Meet the inventor of Qualcomm Smart Transmit.


Meet the inventor of Qualcomm Smart Transmit, a breakthrough technology that improves uplink speed and coverage for 5G

Today’s smartphones include a variety of radios that transmit using a variety of technologies – from 2G to 5G, Wi-Fi and Bluetooth – and antennas that cover multiple frequency bands. Improving the use of these radios requires a deep understanding of the complex radio frequency systems in the phone – and this is where Lin Lu of Qualcomm Technologies (vice president of technology) comes in handy.

Its key work in Qualcomm Smart Transmit technology uses advanced techniques to intelligently manage power transmission across multiple antenna arrays, resulting in significantly increased coverage, better uplink speeds and reduced latency. – It is especially important that modern 5G devices and networks meet high expectations. Ensuring compliance of equipment with regulatory requirements.

We recently spoke with Lin about the inspiration behind the Smart Transmitter and his biggest innovations as head of the core engineering team.

The following discussion has been edited slightly for clarity and length.

Most of your work focuses on electromagnetic interference (EMI) and radio frequency (RF) transmission. How did you master these areas?

I started working at Qualcomm in 1996 as a regulatory engineer. I worked in the commercial base station division and later moved to the handset division to work on projects to ensure that all commercial devices that Qualcomm was developing were electromagnetically compliant. ۔ Our team focused on commercial products.

In 2006, I started working with OEMs to ensure that their end products meet regulatory requirements. Qualcomm then expanded into new technologies such as wireless charging systems for mobile devices and vehicles. To do this, we needed to develop a new method to assess the electromagnetic and radio frequency exposure of these wireless charging systems, as the current certification testing procedure has yet to be defined.

Around 2010, when 5G was introduced, we identified a significant challenge to meeting the current regulatory requirements for 5G commercialization while delivering the increasing levels of performance that 5G promises. Done, that is, the existing method of assessing radio frequency exposure will interfere with the new 5G technology. .

The traditional diagnostic method was based on the decades-old assumption that consumer products (the industry term for devices such as UEs and phones) reach their maximum power level at any given time. With this assumption of maximum power, the traditional method has been used for over 30 years.

However, in most transmission cases, the UE’s transmission power is not close to the maximum power and it naturally “bursts”, meaning that the phone does not transmit all the time.

Because of this, the heritability estimation method was extremely conservative. We believed that this would be a barrier to commercial 5G deployment, especially in simultaneous transmission scenarios using multiple antennas in a single device.

So it inspired me to develop a unique solution to manage RF exposure using new techniques, and that’s why I’m focusing on this unique area of ​​Qualcomm.

How would you describe EMI and RF exposure limits for someone with limited technical knowledge?

It is easy and not easy. EMI is basically to eliminate interference between devices or devices. Take, for example, your mobile phone. You don’t want to interfere with other devices like the TV.

If you turn on the TV and the quality of the connection on your phone suddenly deteriorates, this may be due to interference from other electronic devices and devices.

With regulatory RF exposure limits, the goal is to determine how much radio energy a device can safely omit – RF exposure regulations determine the allowable energy for uplink transmission, which ultimately determines the performance of a wireless device. IS.

Improving RF output helps improve things like uplink bandwidth, latency, and coverage, helping to ensure that calls are dropped, videos are easily downloaded, and more.

Editor’s note: EMI and RF exposure limits are mandatory requirements regulated by every market in the world, including the US Federal Communications Commission (FCC).

What discoveries allowed you to estimate the limits of transmission power more than half a decade before the introduction of 5G mmwave technology, and how did these discoveries ultimately influence the development of 5G mmwave technology?

Therefore, the traditional approach, which has been in vogue since the 1990s, assumed maximum power transfer 100% of the time. He is the one who fixed the static cap for power. However, 5G is very dynamic, which means that the uplink duty cycle, by definition, can vary from a small percentage to 100%, and the operating frequency range covers all 6 to mm waves.

If we constantly assume the worst case scenario, the expected performance requirements from 5G networks will never be met due to this old approach of managing RF exposure by statically limiting uplink transmission power. Obviously, we need a breakthrough.

We found that transmitted power ranges and most transmissions are often nowhere near this maximum power. So we knew we had to be able to support high-powered bursts of data as needed.

My idea then was to improve UL’s real-time performance by using banks and wasting power during periods of low usage when there is a demand for more powerful data traffic – like being indoors and uploading videos or photos.

This device ensures that the average transmission power does not exceed the permissible energy limit in a given time window. Like running most of the time during a race, then running in short bursts when needed, but keeping the average speed constant. This allowed us to maximize the original bandwidth and unlock the full potential of 5G.

Can you tell me how this technology improves uplink speed and increases coverage? And why is it so important that the antennas in modern mobile devices meet the power limits of radio frequency transmission?

This is important because, as I mentioned earlier, any Affiliate must promote any program. Without compliance, no product can be launched, which is why it is number one. These issues need to be addressed on all devices before they can reach the market. This is mandatory.

Now, how does this technology increase coverage and make 5G possible? Smart Transmit technology allows us to dynamically improve radio transmissions so that when a strong uplink is needed, we can access it, and in most cases when it’s not, we can save that power in a time window. This ensures more reliable connections, fewer calls and more.

This seems like a very practical area for engineering testing in mobile technology – can you tell us how you came up with these ideas? Is it based on innovation, discipline focus, or both?

I would say they are both. Engineers come up with ideas to solve problems. In my case, when that happens, we need to clarify the validation process by developing new test methods and test cases. First, because we are developing new technologies. Second, any commercial device must demonstrate compliance before being launched on the market.

Once we have a technology that we think will work, we need to focus on making it compliant with current regulations. From there, we need to develop certification procedures and test cases, and then prove that we’ve worked hard and show them that our new idea works. In parallel, we must work with other industry stakeholders, such as Standard Groups and commercial test equipment suppliers around the world, to standardize new test procedures and run test cases for everyone. May be

So we have this invention, we’re ready to develop the technology, and once we get there, according to the regulations, we have to do everything else to make sure the technology is accepted. And commercialize through our partners worldwide.

How has Qualcomm helped you in your endeavors as an inventor? How would you describe the culture of innovation at Qualcomm more broadly?

I’ve talked before about turning an invention into reality and that it takes a cross-functional team. In our case, you can see it from proof of concept to implementation, to regulatory adoption, and to commercialization.

We get support from across the company – not just from the regulatory team, but with systems engineers, software engineers, product management, various local and regional teams, the customer engineering team, test engineers, everybody.

It is really needed and we have the support of the entire company. I want to see my accomplishments as the success of a team effort. Qualcomm is a company that encourages all of us to come up with new ideas and provides all kinds of freedom and support.

Finally, what advice would you give to other inventors?

Based on my experience, there are three tips: enjoy what you do, be persistent, and collaborate. Enjoying what you do naturally leads to motivation and creativity.

Then persistence will help you come up with a good idea and turn it into reality. Last but not least, co-op is important because every major innovation requires a lot of team effort. My team would not be where we are today without the support of many other teams.

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