I have a Netgear Wi-Fi extender EX3700 AC750 (300 Mbps in 2.4 GHz, 433 Mbps in 5 GHz) that can connect to the Wi-Fi main router at 433 Mbps on the 5 GHz band (the configuration page doesn't display the channel width of this connection). This extender uses 2 antennas. The extended 5 GHz network I set up uses a different SSID, on channel 42, and has a channel width of 80 MHz using this channel set: 36(primary)+40+44+48 (this is default, no options to select a channel width).
I'm considering the FebSmart Wi-Fi PCIe card FS-AC87 AC1200, that uses 2 antennas, with a maximum connection speed of 867 Mbps on 5 GHz, 80 MHz wireless networks (on 2.4 GHz its maximum connection speed is 300 Mbps).
And, looking at the TP-Link RE450 Wi-Fi extender AC1750 that uses 3 antennas (I suppose it broadcasts 3 spatial streams). This extender has a maximum connection rate of 450 Mbps in 2.4 GHz, and 1300 Mbps in 5 GHz.
As I understand on 2.4 GHz networks, 1 stream has a maximum connection speed of 150 Mbps and channel width of 20 MHz.
My question is on 5 GHz networks, does each stream have a max connection speed of 433 Mbps, and a max channel width of 40 MHz? And, are some low-end devices only capable of a lower connection speed of 216 Mbps on each stream (2 streams at 433 Mbps), and lower channel width on each stream (probably 20 MHz) even on a 5 GHz network, such as the case of my Netgear Wi-Fi extender?
1 Answer
Your question sounds like you might have some misconceptions, so first here's some background on 5 GHz Wi-Fi operation over the last 3 major generations of the technology, and then I'll give specific answers to your questions at the bottom.
N (also known as "Wi-Fi 4"), uses either the 2.4 GHz or 5 GHz band, supports 1-4 spatial streams, and 20 or 40* MHz-wide channels, although support for 4 spatial streams never shipped before AC came out.
Top signaling rate per spatial stream is as follows:
| Channel width (MHz) | Max PHY rate per spatial stream (Mbps) |
|---|---|
| 20 | 72 |
| 40 | 150 |
*Note that although N and AX support 40 MHz-wide channels in 2.4 GHz, it's generally considered a poor choice to use anything other than 20 MHz-wide channels in the crowded 2.4 GHz band, especially if you want Bluetooth, which also uses the crowded 2.4 GHz band, to work.
AC (also known as "Wi-Fi 5"), uses the 5 GHz band only*, supports 1-8 spatial streams, and 20, 40, 80, or 160 MHz-wide channels, although support for more than 3 spatial streams or 160 MHz-wide channels has been pretty rare.
Top signaling rate per stream is as follows:
| Channel width (MHz) | Max PHY rate per spatial stream (Mbps) |
|---|---|
| 20 | 87 (1-2 SS) or 96 (3+ SS) |
| 40 | 200 |
| 80 | 433 |
| 160 | 867 |
*Note that even though AC is 5GHz-only, all equipment that supports AC also supports N for 2.4 GHz operation. Some chipset vendors even do nonstandard proprietary tricks to do AC-like signaling in the 2.4 GHz band, but again, that's nonstandard. (e.g. Broadcom TurboQAM)
AX (also known as "Wi-Fi 6") uses either the 2.4 GHz or 5 GHz band, supports up to 8 spatial streams (but again, support for more than 3 spatial streams is rare, especially among client devices), and supports 20 and 40* MHz-wide channels in either band, plus 80 or 160 MHz-wide channels in the 5GHz band. Support for 160 MHz-wide channels is pretty common (but not guaranteed) among AX equipment.
Top signaling rate per stream is as follows:
| Channel width (MHz) | Max PHY rate per spatial stream (Mbps) |
|---|---|
| 20 | 143 |
| 40 | 287 |
| 80 | 600 |
| 160 | 1201 |
*Once again note that it's widely considered best practice to limit your 2.4 GHz band's channel width to 20 MHz to leave room for Bluetooth and other uses of the band.
So to answer your particular questions:
As I understand on 2.4 GHz networks, 1 stream has a maximum connection speed of 150 Mbps and channel width of 20 MHz.
No. Here's the full list of max PHY rates by technology and channel width in 2.4GHz:
802.11-1997 DSSS: 22 MHz-wide channels, 2 Mbps max PHY rate. B: 22 MHz-wide channels, 11 Mbps max PHY rate. G: 20 MHz-wide channels, 54 Mbps max PHY rate. N: 20 MHz-wide channels: 72 Mbps max PHY rate per spatial stream. 40 MHz-wide channels: 150 Mbps max PHY rate per spatial stream. AC: Not Applicable. AC does not operate in 2.4 GHz. AX: 20 MHz-wide channels: 143 Mbps max PHY rate per spatial stream. 40 MHz-wide channels: 287 Mbps max PHY rate per spatial stream.
My question is, on 5 GHz networks, does each stream have a max connection speed of 433 Mbps, and a max channel width of 40 MHz?
Close but not quite.
First, "…on 5 GHz networks…" isn't enough information. We need to know if we're talking about N, AC, or AX.
For N, each spatial stream has a max PHY rate of 150 Mbps when used with 40 MHz-wide channels, which is typical of N usage in 5 GHz. When limited to 20 MHz-wide channels, each spatial stream is limited to 72 Mbps.
For AC, which is only in 5 GHz, each spatial stream has a max PHY rate of 433 Mbps when used with 80 MHz-wide channels, which is typical of AC usage in 5 GHz. But for AC with full 160 MHz-wide channels, each spatial stream would have a max PHY rate of 867 Mbps. With 40 MHz-wide channels, the max PHY rate per spatial stream is 200 Mbps. With 20 MHz-wide channels, the max PHY rate per spatial stream is 87 Mbps if you only have 1-2 spatial streams, but goes up to 96 Mbps if you have 3+ spatial streams.
And, are some low-end devices only capable of the lower connection speed 216 Mbps on each stream (2 streams at 433 MHz), and lower bandwidth on each stream (probably 20 MHz) even on a 5 GHz network, such as the case of my Netgear Wi-Fi extender.
I've never seen an AC-capable device that was not capable of 80 MHz-wide channels. So almost all AC-capable devices are capable of the 433 Mbps PHY rate under good RF conditions (high signal, low noise).
Your Netgear EX3700 extender has two antennas, and it supports 2x2:2 MIMO (2 spatial streams) in N operation, but in AC operation it only supports a single spatial stream, which is why its max AC PHY rate is 433 Mbps (1 spatial stream, 80 MHz-wide channel).
3
