provide inputs on how the negotiation, setup and operation of a TWT is performed The control field format for the TWT element is updated from 802.11-2020 as depicted The Negotiation Type subfield indicates […]

An High Efficiency 802.11ax station will set the following in its HE Capability Information Element field Parameter Description TWT Requester Support Set to 1 if dot11TWTOptionActivated is true and the STA supports TWT requesting STA functionality Set to 0 otherwise. TWT Responder Support Set to 1 if dot11TWTOptionActivated is true and the STA supports TWT […]

In the earlier 802.11ah standard, a novel power save mechanism targeted to address power save requirements of IoT devices which normally would desire longer sleep times was devised. This method or feature was named as Target Wake Time. In this feature, the Access Point could allow the 802.11 stations to wake up at predefined instances […]

An 802.11ax Station indicates support for PSR based spatial reuse transmission by setting the PSR based SR Support subfield to 1 in the HE PHY capabilities information element. An 802.11ax Station indicates support for PSR based spatial reuse reception by setting the PSR responder subfield to 1 in the HE MAC capabilities Information field in […]

Another method of Spatial Reuse that has been defined in the standard is Parameterized Spatial Reuse (PSR) operation. The operation is dependent on the receive of a PSRR PPDU packet. It is important to understand the definition of PSRR PPDU. What is a PSRR PPDU? The full-form of the PSRR PPDU stands for Parameterized Spatial […]