With an 801.11ax WLAN, how many simultaneous connections could be made using 160Mhz wide channels?

  • Do you mean how many channels there are in total, how many can be aggregated in a connection or how many users can use each simultaneously? – Zac67 May 23 '20 at 10:28
  • I mean how many client devices could connect at 160mhz simultaneously – exharris May 23 '20 at 10:35
  • "I mean how many client devices could connect at 160mhz simultaneously" There is a practical limit of how may users can connect on one channel. Even with the old 802.11b, many users could connect to a channel, but the more users on the channel, the worse the performance. It really boils down to what you consider acceptable performance. – Ron Maupin May 23 '20 at 14:10
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    "connect at 160 MHz simultaneously" - as in associate with the WAP or actively transmit/receive data? – Zac67 May 23 '20 at 22:07
  • My AX AP doesn’t seem to allow two ax clients to connect to a 160mhz band. It only allocated to 80mhz bands unless I amend settings to force 160 and even then only the first AX client connecting gets 160Mhz.. the second one always goes on 80. – exharris May 24 '20 at 10:37

The question posed is ill defined in some ways. We assume it is referring to one AP (if it is referring to more than one AP, then additional questions arise regarding the layout, etc., and interference between APs comes into the picture).

802.11ax, also known as High Efficiency Wireless, is designed to attack the problem of dense deployment scenarios, i.e., to be more efficient when there are many users attempting to use the same 802.11ax WiFi system. Correspondingly, the target is an increase by a factor of 4, of the average throughput per user in high-density scenarios, such as at train stations, airports and stadiums.

802.11ax is the first family member of 802.11 that supports OFDMA. In earlier generations of Wi-Fi, even up to 802.11ac, channels could not be shared. With 802.11ax, OFDMA is introduced, allowing multiple STAs to share the same 160 MHz channel (or other channel bandwidths also, but since you asked about 160 MHz, that's what we focus on for now). Different sizes may be used for the Resource Units (RUs). The smallest RUs have just 26 subcarriers. In that case, if all STAs are assigned these smallest RUs, a 160 MHz channel can be shared by 74 users. See https://www.ni.com/en-sg/innovations/white-papers/16/introduction-to-802-11ax-high-efficiency-wireless.html for more details.

ps. to be more accurate, there is already some of this kind of simultaneous radio resource sharing in the AP-to-STA direction only even in 802.11ac, but 802.11ax goes further, including support in STA-to-AP as well.

  • You can have many more simultaneous connections on a channel than users simultaneously sharing the channel. I think that is what the OP's comment clarifies. – Ron Maupin May 23 '20 at 18:05
  • I don't think the OP clarified that. It was too ambiguous.But if you're referring to "simultaneous connections" as the sharing of the same channel that is implemented with the MAC layer features like clear channel assessment before transmissions, then, yes. As more and more users join this way, signal quality goes down, their data rates go down, etc. – auspicious99 May 24 '20 at 3:13
  • But since the OP was asking about 802.11ax, I think it is reasonable to point out the OFDMA related dimension of channel sharing that in this other sense supports multiple "simultaneous connections". – auspicious99 May 24 '20 at 3:15
  • I think my query was based on an incorrect assumption that only one client could be connected to a 160Mhz band at a time (regardless of usage/throughput) – exharris May 24 '20 at 10:36
  • @exharris Previously, although multiple clients could be connected simultaneously, they'd be time sharing the usage of the medium in a way which leads to a less efficient utilisation of the radio resources than could be achieved with 802.11ax. – auspicious99 May 24 '20 at 13:42

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