Did you hear about Qualcomm Technologies’ (QTI) launch of QFE1100, the first ever Envelope Tracking (ET) chipset for a 4G mobile device? It’s big news for the mobile Industry and if you want, you could check out the QFE1100 by tearing apart your brand new *Samsung GALAXY Note 3. Okay, I could save your device and help you learn more about the QFE1100—all you have to do is read on.
So why is the QFE1100 big news? To put it simply, QTI has finally delivered one of the industry’s most sought-after radio technologies—ET. ET, long confined to R&D labs as a promising but complex mobile RF technology, is finally seeing light of day in the Samsung GALAXY Note 3. ET is also critical to the performance of another upcoming RF product from QTI—the innovative Qualcomm® RF360™ front-end. So, this is big news for QTI as it has (1) validated an important piece of the RF360 front-end, and (2) met a timely need of the mobile RF industry, especially given the transition of the industry to 4G LTE.
But what’s special about 4G LTE? A lot actually, but what matters for ET is signal variation and amplification. The LTE signal is different in that it is formed by adding several hundreds of smaller signals together while the 2G/3G signal in comparison is only a single waveform. Adding signals introduces variation at the summed output because as you can imagine, whenever the peaks of the smaller signals align, a much larger output signal will result. Moreover, for larger bandwidth LTE, thousands instead of hundreds of small signals have to be added leading to even more variation in the output LTE signal.
But signal variation hurts amplification! A conventional power amplifier (PA), the component in a phone that magnifies your signals so that they can reach the cell tower, works with a fixed supply voltage and is power efficient only at the peaks of the transmitted signal. To accommodate a highly varying signal, the fixed voltage is typically set much higher than it needs to be and ends up being dissipated as heat inside the PA as well as wasting battery life.
Imagine how you would feel if your heart always pounded at peak rate (say, 200 bpm). You would be wasting energy and generating excess heat even at rest because you only really needed your heart to beat at 72 bpm! Just as the heart continuously adjusts the blood supply to track our output activity levels, the ET chip (QFE1100) adjusts the PA power supply to track the envelope of the PA output signal level.
ET is designed to result in a more reliable amplified signal with up to 20% improvement in PA power efficiency and up to 30% improvement in heat dissipation. This directly correlates to longer battery life and not just cooler mobile devices but cooler-looking devices, because reduced heat enables thinner form-factors. In addition, the ability to efficiently amplify wider bandwidth LTE signals allows handset manufacturers to design devices with global LTE coverage at lower cost with fewer broadband power amplifiers addressing the wide range of LTE frequencies deployed worldwide.
With commercial availability of QFE1100 chipsets that are enabling the next generation of 4G LTE mobile devices, QTI has indeed pushed the envelope in mobile RF performance. As QTI continues to redefine the boundaries of RF and modem performance, you can bet I will be back with my next blog very soon!
*The processor may differ by geographical region.