Wi-Fi 6 Highlights

Jarret B

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Many people may have seen the newer Wi-Fi routers out, which are labeled as Wi-Fi 6. Another label on the router boxes may be 802.11ax. These new router standards are backward compatible with 802.11 b/a/g/n/ac. Let's look at 802.11ax or Wi-Fi 6.

Before we get to Wi-Fi 6 let’s look at the other Wi-Fi generations and see how we got to Wi-Fi 6.

Wi-Fi Generations

Before Wi-Fi 6 there have been six generations of Wi-Fi (no, that is not a typo).

The first generation of Wi-Fi is Wi-Fi 0 or 802.11. The speeds for Wi-Fi 0 were 1-2 Mbps. The standard was technically a Beta version and worked with a radio band of 2.4 GHz.

Wi-Fi 1, or 802.11b, used the 2.4 GHz range at 1-11 Mbps.

802.11a, or Wi-Fi 2, used only the 5GHz band which did not allow it to be backward compatible. It operated at speeds between 6-54 Mbps. This generation showed that the standards needed to be backward compatible since this generation caused so many issues.

Wi-Fi 3 also known as 802.11g used the 2.4 GHz band with speeds ranging from 6-54 Mbps.

Wi-Fi 4 is 802.11n using the 2.4 GHz band at speeds of 72-217 Mbps.

Wi-Fi 5, or 802.11ac uses 2.4 and 5 GHz bands at 433-1733 Mbps speeds.

802.11ax or Wi-Fi 6 has speeds of 600-2401 Mbps.

MIMO

If you look at the bandwidth speeds of the seven generations of Wi-Fi you will notice a big jump occurred at Wi-Fi 5. The jump is partially possible from the 5 GHz band. The band operates at a high frequency, but this is not the main cause of the speed jump.

Multiple In, Multiple Out (MIMO) is a process that uses multiple antennas. You can have two on the transmitting and receiving devices (2x2) or four (4x4).

Let’s look at the bandwidth as being a highway. The highway can have multiple lanes with each lane being a sub-channel. MIMO works like a multi-lane highway going up. If your device is 2x2, then it has two lanes with one above the other. A 4x4 MIMO would be four lanes stacked on top of one another. The multiple ‘layers’ allow for more throughput at the same time.

NOTE: You could think of MIMO as a system with multiple Network Interface Cards (NICs) all connected to the same network at once. You can combine the throughput of each NIC for your total speed.

To determine if your system has MIMO, you must first be using Wi-Fi 5 or 6 with a wireless NIC that also supports 5 or 6. If these are both true then you can issue the commands:

lspci | grep -i wireless - this should result in an output showing the wireless adapter

Output can be similar to:

02:00.0 Network controller: Intel Corporation Dual Band Wireless-AC 3168NGW [Stone Peak] (rev 10)

Use the first set of numbers, in this case ‘2:00.0’ for the next command:

sudo lspci -vv -s 02:00.0 | grep -i "width"

The output could be similar to the following:

LnkCap: Port #0, Speed 2.5GT/s, Width x1, ASPM L1, Exit Latency L0s <4us, L1 <32us
LnkSta: Speed 2.5GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-


From the output, you can see that the width is 'x1' so this wireless device has one antenna and cannot use MIMO.

A Router that supports 4x4 Mu-MIMO can talk to four devices at once. Likewise, a 2x2 Router can talk to two devices at once. If you have more than the specified number of devices, then devices will share. Keep in mind that the Router switches the data stream between two or more devices very fast. It appears to a device that it has a constant connection. The switching is similar to a hard-wired network where only one system can transmit packets on the network at a time. Data speeds can be quite high even though multiple systems are transmitting and receiving at the same time.

NOTE: For MIMO to work the devices and Router must both support MIMO for multiple devices to communicate with the Router simultaneously. Otherwise each device talks to the Router one at a time.

MU-MIMO was introduced in 802.11AC and works very well for allowing sub-channels to communicate with multiple systems at the same time.

Physical Speed

There are many things which attribute to the Physical speed. Of course, the Router speed is important as is the modem speed. Ultimately you could be limited by the bandwidth you are getting from the Internet Service Provider (ISP). For example, if you pay for 1000 Mbps bandwidth and your modem or router only supports 850 Mbps then you are losing 150 Mbps of your bandwidth.

Let’s take an AC2300 device (Wi-Fi 5 or 802.11ac) for example. The speed is listed as 2300, but it is truly 1625+600. This means that the 5 GHz band allows 1625 Mbps while the 2.4 GHz band supports up to 600 Mbps. Together the throughput is 2225 Mbps which is rounded up to 2300.

Let’s look at the specs on the Asus AX6000 router. The router is tri-band, which means there are three antennas. The three bands are for 2.4 GHZ (AC speed of 4333 Mbps), 2.4 GHz (AX speed of 1148 Mbps) and 5 GHz (AX speed of 4804 Mbps). The total speed is 5952 for the AX bands. There is an extra 4333 Mbps for the AC band for backward compatibility. Each of the AX bands supports MIMO of 4x4.

