Wi-Fi speeds have increased enormously over the past decade, with newer Wi-Fi standards cropping up at regular intervals. With IEEE 802.11ax products in the market, the wireless data transfer speeds have been blazing fast. Cees Links, general manager wireless connectivity, Qorvo talks with Abhimanyu Rathore from EFY about the revolution brought in by the newest Wi-Fi standard.
Q. How has Wi-Fi evolved in regards with the developing wireless ecosystem?
A. The change is fundamental. The evolution of Wi-Fi until now was much focused on raw data rate improvement, from 11 Mb/s in 802.11b, 54 Mb/s in 802.11g to 150Mb/s in 802.11n and close to 1 Gb/s in 802.11ac to maybe multiple Gb/s in 802.11ax.
Q. So, would it be correct to say that the focus is on increasing the data rates?
A. Not exactly. The mind of Wi-Fi is shifting from focusing on raw data rate and requiring maximum output power to get the maximum range to enabling multi-user capacity. The purpose of .11ax is focused on capacity: which is defined as enabling more users simultaneously sharing the same frequency band at the same time to do data intensive tasks. Everyone in the family now can do “their own thing” and is not hindered by activities of anyone else, or in the case of apartment building: not hindered by the Wi-Fi activities of the neighbours.
Q. Why the shift from maximising output power and increasing raw data rates?
A. Originally the tendency was to maximize output power within the legally approved limits. This has its drawbacks, like “polluting” the spectrum at places where this would not be required. Essentially wasting spectrum, reducing system efficiency, and/or forcing other access point to start working at the maximum of their power capability. Not a very sophisticated picture: all devices yelling as loud as possible and trying to listen as best as they could, a rowdy party.
Q. How does 802.11ax handle this problem & is there a downside?
A. Distributed Wi-Fi will force the complete rethinking of building Wi-Fi products. It enables reducing the output power by compartmentalizing the space, more like a civilized reception, where more people can effectively communicate with each other in smaller groups. Even when the reception gets larger and the general “noise level” goes up, communication is still very well possible, without having to yell too loud or listen too hard. Of course, everything has its limitations, also in the Wi-Fi domain, but from this comparison it becomes intuitive, that significant efficiency improvement can be reached, and that is what we have seen in practice.
Q. What is the optimal channel assignment for a certain distributed Wi-Fi configuration?
A. It is just a fact of life, that there is more bandwidth in the higher 5GHz frequency bands, suggesting this band as the preferred choice for the backbone of your Wi-Fi system. However, the range is highly limited in the 5GHz band, practically speaking, about less than half of 2.4 GHz band. For that reason, the 2.4GHz with its better range performance would be the preferred choice for the backbone, but the bandwidth in the 2.4 GHz is lower, which makes it less suitable for the aggregation function as usually performed by backbones. A better way to look at it would be, can “the system” dynamically adapt to changing environment, including the traffic load, and the interference, for instance from the neighbouring systems?
Q. Does 802.11ax handle the balance between increasing raw data rate and optimising performance?
A. This is an interesting technology challenge. Solving this dilemma shows the shifting that .11ax is causing from raw data rate to capacity and opening a complete new avenue of opportunities for differentiation of product builders. Customers care about the best performance, and the highest data rate, wherever they expect, is to be available in their homes.
