Discussion on 802.11ax & “Wi-Fi Re-defined” with Nitin Madan, PLM, Broadcom

802.11ax is all new Wi-Fi standard which looks to redefine the Wi-Fi industry. The standard seems to have solutions for all concerns and limitations posed by the mass deployment of Wi-Fi including hyper dense environment deployments, interference mitigation, scheduling, and power consumption.

Multiple organizations have announced Wi-Fi ax products. Broadcom recently announced that they sampled chipsets for the 802.11ax ecosystem. More about the chipsets and their features can be found at the link below:

http://investors.broadcom.com/phoenix.zhtml?c=203541&p=irol-newsArticle&ID=2293974 

We got the chance to speak to Mr. Nitin Madan, (Product Line Management at Broadcom) about 802.11ax’s key features, roadmap, and how this standard will fit within future networks. Mr. Nitin also shared his views on how 802.11ax will help de-congest the almost saturated Wi-Fi spectrum.

TPO:  Will the whole scenario change once 802.11ax becomes the de-facto Wi-Fi access point standard?

Nitin Madan: Yes indeed, 802.11ax will be a big deal for all wireless, licensed and unlicensed.

TPO: With 802.11ax, the scheduler gets more sophisticated. Does it gets more adaptive and agnostic to technologies on the same spectrum such as Multefire and LTE-U/LAA? Multefire, LTE-U/LAA are still not at the level they were hyped to be, but do you see this changing or will Wi-Fi grow stronger with ax?

Nitin Madan: I think 802.11ax will remain as the communication channel of first resort, while coexisting well with traditional LTE-based solutions due to superior economics of 802.11 based networks. 802.11ax will offer many new business models as well such as Free, Managed Service, Hotspot, Private, etc., while the LTE-based variants allow for subscriber based business models.

Additionally, ax will be an important Radio Access Technology whenever 5G comes around to augment the densification and offloading needs.

Regarding unlicensed versions of LTE technology, coexistence mechanism are being built as we speak. TPO: Do you see 802.11ax to be the technology which changes the access network all together, as it becomes more mature and at par with cellular, does this gives ISP provider or non-spectrum holding agencies to create their network with QOS similar or better than cellular?

Nitin Madan: I think it will be complementary to cellular. I do not think it will have, on average, the QoS that the best cellular connection can provide, but it can be good enough for most mainstream use cases. Additionally, the economics of 802.11ax will be much better which will accelerate some non-traditional telecom models and allow for service provider business model innovation.

TPO: What apart from Scheduler implementation are the most important changes in ax compared to legacy Wlan standards, hence making it better?

Nitin Madan:  802.11ax has a lot of additional features that lead to much higher performance and network capacity.

These include:

• OFDMA – Allows many users to share the spectrum at the same time for uplink and downlink.
• More efficient tone plan increasing speeds.
• More range as devices can use narrow bandwidths and pack more power spectral density.
• TWT increases battery life and capacity as multiple devices can wake up at the same time and share spectrum using OFDMA.
• BSS Coloring – this improves performance in a situation when multiple WiFi networks overlap with each other.
• MU-MIMO

TPO: When do you see ax coming on the device side and actually being utilized as a technology for end to end in real market.

Nitin Madan: Retail Access Points will be available early next year. Phone deployments should start towards end of 2018.

TPO: How do you see the Wi-Fi ecosystem from here as 2.4 and 5GHz are getting saturated, hence there was already need of more sophisticated access points and radio technology? Ax having better scheduling, interference mitigation algorithms would solve the same issues?

Nitin Madan:  Max will help a lot in fighting these congestion issues. In addition to scheduling (TWT), OFDMA would provide huge gains as device can communicate at the same time instead of waiting their turn, hence reducing congestion. This is similar to adding more lanes to a road or highway so that more vehicles can use the road at different speeds vs. a single lane road where the slowest vehicle will block the faster ones.

TPO: In my personal view 5G would be fat backhaul pipe when users are stationary and technologies such as Wi-Fi will be used by all devices and sensors indoors. How does Ax help IoT networks and dense deployments?

Nitin Madan: 5G as currently defined is all things to all people. For some, it is next generation mobile cellular, for others it is about IoT, V2X and network slicing, for yet others, it is also about fixed wireless. I don’t know which direction it will evolve in, but it will take a really long time, as is the case with any major telecom infrastructure upgrade. Max for all the reasons listed in response #1 will help IoT and dense deployments.

https://www.linkedin.com/pulse/5g-new-back-haul-rather-than-primary-access-technology-rahul-atri

TPO: Did you or the team perform any study on how ax is better acquitted with interference mitigation and management wrt technologies on the same band compared to legacy standards? Would love to have some information on the same.

Nitin Madan: 802.11ax along with other Wi-Fi technologies such as OCE will reduce OTA management overhead, and along with OFDMA, will free up airtime creating less interference. Additionally, BSS coloring will allow devices to set CCA thresholds dynamically so that they can communicate even in the presence of some interference. We have done some studies on this and find massive improvements in deployments such as dense apartment buildings.

TPO: Typical features such as higher modulation, MU-MIMO etc. don’t work very well in mobile scenarios and when there are more users. Does the same happen with ax? Are there any special features to meet and achieve QoS for hyper dense environments?

Nitin Madan: Higher modulations are very effective if the range is smaller. In this case, the device can use 1024-QAM, finish its communication quickly and leave the channel empty for another device to communicate.

MU-MIMO is very effective but can be limited by the number of antennae available at the AP and STA – if there are many more devices with a variety of speed requirements OFDMA can provide more performance boost than MU-MIMO alone. Higher capacity as delivered by 802.11ax will always lead to better average QoS.