The evolution of Wi-Fi technologies is marked by big leaps every few years. Starting with 802.11b, then 802.11g, 802.11n, 802.11ac etc, the wheels of innovation have been turning and giving users substantially better speeds and feeds than past generations. We are now on the cusp of a similar such leap: 802.11ax.
802.11ax has been developed with a few specific design goals:
- Improve capacity and client performance in real world high density environments by improving spectral efficiency. This goes beyond the typical speeds and feeds increases of previous generations of Wi-Fi.
- Improve power management for devices like IOT sensors.
- Improve outdoor range and performance for mesh or fixed wireless networks.
Many of these goals are similar what LTE has been trying to achieve as well, since there are similar challenges in that space. The solutions in 802.11ax share some of the learnings and developments happening in the LTE/5G space.
The specific major improvements include:
* OFDMA : Instead of splitting and using the spectrum only in the time domain to transmit and receive frames, with OFDMA also divides the frequency into smaller slices (called Resource Units) which can be used to transmit to clients. Hence a single transmission from the AP can be used to send data to multiple clients, and in the uplink direction multiple clients can co-ordinate a simultaneous transmission together to the AP.
* MU-MIMO: While 802.11ac Wave2 introduced the concept of Multi-User MIMO in the downstream direction, 802.11ax extends it to both up as well as downstream transmissions. In addition from the typical 4x4 MU-MIMO configurations 802.11ax takes it to 8x8 providing even better spectrum usage with larger client groups.
* 1024-QAM Modulation: 802.11ac provided support for 256-QAM, with 802.11ax this is increased to 1024-QAM providing much higher data rates and throughput.
* More Robust Frames: longer OFDM symbols and other preamble updates increase the likelyhood of succesful transmissions, especially in noisy outdoor environments.
* Power Save Mechanisms: Using mechanisms such as Target-Wait-time clients such as IOT sensors can now sleep longer, saving battery life and extending their usability.
Although there are some early products now hitting the market, we expect mid/late next year as the IEEE standard heads towards ratification and Wi-Fi certification begins that we really see adoption of standards compliant and fully interoperable 802.11ax devices start.