Shining a Spotlight on Software Defined Radio

NXP has been working with community driven efforts to support a new Software
Defined Radio (SDR) platform  that allows
both industry and academia to bring new products and innovations to the world. The ultimate goal of this initiative
is
to make development hardware affordable for everyone and easier to use by making it software-centric.

What is the importance of the SDR platform?

The entry barrier to development of new hardware and software can be a struggle if you don’t have “large company”
resources or are not well-connected in the industry to make up for this. One of the reasons for technological progress
over
time is that hardware complexity keeps increasing. For example, designing and building a PCB is a lot more complex these
days
than a couple of decades ago. On top of this comes software complexity. Operating system, driver and application
complexity all are increasing beyond what a single individual can manage.

So, what is the industry doing to fix this? The answer is typically reference design kits and single board
computers. As an example, see the microcontroller space where MCX microcontrollers are enabled with FRDM Development Platform kits that
allow
partners to quickly come up to speed.

This is a great concept but rarely extended into an area as complex and “heterogeneous” as the telecommunications
space
where analog, digital, signal processing, radio frequency and traditional compute all blend into a single hardware/software product.

This is the challenge that the LA9310 Software Defined Radio (SDR) product tries to address. We’re not sure whether we can
claim a “world’s first” here but it’s certainly innovative in providing an FPGA-less (and thus easier to code) SDR
platform at an extremely aggressive price-point.

Read the interview with Harsha Master (Principal System Architect, CTO office) and Wim Rouwet (Senior Principal
Engineer, Secure Connected Edge) to learn more about this exciting project:

Q: What sets this project apart from the rest?

Harsha: It’s the first of many – cost, size, features, flexibility, reconfigurability and more.
Popular cost-effective SDR
Modems on the market are FPGA based and feature-specific with fixed applications. NXP Long Term Innovation (LTI) SDR
Development Platform uses a highly efficient programmable baseband processor LA9310.

On the market, SDR modems of the same capability are roughly 4-5 times more expensive, and better ones are even 20
times
expensive. For example, this NXP LTI SDR board is about 250 USD, similar ones on the market are about 2500 USD.

Traditional cost reductions are due to reduced features, reduced speed and computational power, and fixed
configuration.
What is envisioned in NXP’s LTI SDR board is cost and a wide range of applications and features.

The NXP LTI SDR main board is a fixed layout with baseband processor LA9310 and host processor i.MX
8M Plus to make
the
system as stable as possible. Daughter boards can be pre-made, custom-built by the developer or chosen from third
parties or vendors.

Wim: These daughter boards can either pin out analog (baseband IO), implement wireline or wireless
communication protocols or
even functions like digital oscilloscope or Vector Signal Analyzer. Mix and match at its best!

From the software side, this project supports multiple open source initiatives. For example, look at the 5G world
where
we from NXP are putting quite a lot of our focus.

Here, stacks from the likes of OpenAirInterface, srsRAN, open5GS or open5gc apply. Or, 3rd party commercial vendors
of
course. Vicinity Wireless  from
Bristol/UK
developed a 5G UE on this platform.

Of course, we support NXP internal development teams as well as startups and academia on this platform.

Q: Please tell us a little more about the different technologies behind this.

Harsha: LA9310 is NXP’s most efficient, low-power baseband processor. It is also a popular
entry-level baseband processor,
cheaper in cost, and does not have complex export control restrictions. Unlike FPGA-based systems, NXP LA9310 is
comparatively faster, compact and low power, yet flexible with programmable capabilities. Developers can use it as
a modem, signal generator, or signal analyzer by rightly selecting plug and play RF modules.

i.MX 8M Plus is a very popular NXP MPU with unique capabilities, including four core processors, a TSN endpoint and
hardware accelerators for AI/ML, camera/video and IoT, to name a few applications. i.MX processors are widely used
in
Automotive, Industrial, Robotics and Medical domains. In LTI SDR, it is used as a central control processor and runs
required software stacks. For example, the entire 5G Layer 2/3 will run on i.MX 8M Plus.

SN220 is one of the proven combo NFC-eUICC-Secure Element solution in the mobile
market. It interfaces uniquely in
the
system, enabling developers to use it as a “real modem” without using a plastic SIM card but with an embedded SIM.
Developers can further use their imagination to use them in many combinations.

