Cambium Networks XV2-2 data sheet

Cambium Networks, Inc 802.11ax white paper Page 1 of 12

2020 vision on 802.11ax

Abstract

802.11ac shows us how fast the network can be. 802.11ax will show us how to maximize all the available
spectrum in the 2.4GHz and 5GHz ISM and UNII bands. 802.11ax will focus on improving the connected
client experience by making the network more efficient.

Client and standards ecosystem support for 802.11ax is expected in the year 2020. With a clear view of
this new technology, network architects will design the decade of the 2020s using 802.11ax. This paper
discusses how 802.11ax will address the changing needs of Wi-Fi networks.

Daran Hermans, Product Management
Cambium Networks
2590 North First Street, suite 220. San Jose CA 95519
[phone]

Cambium Networks, Inc 802.11ax white paper Page 2 of 12

More streaming content, More devices

By 2021, streaming video over the Internet will be
82% of all Internet traffic. In terms of bytes
transmitted, this represents a 70% increase over

2016.

Streaming video will not be limited to primetime
in North America; it is global, all day, all the time.
Live video, primarily sports but also news
programs, will increase by 95% in the same time.
And the quality of video in 2020 will also
dramatically increase as more content providers
push out 8k video.

Combined, hotels represent the largest “public access networks” in the world. No matter where you travel,

you can find a hotel that offers free guest Internet access. Today hotel service providers report an average
of 2.75 devices per guest, with 95% of guest devices being a smart phone or tablet. Streaming media is the
number one application in total bitrate consumed by guests. Enterprise All Wireless Office, BYOD and
online education are also driving higher device density year over year, and higher bitrates.

Voice over Wi-Fi calling offers tremendous advantages and cost savings to the client and the carrier. Calls
can be placed and received using the phone dialer, not a separate app. Indoor cellular coverage issues go
away, as the phone need only connect to a local 802.11 access point. Voice calls take less than 100kbps for
the encapsulated voice packets and overhead. Yet, due to the way 802.11 OFDM operates, a small voice
packet consumes one transmission opportunity (TxOP) and the full 20 MHz wide channel.

IOT devices are always-on, always-connected and wireless. In consumer and enterprise markets, IOT
devices provide environmental monitoring, lighting and HVAC control, access control, motion alerts and
more. As with the voice packets, IOT messages are small data exchanges between the IOT device and the
application server. Today, many IOT devices run a custom MAC based on 802.15.4 (aka Zigbee). in the
2020s, low cost 802.11 radios and the concept of running everything in a single access domain may drive
significant interest in the use of 802.11 radios for IOT devices.

Cambium Networks, Inc 802.11ax white paper Page 3 of 12

802.11 networks get faster

802.11n was introduced in 2009; about the same time when smart phone
sales were exploding, and tablets were introduced. Since early generation
smart phones and tablets had a single antenna element, 802.11n provided a
practical limit of 72 Mbps RF rate on a single 20 Mhz wide channel. When
network packet overhead and half duplex transmission is factored in, the
effective bitrate of the 802.11n networks is about 35Mbps.

802.11n cannot keep up with the device density and high bitrate changes
experienced today.

802.11ac introduced in 2013 builds on several
successful technologies from 802.11n. Notably,

802.11ac allows wider channel bonding up to a
practical limit of 80 MHz, airtime fairness and
standardized beam-forming. Also,

802.11ac wave 2 technology
introduced multi-user MIMO (DL
MU-MIMO) capability to help bridge
the gap between the access point
capability and the client device
capability. Access points are
physically larger, support more
antennas, are plugged into the AC
mains for continuous power, and include high performance CPUs and DRAM. Client devices are designed
for great cameras and screens, but do not have the CPU processing power to use mulitple streams and do
not have space for optimal antenna design. Thus, MU-MIMO allows the access point to transmit
concurrently to more than one client at a time. In 802.11ac, MU-MIMO is limited to downstream packet
only, thus it is often written as DL MU-MIMO.

Speed = Capacity

A typical 802.11ac client device will support up to 80 MHz channel width and two spatial streams. This
could be a tablet, or any top tier popular smart phone. With this configuration, the RF PHY rate will be 867
Mbps. A faster RF PHY rate leads to more contention-free time for other devices to access the RF medium,
lower RF noise, and higher capacity.

The decade of the 2020s will bring widespread use of IOT devices in every home and enterprise and more
personal devices. Additionally, 8k video will become commonplace and streaming media bitrates will rise
again.

A new generation of Wi-Fi technology will be needed.

Cambium Networks, Inc 802.11ax white paper Page 4 of 12

Higher channel efficiency

Whereas 802.11ac made the network faster, 802.11ax is designed for
higher channel efficiency in a dense networking environment. The key
technology behind 802.11ax, multiple access OFDMA, comes from the
3GPP LTE cellular technology and 802.16e WiMax. OFDMA, orthogonal
frequency division multiple access, is a field proven technology to
support higher density wireless networks.

802.11ax anticipates higher density in several ways; scheduled transmission time, dynamic frequency
allocation in 2 MHz increments, spatial reuse and improved battery management mechanisms.

OFDMA enables efficient spectrum use

802.11a, 802.11g, 802.11n and 802.11ac use OFDM (orthogonal frequency division multiplexing). OFDM
was a significant enhancement over 802.11b DSSS. OFDM splits the signal over multiple narrow band
carriers. This results in reduced crosstalk interference and allowed higher RF rates.

In an 802.11ac network with OFDM, the
smallest frequency unit assigned to a
transmission is 20 Mhz. The entire 20 Mhz
frequency is used to transmit to and from any
single client device. If that device is sending a
small 64 Byte IOT packet or a 1248 Byte video
packet, it uses the same 20 Mhz. (the author
acknowledges that narrowband industrial and
IOT applications using 802.11 can be purpose
built to use 5 MHz or 10 Mhz frequencies.
This is not equivalent to OFDMA sub­channels).

OFDMA divides up the 20 MHz channel into 256 subcarriers. The smallest unit is 26 subcarriers in 2 Mhz of
frequency. These subcarriers can be grouped together into larger units; at 52 (4 Mhz), 106 (8 Mhz), and
242 (20 Mhz) to support higher bandwidth applications. Each grouping of subcarriers are called a resource
unit (RU).

Any single client device is assigned one or more RU. Each RU can be transmitted at a unique QAM level.
Additionally, as the client device moves farther away from the access point, the number of RU and the
QAM level can be adjusted to maintain a strong signal level even as throughput degrades. Dynamic RU
allocation is a direct benefit of OFDMA use in LTE networks.

802.11ax is about
efficient use of RF

spectrum to

increase network

capacity