Hi.
In today's demonstration,
we will be looking at
how we can reduce the energy consumption
of cellular base stations.
Saving power serves two key purposes.
First, it can reduce significantly the operational costs.
And in addition, it provides an important step
towards addressing climate action.
In our first demonstration,
we will be focusing on power amplifier optimizations.
Power amplifiers are a major source
for power inefficiency in base stations,
since they are operated
at a very inefficient operating point.
If one would try to increase the power efficiency
of the power amplifiers
by reducing the power amplifier headroom,
the result would be a significant loss in signal quality.
We therefore offer a combination
of signal processing-based techniques,
including peak-to-average reduction methods,
digital pre-distortion assisted by the mobile phone,
and digital post-distortion methods,
in order to suppress the non-linearities
induced by the power amplifiers
and enable them to operate
in the more power-efficient operating point.
In our demo, we will be using digital post-distortion,
which does not require any change
in a base station hardware.
Here you can see our lab setup,
where we are transmitting a signal
through a typical power amplifier,
receiving the signal,
and analyzing the signal quality
with and without our DPoD technology.
Let's look at our lab results.
And as an example,
let us look on the operating point of 64-QAM modulation.
As can be seen, trying to move the power amplifier
to a more power-efficient operating point,
results in a significant loss in the signal quality,
which adversely affects the communication link.
With our digital post-distortion technology,
we can suppress the non-linear distortions created
by the power amplifier
and allow it to operate
in its more power-efficient operating point.
Moreover, the new signal quality
is actually better than the baseline,
allowing to increase the spectral efficiency
by transmitting higher power
and improving the communication link.
In this demonstration,
we have seen how digital post distortion can save 50%
of the energy consumption of power amplifiers,
and at the same time significantly increase
the spectral efficiency.
- In our second demonstration,
we're going to show you a technique
where we cancel some of the radio transmission impairments
to allow us to operate at a higher-order modulation.
We call this technique Super-QAM.
As we will show, with this technique
we can significantly increase the peak data rates.
In our lab result in the sub-7 GHz spectrum,
we're able to move up from 256-QAM to 4K-QAM,
and in the millimeter-wave spectrum from 64-QAM to 1K-QAM.
Our lab setup is similar to the previous demo,
except that in this setup,
we use our mobile test device
with Snapdragon X50 5G Modem-RF system
to receive the signal that we then process offline.
Our approach is to iteratively cancel impairments,
starting with the phase noise floor,
then the non-linearity noise floor,
followed by the IQ-imbalance noise floor,
and then do it all over again multiple times.
To use this technique,
we do need some modification to the physical layer,
so this is a candidate for future 3GPP releases.
Important to note
is that there are no changes to phase noise
and linearity requirements,
which means that you can use the same RF components
in base stations or mobile devices.
Let's show an example
of a received 1K-QAM signal
before applying our Super-QAM technology.
As you can see in this IQ plot,
the signal looks very garbled,
and to the right
you can see the signal quality measured in EVM
is insufficient for proper decoding of 1K-QAM.
If we apply Super-QAM technology,
you can see how the signal quality is monotonously
improving for each iteration.
After six iterations,
you can see that the signal quality looks very good
and is sufficient for proper decoding of 1K-QAM.
If we compare to where we started,
we see that we have improved the signal quality
by an impressive 18 dB.
This signal quality gain
results in big surge in peak data rates,
as much as 50 to 66%.
As we have seen in this demonstration,
Super-QAM technology can increase
the peak data rates significantly.
This is not only great for the users,
it also allows the base station
for shorter transmission duration
and therefore reduced power consumption.