Wi-Fi 6 also known as 802.11ax is the latest generation of 802.11 WiFi standard and the successor of Wi-Fi 5 aka 802.11ac.
Wi-Fi 6 increases user throughput by more efficient spectrum usage, provides larger signal coverage and reduces the power consumption.
In the following section, we will discuss the significant improvements of Wi-Fi 6 over Wi-Fi 5 and summarize their differences.
Wi-Fi 6 or 802.11ax?
It is the same thing. WiFi-6 is just more customer-friendly name for 802.11ax standard introduced by Wi-Fi alliance [1]. Replacing 802.XX with a simple numerical suffix helps users easily distinguish between the different Wi-Fi standards.
Table 1 summarizes new naming convention for Wi-Fi standards.
How fast is Wi-Fi 6
W-Fi 6 provides data rates up to 9.6Gbps, while Wi-Fi 5 only up to 6.9Gbps [2]. Wi-Fi 6 is about 30% faster than Wi-Fi 5.
Why is Wi-Fi 6 faster
In general, the faster Wi-Fi 5 rates are accomplished by using faster modulation and coding schemes, wider channels, and adoption of Multiple Input Multiple Output (MIMO) technologies [3].
Wi-Fi 6 also employs a new channel access approach that allows multiple clients to work smoothly on the same network at the same time. To do so, Wi-Fi 6 uses OFDMA and bi-directional MU-MIMO.
Both technologies significantly improve overall wireless network performance in dense environments, such as stadiums, airports, and so on.
Orthogonal Frequency Division Multiple Access (OFDMA)
OFDMA enables 802.11ax access point (AP) to communicate simultaneously with multiple stations dividing Wi-Fi channels into smaller sub-channels – Resource Units (RU).
Each RU may be utilized by different clients that are serviced simultaneously. As a result, a single device does not need to wait for AP to serves data. Instead, smaller data packets are transferred within multiple RUs. Data rates increase and latency is reduced by 75%. [4]
If we think a wireless connection as a series of trucks delivering data within packets (trucks), the 802.11ac standard allows only one delivery inside a truck to be delivered to a single device at time. However, OFMDA, divides each truck into different RUs that transmit multiple deliveries to multiple devices at a time.
Bi-directional Multi-User MIMO
Unlike, OFDMA where devices are partioned into different RUs, with MU-MIMO devices are partioned into different spatial streams.
Down-link (DL) MU-MIMO available in 802.11ac allows wireless network to increase its performance transmitting to multiple clients in the downstream direction from AP to clients.
The 802.11ax goes further and implements Bi-directional 8x8 Multi-User MIMO. supporting transmission up to eight devices at a time in both upload and download direction.
Analogous to our previous example, eight trucks can deliver to eight locations at the same time.
BSS Coloring
It is Wifi-6 feature which improves network congestion by identifying overlapping Basic Service Sets (OBSS).
In general, if there is a different color in the frame header, the device ignores it and continues the transmission. If not, it is an intra-BSS transmission and the frame is processed.
Wi-Fi 6 / Wi-Fi 6E Frequency Band and Channel Width
The wider the Wi-Fi channel, the more data can be transferred over it and the faster the wireless connection.
Both WiFi-6 and WiFi-5 standards support up to 160MHz channel width. Prior to configuration of the channel width on a router, frequency range of the Wi-Fi band (2.4/5GHZ/6GHz) must be taken in the account (Table 2).
The smaller the frequency range of the band and the greater the interference from other Wi-Fi networks, the smaller the channel width we choose.
Wi-Fi 5 alias 802.11ac uses 5GHz band only, while Wi-Fi 6 (802.11ax) can operate on both 2.4GHz and 5GHz bands. Wi-Fi 6E adds support for 6GHZ band.
While in 5GHZ band, Wi-Fi 6 router can be configured to use a single non-overlapping 160MHz channel, (typically between 20/40/80MHz), Wi-Fi 6E can benefit from additional frequency range 1200MHz in 6GHz band and creates seven more 160MHz channels. [5][6]
Wi-Fi 6 Signal Coverage
The higher Wi-Fi frequency, the shorter the radio wavelength.
When it comes to WiFi signal coverage, the higher the radio frequency of the WiFi transmitter, the smaller geographical area covered. This is due to a fact that the shorter radio wave penetrates solid objects worse. [7]
Wi-Fi 5 works only on the 5GHz band. Wi-Fi 6 is dual-band 2.4 and 5 GHz technology so the area covered by WiFi signal in 2.4GHz band is larger as the signal propagates further.
Transmitting power can be then reduced which in turn saves a battery life. The battery life is one of the biggest hurdles for IoT. For Wi-Fi IoT devices, 2.4GHz band will be very likely a band of choice.
Wi-Fi 6 Power Consumption
Wi-Fi 6 employs Target Wake Time (TWT) which allows devices to negotiate when and how often they will wake up to receive and send data.
Before 802.11x clients would sleep for some milliseconds and then wake up, exchange data and go back to sleep. With TWT. clients may sleep for seconds, minutes or even hours. [8]
TWT mechanism extends the sleep time, so power consumption is reduced and battery life is significantly improved.
Wi-Fi 6 Compatibility with Wi-Fi 5
Wi-Fi 6 devices is supposed to be backwards compatible with previous generations of Wi-Fi. Therefore, they should support 802.11a, b, g, n and ac standards.
Most all of your wireless clients will work with the new Wi-Fi 6 router, and vice versa. For instance, your new cutting-edge Wi-Fi 6 Samsung Galaxy Z Fold3 5G smartphone will work with the legacy Wi-Fi 3 router.
Final World
Wi-Fi 6 clients and routers will become increasingly available and will gradually replace older WiFi devices. You do not need to replace your Wi-Fi 5 router right now, but if you plan to change it, buy the one that supports Wi-Fi 6.
With the growing number of IoT devices in homes, bandwidth-hungry applications such as 4K video, the Wi-Fi 6 router will become inevitable choice and a good investment that provides a better user experience.