WLAN Data Link Layer

The data link layer of WLAN is used as the key layer for data transmission. To understand WLAN, you also need to know it in detail. Through the following explanations:
In the protocol of IEEE 802.11, its MAC sublayer contains the media access mechanisms of DCF and PCF: 
Meaning of DCF: Distributed Coordination Function 
While DCF is the basic access method of IEEE 802.11 MAC, which adopts CSMA/CA technology and belongs to the competitive method, when this node sends data, it will monitor the channel. Only when the channel is idle can it send data. Once the channel is idle, the node will wait for a specified time interval between DIFS. 
If the transmission of other nodes is not heard before the end of DIFS, a random backoff time is calculated, which is equivalent to setting a backoff time timer; 
The node detects the channel every time it experiences a time slot: if it detects that the channel is idle, the backoff timer continues to time; otherwise, the remaining time of the backoff timer is frozen, and the node waits again for the channel to become idle; after the time DIFS elapses, the node continues to count down from the remaining time; If the time of the backoff timer decreases to zero, the whole data frame will be sent. This is the rectification process of data transmission. 
PCF: Point Coordination Function;
PCF provides a point coordinator to poll all sites for sending or receiving data. This is a noncompetitive method, so frame collisions will not occur, but it can only be used in wireless local area networks with certain infrastructures.
The above is the introduction of the WLAN Data Link Layer brought by Shenzhen Haidiwei Optoelectronics Technology Co., Ltd. Shenzhen HDV Phoelectron Technology Co., Ltd. is a manufacturer specializing in optical communication equipment, and its communication products.