a manufacturer of RF and microwave filters, has published a special newsletter for the
end of the year. In it, Sam Benzacar talks about all the good stuff in the queue for
WiFi in 2018. There can be no doubt that the number of WiFi-connected devices in the
average home (10, per Sam's letter) is growing at a rapid rate.
Echos (Alexa AI),
smart AC receptacles,
WiFi-controlled light bulbs, among many others. IEEE 802.11ax is
providing 1024QAM modulation at 9607 Mb/s data with multi-user MIMO (MU-MIMO). As has
been the trend with all electronics, features and performance goes up while prices come
down. It's a brave new world.
A Word from Sam Benzacar
Help Is Coming
for Wi-Fi in 2018
By Sam Benzacar
Next to cellular service, Wi-Fi is the undisputed champion of wireless services. It's
so well suited for so many applications that in crowded places like airports, convention
centers, and stadiums, it can be tough to connect or maintain a connection (Figure 1).
Depending on the source you choose to believe, the average home has 10 Wi-Fi-enabled
devices, and if it includes gamers and binge-watchers along with the usual smartphones
and tablets, it's possible to max-out a legacy (i.e., 802.11b) access point that has
only channels in the 2.4 GHz band at its disposal.
The ability of 802.11n and ac to use 5 GHz channels along with features like MIMO
provides massive improvements, but it's likely even this won't be enough in the coming
years. All of this hasn't been lost on the Wi-Fi Alliance and Wi-Fi chipset and equipment
manufacturers, and help is on the way in the form of 802.11ax, most likely in a few months.
When developing the standard, the primary focus was on addressing the issue of congestion
rather than simply increasing speed. In fact, 802.11ax is only about 37% faster than
802.11ac but it builds on the "best" of its predecessor and add a long list of other
tweaks, some for the first time in Wi-Fi.
A typical 2.4 GHz Wi-Fi signal environment (and far from the worst)
shows the challenge for an access point
The list in Table 1 covers some but far from all of the differences between 802.11ax
and 802.11ac, but they're the top tier. 802.11n, which preceded 802.11ac, uses both 2.4
GHz and 5 GHz channels, but 802.11ac uses only those at 5 GHz, so a leapfrogging of sorts
has been taking place, as 802.11ax also uses both frequencies. It also offers channels
up to 160 MHz like 802.11ac but significantly increases capacity but upping the modulation
rate to 1024QAM, a first for W-Fi.
Differences in data rates between the two are self-explanatory, and it's probably
obvious that no one is likely to be experiencing a download rate of 9.6 Gb/s any time
soon as Wi-Fi speed can only be as high as its source, typically broadband, and few people
have anything close to even 1 Gb/s. That said, when 10 Gb/s becomes available 802.11ax
will be ready. The widely quoted benchmark goal for 802.11ax is to deliver a four-times
improvement in throughput and quality of service versus 802.11ac. It aims to deliver
this indoors and outdoors and even in dense signal environments. Range is about the same
Table 1 –802.1ax Versus 802.11a
In addition to the above, the major improvement in the new standard come from the
- Orthogonal Frequency Division Multiple Access (OFDMA) modulation: Standards beginning
with 802.11g use Orthogonal Frequency-division Multiplexing (OFDM) and as OFDMA lets
multiple devices occupy the same channel, it increases spectral efficiency through better
scheduling of devices to avoid "collisions" between them.
- Target Wake Time (TWT): This new feature, at least for Wi-Fi, reduces device power
consumption using precise synchronization algorithms so that a device is only fully awake
when it needs to communicate with the access point.
- Multi-User MIMO: Wi-Fi has availed itself of MIMO's benefits for some time. MU-MIMO
is a lot more sophisticated as rather than being able to access a single device at one
time, an access point can handle several while modifying the antenna pattern through
beamforming (Figure 2) to dedicate the most resources to the user devices that needed
it most. 802.11ac does this in the downlink path only; 802.11ax adds the uplink path
- Basic Service Set (BSS) coloring: A BSS is the term used to describe a Wi-Fi access
point and all the devices that are connected to it. 802.11ax using a technique called
"BSS coloring" to reduce co-channel interference. This should be a benefit in dense signal
environments as it makes the reuse of channels more efficient.
Single-user MIMO (left) sends its signal to every device. Multi-user
MIMO (right) forms beams (like phased-array radar) to active devices, dramatically increasing
performance and potentially, range.
These enhancements and others collectively make 802.11ax a huge leap forward for Wi-Fi,
and ought to improve overall quality of service everywhere, not just in the most challenging
places it's targeted for. Of course, getting all of the benefits from 802.11ax requires
a new access point (router) and an 802.11ax-enabled user device. The first such smartphones
are likely to appear when the major players, primarily Samsung and Apple, introduce their
next products in the fall. TVs and streaming devices could take longer, and public hotspots
are likely to be last.
Check out Our Filter Products
Band Pass Filters
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About Anatech Electronics
Anatech Electronics, Inc. (AEI) specializes in the design and manufacture of standard
and custom RF and microwave filters and other passive components and subsystems employed
in commercial, industrial, and aerospace and applications. Products are available from
an operating frequency range of 10 kHz to 30 GHz and include cavity, ceramic, crystal,
LC, and surface acoustic wave (SAW), as well as power combiners/dividers, duplexers and
diplexers, directional couplers, terminations, attenuators, circulators, EMI filters,
and lightning arrestors. The company's custom products and capabilities are available
Anatech Electronics, Inc.
70 Outwater Lane
Garfield, NJ 07026
Posted December 29, 2017