The Wireless Broadband Alliance (WBA) has baked a tray of deployment guidelines for WiFi 6 (802.11ax), iced with a set of scenarios for the next generation WiFi technology rolling out later this year. It intends to familiarize service providers with the taste of WiFi 6 in this critical period amid 5G network roll outs, but have too many cooks spoiled the broth?
For the sake of brevity, let’s jump straight into a case study with Boingo Wireless. The US mobile ISP has been trialing WiFi 6 at John Wayne Airport, deploying Cisco WiFi 6 technology to allow airport staff to carry out day-to-day admin tasks as well as streaming high bandwidth content on pre-release Samsung Galaxy S10 handsets fitted with WiFi 6 chipsets – reporting high data rates, ultrafast speeds, and no buffering.
Unfortunately, the Boingo case study is missing any actual data and comparisons with the technology’s predecessor WiFi 5 or indeed other versions, although the trial will continue to explore new uses, particularly with meeting key 5G requirements to power a range of connected use cases in dense environments.
To the guidelines now, which are rather convoluted, as you might expect from an engineer-authored report. Guidelines cover four broad topics, spanning RF planning and design, infrastructure SLAs, seamless mobility, and preparing for co-existence. The 40-page whitepaper published this week has poured the most effort into infrastructure SLAs, detailing all 12 SLAs that the network infrastructure can be measured against, so that’s where we’ll start, looking at a handful of the most significant.
WiFi 6 is designed to significantly improve the performance of a number of concurrent users with multiple specific design principles, which impacts heavily on the number of business support systems (BSS) and backhaul requirements for a given coverage. The introduction of uplink multiple user access, including both UL OFDMA (Uplink Orthogonal Frequency Division Multiple Access) and UL MU-MIMO, will especially enable more concurrent accesses to the radio resources, according to the WBA.
UL OFDMA and UL MU-MIMO are cited throughout the report, credited for boosting power and range, with higher spectral efficiency, for example providing ideal for use in stadium builds given the increased demand for video upload, where it is common to limit the end user to speeds to just 2 Mbps to 5 Mbps.
However, when detailing packet loss, the WBA warns that if even a single station is unable to adhere to the maximum allowed time or frequency offset, then the access point (AP) will not be able to decode either of the set of high efficiency trigger-based PLCP Protocol Data Unit from multiple users in response to a trigger frame. In other words, the entire UL OFDMA frame exchange will be regarded as corrupted and need retransmissions.
So, as we know, WiFi 6 will include latency-reducing techniques like OFDMA, a battery saving technique called Target Wake Time, and of course MU-MIMO which can increase capacity when serving a small number of high bandwidth clients – ideal for managed services such as high-bandwidth video applications operating in the 5 GHz band.
Meanwhile, because 2.4 GHz is often congested with legacy clients (802.11b/g/n), the WBA says when (or if) the 6 GHz band becomes available, it will extend the 5 GHz band to free up unprecedented capacity for gigabit broadband access, allowing WiFi 6 to serve next generation mission critical applications.
Now let’s get into the juicy deployment scenarios. The report cites massive investment in the US to upgrade cable networks, having recently launched the 10G initiative with 80% of cable gigabit services now available to 80% of housing units, as a critical reason why subscribers must experience the enhanced speed on the wireless network too.
Keeping with residential, the WBA cites non-managed MDUs as the most challenging environment. This is due to rogue overlapping APs, ever-changing channel configuration and a higher client density. It advises multi-AP set ups for larger premises running the EasyMesh standard for facilitation of client and band steering, while defining a communications protocol for easy onboarding, provisioning, control and automated management of APs.
As with any new standard, WiFi 6 guidelines will grow as field trials are executed, producing results to evolve the technology accordingly.