Wi-Fi 6E General Thoughts, and Comparison of Indoor AP Models

General Thoughts on MU-MIMO, OFDMA, and Multi-Gigabit in the 6 GHz Era

While 802.11ac wave 2, Wi-Fi 6, and Wi-Fi 6E all support MU-MIMO, with the intention of talking downstream (and later upstream) to multiple clients simultaneously by taking advantage of the wavelength offset spacing between antenna elements.   In practice, there are too many things that have to go “just right” in the operation of MU-MIMO, posted in previous blogs and presentations, that make it fundamentally impractical in unlicensed bands in general, especially with a lot of external interference from third party neighbors and backwards compatibility support for older Wi-Fi generations.   

 

Wi-Fi 6 introduced OFDMA, which carves up the channel into multiple sub-channels to talk to multiple clients simultaneously.  Again, in crowded unlicensed bands and the requirement to support backwards compatibility to older Wi-Fi generations, the opportunities to perform OFDMA is limited, and even when OFDMA can be made to work, it is carving up a channel into smaller sub-channels, so does not really add airtime capacity.   

 

Hence, while Wi-Fi 6 APs started to support multi-gigabit Ethernet interfaces in higher end AP models, it was impractical to achieve sufficient wireless traffic to require a > 1 Gbps wired interface to the network.   

 

With Wi-Fi 6E, I will acknowledge that supporting backwards compatibility is thankfully no longer an issue with 6 GHz, and the 6 GHz environment is certainly more pristine from an RF perspective.  However, I’m still of the opinion that MU-MIMO and OFDMA are still likely to only offer, at best, only modest gains on the 6 GHz band, ever decreasing as all of your neighbors also start upgrading their Wi-Fi networks to utilize 6 GHz and we are back to the same co-channel interference issues we suffer on 2.4 GHz and 5 GHz.  That said, adding up to 1200 MHz of spectrum and being able to use 40 MHz or 80 MHz channels in a practical sense in most environments will have a direct impact on available AP throughput.   Nonetheless, I’m not yet convinced that most Wi-Fi 6E networks will see wired bandwidths exceeding 1 Gbps per AP.   The bottleneck of any network is the available Internet bandwidth, and only very large venues are currently investing in bandwidth for the site that exceeds 10 Gbps, with most small to medium venues not even exceeding 1 Gbps.   Hence, the multi-gigabit interfaces for Wi-Fi 6E are, at best, only going to be of practical benefit in venues with very high client densities with very high Internet bandwidth capacity, such as stadiums and universities. 

 

Comparison of Common Enterprise Indoor Wi-Fi 6E AP Models 

I have already started proposing several indoor, and a few outdoor, 6 GHz deployments for small, medium, and large venues.  Working in a mostly “vendor-neutral” environment, I have been evaluating the indoor APs currently available from multiple vendors, namely Aruba, Ruckus, Meraki, and Extreme.   

 

While all undoubtedly based on the same set of core chipsets, there are some very distinctive strategic differences in the vendor implementations.  While it is very refreshing to see the vendors moving to differentiate themselves further based on particular features and capabilities, it makes it harder to compare “equivalent” AP models from different vendors. 

 

Why no outdoor APs:  As of the date of this blog, all of the vendors (with one exception) have only released indoor APs (with one exception, noted below).  While the vendors have outdoor Wi-Fi 6E APs (or in at least one case skipping ahead to Wi-Fi 7) on their roadmap, they are all awaiting the FCC to provide official approval of the AFC providers before the APs can be certified by the FCC for sale in the USA, so these APs are not likely to reach the USA market until late 2023 / early 2024.   

 

The notable exception to this is Extreme Networks, with their AP5050 series.  (Update 3/8/2023: Thanks to Chris Kelly @WiFiFrood for catching an error in the particular model in an earlier version of this post.) The catch: this AP has its 6 GHz radio disabled in firmware and does not yet have FCC certification on that 6 GHz radio.  Extreme is making the strategic gamble to get integrators to install the AP now, and then just upgrade the firmware to enable 6 GHz functionality once AFC is settled and they have FCC certification for the 6 GHz radio.  This offering is not without risk to both Extreme and its customers in case the “idle 6 GHz hardware” cannot get FCC certified due to a fundamental hardware flaw or incompatibility with the final FCC rules, though it is a “high risk, high reward” strategy that shows innovative and refreshing market differentiation between the major AP vendors.

 

Hence, here are my own notes on the indoor APs available from Aruba, Ruckus, Meraki, and Extreme. I work with all of these vendors on various projects.  While I note some interesting differences between their "comparable" models, I'm generally reserving judgement as to whether those differences are better or worse.   The key areas of distinction relate to how the vendors choose (or don't choose) to maintain compatibility with 802.3at for their highest end APs.  