Q: So, what does it take to start such a project?

Harsha: This is really a case of “better together”, both inside NXP across groups and outside with
the larger ecosystem. It goes
back a bit to what we talked about at the beginning with enablement typically being done on a per-product basis and
best-in-class for the simpler products. At the same time, we see that the software enablement and support for
typical
large customers as done by NXP is not the same as what start-ups, academia and open source communities want. On top
of
all of this, we need to achieve an aggressive price point.

Wim: So, to achieve all of this, we decided pretty early on with an external partner initiative
called RFNM who are much more
in tune with the ecosystem needs. Sure, there’s some NXP expertise ongoing “behind the scenes” but it is amazing to
see
what a community can do – way more creative application thinking than we could come up with ourselves. What has been
helpful is the push from the community to make the platform open: BSPs, drivers et cetera are already NXP
published/supported open source and we’re trying to get more “out there”.

Q: Let’s ask RFNM what their view on this is.

Davide Cavion (RFNM): As someone that always dreamed of building an SDR and the ecosystem around it,
the LA9310 was a godsend. Wim already
touched on the lack of an onboard FPGA, but there is another important difference: the LA9310 comes with an analog,
I/Q
baseband interface. Unlike other products on the market, that use a chip integrating frontend, mixer and ADC, this
lets
us split the signal path between mixer and ADC on a board to board mezzanine connectors. If this sounds confusing,
let
me just jump to the conclusion: we only need to develop a motherboard once, taking care of all of the software and
digital side, and customers can very easily develop daughterboards starting from a simple Altium template.

Q: Are there any tie-ins with industry buzzwords like 5G advanced, 6G and AI/ML?

Wim: As you would expect, within NXP we are working on all of these topics. But we’re also seeing
that a lot of the
underlying research is very open in nature. So, we’re enabling academia and startups with these boards so that they
can
start getting practical experience with new waveforms that are enabled by the programmable nature of the platform,
or
with AI/ML as included in the i.MX 8M Plus processor. There are some obvious limitations to what a low-cost
development
board can provide in terms of RF bandwidth, but then again, scaling up is often a more mechanical exercise as
compared
to inventing something fundamentally new. On top of this, if you take the view that 6G will likely be more open,
software-defined and ad-hoc in nature and this type of platform being exactly what the industry will be looking for
in
the future. So yeah, we’re pretty confident this SDR will be a part of a 6G future.

Q: When can users expect to get their hands on this?

Harsha: Now! Late 2023 was the time in which software was done, and hardware and software were
validated to work. Boards
have been shipped during early 2024 and software has been evolving ever since. You can order the platform directly
via
the RFNM website .

Q: What’s next?

Wim: Well, there’s a lot of work to be done still. The first batch of boards is built with the
second batch hopefully
opening up soon. Better get yourself signed up quickly if you want one. What we are seeing from our side is a bunch
of
new customer engagements based on this project. All these customers need to be supported to build their projects,
demonstrate, optimize and commercialize them. That all takes time and effort that we are going through right now.
You
should be seeing the silicon on that SDR board making its way into commercial products in the next year or so.

Harsha: At the same time, we’re looking at whether we can build a “big brother” of this system. More
bandwidth, more
compute, and so on. This would give a scalability to the platform that is missing right now. Ideally, this will also
be
“crowdfunded” and at the same time backed by NXP because it worked out well this time.

Authors

Harsha Master

Harsha Master is a Principal Systems Architect at CTO Office, NXP Semiconductors. With primary focus on Industry 4.0 & beyond 5G, he supports both internal and externally funded 5G/6G industrial innovation projects. Harsha has a rich background in design/developing software stacks for feature phones, satellite devices and media/signalling gateways. He has also designed architectures for local connectivity platforms and early smartphone systems. Harsha is deeply passionate about networks, communication and security.

Wim Rouwet

Wim Rouwet is a Distinguished Member of Technical Staff at NXP Semiconductors. Focused on 3GPP LTE and 5G as well
as 802.11 processing stacks and their implementation, Wim is responsible for 4G and 5G stack development, small
cells, and CRAN implementations associated with many wireless infrastructure projects.

Special thanks to Francois Massot-Pellet and Fabian Mackenthun.

Project is supported by NXP’s Long Term Innovation and executed under Industrial Innovation Board.