Benefits of 802.11ax
Orthogonal Frequency Division Multiple Access - this is the new modulation technique introduced with 802.11ax and replaces OFDM that has been around since 802.11a. This is the same modulation used by cell phone carriers to transmit data to and from your cell phone. This modulation assigns each client resources units (RU) that can dynamically change based on the application needs of the client. Without going too in depth, I’ll use an analogy to show the difference between OFDM and OFDMA – OFDM would be the equivalent to driving a country road and getting to a one lane bridge and OFDMA would equate to a multi-lane interstate. When driving the country road, it doesn’t matter what you drive or how fast you go, if it isn’t your turn to cross the bridge, you aren’t moving. In OFDM, only one device can transmit at a time. If 2 vehicles crossed that bridge at the same time, they have a collision and then all the cars waiting are now affected. The same is true for OFDM. If two clients try to transmit at the same time, such as a hidden node, the frames from the clients will be corrupt and will have to retransmit. Constant retransmissions eat away available airtime for other clients and therefore slow your wireless network down. In contrast, OFDMA is like a huge multi-lane interstate where you have lanes for the fast cars and the slow cars. You even have enough lanes for the wide load trucks to occupy 2 lanes without impacting the flow of traffic. OFDMA lets multiple clients send and receive data at the same time. This is done by breaking one channel into a lot of subchannels or resource units (RU). The AP can then dynamically assign RUs to each client based on their needs. This is a much more efficient way to transfer data over the air and aggregate throughput in a wireless network will increase greatly over an 802.11ac network.