This short video presents an overview of 802.11be modeling
in MATLAB with Wireless LAN Toolbox.
Wireless LAN Toolbox supports physical layer and MAC
and system-level modeling of the IEEE 802.11
series of standards.
At the physical layer, you find models
for transmitter, propagation channel, and receiver.
The typical measurements of interest
are packet error rate and EVM.
At the MAC and system-level, it introduces MAC frames
with detailed headers, and scheduling concepts
such as RTS/CDS and EDCA, along with the ability
to look at throughput and latency
due to channel contention in the presence of multiple stations.
As of release 2021b, the latest additions to the standards
supported by Wireless LAN Toolbox are 802.11ba
for wake-up radio, 802.11az for positioning,
and 802.11be also known as WiFi-7,
for extremely high throughput.
This video focuses on 802.11be.
Wireless LAN Toolbox, release 2021b supports draft 1.0
of the 802.11be standard, and we actively update the Toolbox
as the standard matures.
It supports most Release-1 features,
including 4,096-QAM modulation, increased bandwidth of 320
megahertz--
both of which increase the maximum possible data rate that
802.11be offers--
EHT multi-user packet format generation and decoding,
with multiple resource unit assignment and preamble
puncturing, and phase rotation for the 320 megahertz preamble.
Generating 802.11be waveforms with Wireless LAN Toolbox is
very similar to any other standard and happens in two
steps.
Step one-- specify the 802.11be configuration.
Step two-- invoke the waveform generator.
This slide shows a simple example code to do so.
You select the channel bandwidth and then,
for any user, the desired MCS.
Here we select 12, which corresponds to 4,096-QAM with
a 3/4 coding rate.
The last line generates the waveform.
Increased bandwidth and higher order modulation are but two
aspects of the exciting new features in the 802.11be
standard.
Improvements in resource allocation,
such as multiple resource units, and additional flexibility
in channel puncturing are also of great interest,
and they are shown in detail in the waveform generation example
that ships with Wireless LAN Toolbox.
Here is a look at this example in MATLAB.
It shows many different possible configurations
for waveform generation, as shown in the table of content.
Let us look at two of these configurations.
First, punctured package generation with large MRU
for multiple users.
We set up a multi-user MIMO 320 megahertz configuration
for two users, with puncturing field value 3.
This puncturing value of 3 indicates
that we are puncturing the third 40 megahertz
channel, as shown here.
As a result, the overall assignment
shows users one and two assigned throughout the 320 megahertz,
with one 40 megahertz channel punctured.
Then, let's look at preamble puncturing
for OFDMA transmission.
You can see that the requested configuration
uses two allocation indexes--
64 and 26-- to characterize eight RUs.
Those indexes are defined in the standard.
26 represent a punctured 242 tone RU,
while 64 represents a single-user 20 megahertz
channel.
Therefore, that configuration represents an assignment
to five different users occupying 20 megahertz
each, with RUs 2, 6, and 7 punctured.
When you generate the waveform, you
can clearly see that those three areas are punctured,
both preamble and data.
Once you have generated a 802.11be waveform,
you can build an end-to-end example,
using a propagation channel and receiver.
Wireless LAN Toolbox includes different types
of Wireless LAN specific propagation channels,
including the TGax channel.
The TGax channel lets you configure many different types
of impairments, with fading line-of-sight
or non-line-of-sight conditions, depending on the transmit
receive distance, antenna configuration,
and propagation conditions, such as shadowing and path loss.
It was updated to support 328 megahertz bandwidth.
You can also find many other types
of impairments and channels in Communications Toolbox,
including ray-tracing channels, phase noise,
and nonlinearities.
Once you have a waveform and simulated
the impact of propagation, you can set out
to determine the overall performance of the link
at the output of the receiver.
This is what the example shown here does.
The receiver detects packets and processes legacy,
and then EHT specific fields, before demodulating,
equalizing, and decoding EHT data.
Let me point out that you have full source code, which
means you can view, modify, or completely replace the receiver
provided with the Toolbox.
Now just have a quick look at this example in MATLAB.
The first step is similar to what we saw earlier,
in that we set up the EHT configuration of interest,
here, at 20 megahertz bandwidth with 4,096-QAM modulation and 2
by 2 antennas.
Next we set up the propagation channel as TGax Model-B.
The first two lines within the main loop are a complete
802.11be transmitter in two lines of MATLAB,
which is very powerful.
After propagation and the addition of noise,
you can follow every step in the receiver
through the code, all the way to the final decoding of data.
Here, you can see the code for channel estimation
and demodulation, as well as equalization.
At that point, we can compute the resulting packet error
rate.
If you run the simulation for a range of MCSs,
you obtain waterfall curves, as shown here.
The final capability I want to mention
is EVM and spectral characteristic measurements.
With higher bandwidth and increased modulation order,
come greater requirements on the RF portion of the modem.
Being able to assess the impact of RF components
on the resulting spectral purity and EVM is, therefore,
more important than ever.
In this example, we demonstrate how to set up a simulation with
an 802.11be waveform of 320 megahertz and 4,096-QAM,
model RF impairments, verify compliance with the spectral
emission mask, and spectral flatness requirements,
and measure the modulation accuracy, or EVM.
You first select the number of packets,
and idle time between packets, then the exact configuration
you wish to test.
Here we have 320 megahertz and MCS 12 which corresponds
to 4,096-"AM with a 3/4 coding rate,
as well as the number of antennas and payload length.
You can also specify the upsampling factor
to use to represent bands adjacent
to the generated signal.
We then generate the waveform.
Before performing measurements, we
specify RF impairments, such as a high-power amplifier
nonlinearities and thermal noise.
On the receive side, we downsample and filter
the waveform, and then feed it to the receiver
we saw in our previous example.
Let me run the example.
The receiver recovers the constellation,
as shown on this figure, and measures the EVM of the data.
Here, you can see the EVM is around minus 47 dB.
You can also observe the spectral characteristics
and spectral flatness of the waveform.
To conclude this short video, we have seen that Wireless LAN
Toolbox offers comprehensive support for 802.11be,
with support for most Relase-1 features,
according to version 1.0 of the draft standard.
Wireless LAN Toolbox is an open environment,
as it includes full MATLAB source code of transmitter,
channel, and receiver.
And you can interface your MATLAB session
with instruments or SDR boards.
The models are useful, both for engineers looking for access
to waveforms for further testing of their system,
as well as engineers developing 802.11be algorithms who are
interested in the detail of the standard.
To learn more about Wireless LAN Toolbox,
please visit our homepage at mathworks.com/wlan,
or the wireless communications homepage shown on this slide.