 

• Aruba

• AP-615:  Mid range AP, 2x2:2 MIMO per band that only supports two of the three bands simultaneously.  This AP is ONLY USEFUL in high density scenarios where we would be turning off 2.4 GHz radios anyway on APs.   This AP can be fully powered from a standard PoE+ 30W (802.3at) switch or mid-span injector.  The AP has a single 2.5 Gbps Ethernet port.  (Aruba naming pattern inconsistency:  The Wi-Fi 6 AP-515 was 2x2:2 MIMO on 2.4 GHz and 4x4:4 MIMO on 5 GHz.)

 

• AP-635:  Mid range AP, 2x2:2 MIMO per band, supports operation on all three bands simultaneously.  This is generally the indoor omni AP that should be used for low to moderate density Aruba-based Wi-Fi 6E deployments.  This AP can be fully powered from a standard Class 4 / PoE+ 30W (802.3at) switch or mid-span injector, so long as there is no USB device attached.  Mind your power budgets, however; at a max power of 23.8W, one cannot fully load a standard Class 4 PoE switch.  If you need the USB functionality, a PoE Class 6 (802.3bt) switch (available in the Aruba CX6300 series) or 60W mid-span injector must be used.  The AP has dual 2.5 Gbps Ethernet ports. (Aruba naming pattern inconsistency:  The Wi-Fi 6 AP-535 was 4x4:4 MIMO on both 2.4 GHz and 5 GHz.)

 

• AP-655:  High capacity AP, 4x4:4 MIMO per band, supports operation on all three bands simultaneously.  At a peak power of 51W, a Class 6 PoE (802.3bt) switch must be used.   (The AP will operate as the equivalent of an AP-635 if plugged into a conventional Class 4 / PoE+ switch; if you are not upgrading your switch infrastructure, you are essentially overpaying for an AP-635 by selecting this model).   This AP is primarily appropriate for high density indoor venues, in conjunction with Class 6 PoE switches.  (Aruba naming pattern inconsistency:  The Wi-Fi 6 AP-555 had three radios, and could be operated as 4x4:4 MIMO on 2.4 GHz and 4x4:4 MIMO on two 5 GHz radios, or the two 5 GHz radios could be combined to operate as a single 8x8:8 MIMO 5 GHz radio.)

 

• Ruckus

  Ruckus has publicly declared that they are no longer doing any development of additional Wi-Fi 6E AP models, instead taking the strategy of being early to market in early 2024 with Wi-Fi 7 (802.3be) APs.  Another "high risk-high reward" strategy showing market distinctiveness.  To me, there are still a lot of items to be finalized with Wi-Fi 7, despite the push for initial chipsets, so this strategy seems more risky than Extreme's outdoor Wi-Fi 6E AP, but we shall see.  Time will tell, it always does eventually.
  

 

• R560:  Mid range AP, 2x2:2 MIMO per band, supports operation on all three bands simultaneously.  As with previous Ruckus AP generations, the AP utilizes BeamFlex antenna technology, making it the most suitable for hallway or other “location-constrained” deployments.  This is generally the indoor omni AP that should be used for low to moderate density Ruckus-based Wi-Fi 6E deployments.  This AP can be fully powered from a standard Class 4 / PoE+ 30W (802.3at) switch or mid-span injector, so long as there is no USB device attached or need for the secondary Ethernet port.  Mind your power budgets, however; at a max power of 25.0W, one cannot fully load a standard Class 4 PoE switch.  If you need the USB functionality or secondary port functionality, a PoE Class 6 (802.3bt) switch (available in the Ruckus 8200ZP series) or 60W mid-span injector must be used.   The AP has a primary 5 Gbps Ethernet port and a secondary 1 Gbps Ethernet port.

 

• R760:  High capacity AP, 4x4:4 MIMO per band, supports operation on all three bands simultaneously.  At a peak power of 36.1, a Class 6 PoE (802.3bt) switch must be used.   The AP will operate as a 4x4:4 MIMO AP at lower (but still viable) max power levels of 15 dBm @ both 2.4 GHz and 6 GHz, 16 dBm @ 5 GHz if plugged into a conventional Class 4 / PoE+ switch, along with disabling USB, secondary Ethernet port, and ZigBee/BLE radio.   This AP is primarily appropriate for high density indoor venues.  The AP has a primary 10 Gbps Ethernet port and a secondary 1 Gbps Ethernet port.

 

• Meraki / Cisco
  

  Meraki and Cisco have finally decided to converge on a common hardware platform, though operating with separate firmware to support the very different control platforms.  Given that Cisco acquired Meraki in December 2012 (i.e. over 10 years ago now), this hardware convergence has frankly been long overdue.

