What is Orthogonal Frequency Division Multiple Access (OFDMA)?

What Is OFDMA in WiFi?

OFDMA, or Orthogonal Frequency Division Multiple Access, is a technology in WiFi 6 (802.11ax) and WiFi 7 (802.11be). The purpose of this technology is to allow a single OFDMA-enabled router to communicate simultaneously with multiple devices.

To better understand why the OFDMA WiFi technology exists, you can imagine a single-lane road where only one car can pass at a time. Any obstruction on the road that causes any of the cars currently driving on it to slow down or stop will delay all other cars on the same road. That's not ideal considering how many users are typically connected to the same router these days. Unfortunately, that's exactly how older routers work.

When you enable OFDMA on your WiFi 6 or WiFi 7 router, you essentially increase the number of available lanes for cars to drive on, allowing multiple devices to communicate with the router at the same time without the possibility of one device slowing down all other devices.

What's the Difference Between OFDM and OFDMA?

Before OFDMA there was OFDM (Orthogonal Frequency Division Multiplexing). Both of these WiFi technologies are designed to improve the efficiency and reliability of wireless communication, but OFDMA takes things to the next level by allowing more than one device to transmit data at the same time.

Advantages and Disadvantages of OFDMA

OFDMA is often described as the most important technology enhancement introduced in WiFi 6 because it offers many useful benefits. That said, the technology also has a few downsides you should be aware of.

Advantages

• Lower latency: Arguably the biggest advantage of OFDMA routers is their reduced latency, which is especially important in real-time applications such as IoT, online gaming, or audio/video conferencing.
• Higher throughput: By dividing a single channel into multiple subcarriers and assigning them to different users, OFDMA can increase the total maximum throughput of a network.
• Increased network capacity: By allowing multiple users to simultaneously transmit and receive data, OFDMA can increase network capacity, allowing for more devices to connect to a network without compromising performance.
• Improved power efficiency: OFDMA can help reduce power consumption in mobile devices by enabling them to transmit and receive data more efficiently, leading to longer battery life.
• Backward compatibility: When you enable OFDMA on your wireless router, you don't prevent legacy devices that don't support WiFi 6 or WiFi 7 from connecting to your network.

Downsides

• Requires a WiFi 6 or newer router: OFDMA is a feature of the WiFi 6 (802.11ax) standard and is not supported by older routers. As such, you may need to purchase a new router to take advantage of it.
• Higher CPU usage: The increased complexity of OFDMA compared with OFDM means that OFDMA-enabled routers need beefier CPUs to process the same amount of data.

Of course, the advantages of OFDMA will manifest only if your wireless network is designed and implemented correctly. That's why you should always perform a wireless network assessment using an easy-to-use WiFi analyzer app like NetSpot.

With the help of NetSpot, you can perform a site survey to identify the perfect location for your router, and you can also analyze other networks in your area so that you know how to adjust your network settings in order to reduce signal interference.