The throughput is not actual for the speeds given. Keep in mind that TCP/IP has a lot of overhead in the packets. Each packet will of course contain the data payload. More than likely the data payload will require numerous packets to hold all of the data. The packets are a set size and in most cases are smaller than the data being sent. Each packet must be received at the receiving end system and the data removed from the packets and put back together. Each packet contains a lot of information other than the data itself. There is included the IP Address, MAC Address, routing information, packet number and quite a bit more information in the packet. You may be sending packets at a speed of 4804 Mbps on a 5 GHz band to the AX6000 router, bit the actual amount of data being sent is quite a bit less. People may be looking at sending a file to the Internet which is 1 GB in size. You perform a speed test and find that you get a reported speed of 4500 Mbps. Since the speed is in megabits (Mb) you need to divide by eight to find the speed in megabytes (MB). A speed of 4500 Mbps is about 562 Mbps. The speed shows that the file should take about 1.8 seconds to send if the speed is constant. In reality with the overhead, you could be talking over 10 seconds (or longer).

With TCP/IP transmissions there is also the fact that after so many packets the sending system waits to hear from the receiving system. The receiving system needs to verify that the packets were all received. If any packets were lost the receiving system notifies the sending system which then re-transmits the necessary packets. These pauses, though very slight, still slow down the total transmission times.

Mesh Networking

Mesh networks are just another way to say a network made up of several routers. All routers act as one network with one name. You can have multiple routers creating a network, but each one is its own network with a different Service Set Identifier (SSID). If all routers have the same SSID and create one network then the routers create a Mesh network. For example, in a large building such as a department store, there will be multiple routers. As you walk around the store your phone will connect from one router to another. The concept is the same as your phone changing cell towers as you drive around and talk. You do not need to open your Wi-Fi app and reconnect to a different SSID. As you move, your phone will change automatically since you already connected to one of the routers in the Mesh.

The initial router will be connected to the modem to allow transmission to the internet. Other routers in the mesh will be plugged in for power but be in the range of the first (main) router. The other routers will transmit and receive data from the main router which is like the gateway.

Channel Bonding

The 5GHz band allows for 500 MHz channels.

If we set the channels to be 20 MHz each, we can have 25 channels (20 x 25 = 500). If the channels are 40 MHz then there can be 12 channels. Channels can go up to 160 MHz each, but only allowing for 2 channels.

The physical components of the router can limit the number of channels and the channel width. The more width there is, the more data can be sent through the channel. The problem is that the fewer channels there are will limit the number of devices that can be communicated with at once. With Wi-Fi 5 (802.11AC) you can talk with 25 devices at once if you use a 25 MHz channel. Of course, the devices need to support MU-MIMO as well.

Be sure you check your devices as explained previously in this article, otherwise, you can only use one channel.

If you have a Wi-Fi device that uses a standard before 802.11AC (Wi-Fi 5) then that device will use all channels since it can only use the whole band at once. This is why you need to make sure all devices are on the same standard to benefit from all of the abilities of a specific standard.

802.11AX (Wi-Fi 6)

Now that we covered a lot of Wi-Fi terminology we can look at Wi-Fi 6.

Wi-Fi 6 allows for multiple devices to share a single channel. If you have multiple IoT devices which each need 1 MHz of space then you could have 20 IoT devices share a single 20 MHz channel.

A smartphone may need to use 5 MHz to update an app as you are in a store. With a 20 MHz channel, there can be four people sharing a channel.

On a social network, such as a department store, the benefits of Wi-Fi 6 will greatly improve performance for multiple users.

In a home environment of a small number of devices, Wi-Fi 6 may not improve throughput to devices. Most people using Wi-Fi 5 in a home environment are not having major issues. Most issues in homes are related to interference with other nearby routers.

There are many other aspects of Wi-Fi 6 which do improve its capabilities, but mostly these are all for areas of a high number of devices.

Conclusion

The main aspect is that the 802.11AX standard is not to be finalized until later in 2020. Until this occurs, changes may be made (you never know).

Any 802.11AX routers will not give you the full functionality of new features unless your devices support 802.11AX as well. Be aware of the fact that your devices need to compatible. Don’t go buy a newer router and expect it to outperform your existing router. There are very many components to make everything work well. If all your systems are still using 802.11AC then you should still have the same performance (maybe).
 
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Jarret B

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I am sorry, but I would have no idea. If you do not need to connect a lot of multiple devices at once (like in a public place), then stick with WiFi 5. The technology works just fine. If you need good WiFi speed then look for a high end router and high end dongles (large download numbers). I found an AC 2300(?) and it gets great coverage and decent speeds. For devices which need absolute high speeds you can direct connect it. My two sons each have an xbox that I hardwired to the router to get twice the speed as a WiFi connection.
 

min

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Hi Jarret,

Thank you for the great insights. I'm just really curious and researching about this new wifi tech and found your post.

I'm abit confused because the manufacturer told in the product's datasheet that the wireless card in my computer is a dual band card but after follow your instruction, i find out that it is not. But I physically can see that it has 2 antennas.

21:00.0 Network controller: Intel Corporation Wireless-AC 9260 (rev 29)
LnkCap: Port #0, Speed 5GT/s, Width x1, ASPM L1, Exit Latency L1 <8us
LnkSta: Speed 5GT/s (ok), Width x1 (ok)


Another thing i don't understand is if Wifi 6 is still a draft standard, then why some manufacturers have already released their Wifi 6 routers and network cards? Are they compatible regardless of manufacturers?
 

Jarret B

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Some manufacturers do release a product before the standard is set. Of course, they want to be the first or one of the first to release the new technology.
Compatibility? At this point, who knows? You would definitely think so, but in the past, we have seen this issue before. Not everything is always compatible across manufacturers.
The antenna issue could be a driver issue. Maybe it's not reporting back to the system properly, or it isn't initializing both antennae. If the router is not Wifi 6, then it will not initialize both antennae.
 


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