[Summary] Brief Review of RTS and CTS in WiFi

Communication ProtocolRTS/CTSProtocol: The request sending/allowed sending protocol, which is equivalent to a handshake protocol and mainly used to solve the "hidden terminal" problem. "Hidden terminals" (hidden stations) means that base station a sends information to Base Station B, and base station C does not detect that a also sends information to B, so both A and C send signals to B at the same time, as a result, all signals sent to B are lost. "Hidden terminals" mostly occur in large units (usually in outdoor environments), which results in efficiency loss and requires an error recovery mechanism. When you need to transfer large-capacity files, especially to prevent the occurrence of the "hidden terminal" phenomenon.

Provides the following solutions. In parameter configuration, if you useRTS/CTSProtocol, and set the maximum number of bytes to be transferred-once the data to be transferred exceeds this upper limit, the RTS/CTS handshake protocol is started: first, a sends the RTS signal to B, it indicates that a needs to send some data to B. After B receives the RTS, it sends the CTS signal to all base stations, indicating that a is ready for sending, the rest of the base stations that want to send data to B will suspend sending; the two sides will start real data transmission only after the successful exchange of the RTS/CTS signal (that is, the handshake is completed, when multiple mutually invisible sending sites send signals to the same receiving site at the same time, they can only be sent by the site that receives the site response CTS, avoiding conflicts. Even if a conflict occurs, it is only when you send the RTS message. In this case, because you cannot receive the CTS message from the website, you can use it again.DCFThe competition mechanism provided by the protocol allocates a random out-of-time value, waiting for the next idle MediaDIFs(Distributed
Inter-frame space) and then compete to send the RTS until it is successful.