 

• CW9162-MR:  Entry-level AP, 2x2:2 MIMO per band, supports operation on all three bands simultaneously.  This is generally the indoor omni AP that should be used for low to moderate density Meraki-based Wi-Fi 6E deployments.  This AP can be fully powered from a standard Class 4 / PoE+ 30W (802.3at) switch or mid-span injector, with the USB port operating at 4.5 W, with a power consumption listed at 30 W (though must actually be <=25.5 W to be compliant with the 802.3at spec as is also stated on the datasheet).  The AP has a single 2.5 Gbps Ethernet port.

 

• CW9164-MR:  Mid range AP, 2x2:2 MIMO on 2.4 GHz, 4x4:4 MIMO on 5 GHz and 6 GHz.  This AP can be fully powered from a standard Class 4 / PoE+ 30W (802.3at) switch or mid-span injector, when the USB port is disabled.  Maximum power is listed at 30.5 W when using an “Ultra PoE” (i.e. Class 6) PoE switch.  The AP has a single 2.5 Gbps Ethernet port.

 

• CW9166-MR:  High end AP, 4x4:4 MIMO on each band.  This AP can be fully powered from a standard Class 4 / PoE+ 30W (802.3at) switch or mid-span injector, when the USB port is disabled.   Maximum power is listed at 30.5 W when using an “Ultra PoE” (i.e. Class 6) PoE switch.   The 2.4 GHz radio can be switched to operate as a second 5 GHz radio.   The AP has a single 5 Gbps Ethernet port.

 

• MR57-HW:  Likely the last of the unique Meraki hardware (and the first Meraki Wi-Fi 6E AP on the market), the specs are similar to the CW9166-HR.  High end AP, 4x4:4 MIMO on each band.  This AP can be fully powered from a standard Class 4 / PoE+ 30W (802.3at) switch or mid-span injector, when the USB port is disabled.   Maximum power is listed at 40 W when using an “Ultra PoE” (i.e. Class 6) PoE switch.  The 2.4 GHz radio can be switched to operate as a second 5 GHz radio.   The AP has dual 5 Gbps Ethernet ports.
  
  

•  Extreme Networks
  

• • AP4000:  Entry to mid-level AP, 2x2:2 MIMO per band, supports operation on all three bands simultaneously.  This is generally the indoor omni AP that should be used for low to moderate density Extreme-based Wi-Fi 6E deployments.  This AP could be fully powered from a standard Class 3/ PoE 15.4W (802.3af) switch or mid-span injector, with the USB port disabled (though Extreme recommends Class 4 / PoE+ 802.3at).  The AP has a primary 2.5 Gbps Ethernet port and a secondary 1 Gbps Ethernet port.
    
    
  •  AP5010:  High end AP, 4x4:4 MIMO on each band.  This AP can be fully powered from a standard Class 4 / PoE+ 30W (802.3at) switch or mid-span injector, when both the USB port and PoE out is disabled.  The 2.4 GHz radio can be switched to operate as a second 5 GHz radio.  The AP has a primary 5 Gbps Ethernet port and a secondary 2.5 Gbps that supports Class 3 / 802.3af PoE out (with Class 6 / 802.3bt input). 
    
    
  • AP5050:  These are the outdoor series of Wi-Fi 6E APs, with the same specs as the AP5010.  The AP comes in two varieties: the AP5050U has an internal omni-directional antenna, and the AP5050D has an internal directional antenna.  As stated above, the 6 GHz radio is currently disabled in the USA until the FCC approves the AFC providers and approves the AP radios.  

 

Staggering 6 GHz Static Wi-Fi Channels

For those like me who like static channel patterns, I decided to codify a set of static channel staggering rules for 6 GHz, both neighboring APs on a floor and “stacked” (or reasonably offset) APs on neighboring floors.  I have established rules for both intra- and inter-floor for indoor 80 MHz, as well as for outdoor (UNII-5 and UNII-7 only) 80 MHz (low density) and 40 MHz (moderate density).  At some point, I will add indoor 40 MHz, and likely outdoor 20 MHz as well.

 

 

 

How practical a static channel plan will be for a 6 GHz outdoor deployment given the nature of AFC is anybody’s guess.  At WLPC2023, I publicly asked Federated Wireless if there are going to be planning tools available, such that Wi-Fi designers can know which specific channels are likely to be “off limits” for a particular geographic coordinates.   If such AFC planning tools could get integrated into Wi-Fi planning software packages like Ekahau, Hamina, and Tamograph (hint, hint), that would be extremely useful indeed to the Wi-Fi community at large.