Student project: Digital Pre-Distortion for ADPLL and Class-D PA

*Important for non-EU students: You'll need to be registered at a Dutch university to meet immigration requirements.

In this project, the student will investigate the application of digital predistortion (DPD) algorithms and implementations on real world hardware, a 6 GHz transmitter. It includes measuring AM-PM and AM-AM distortion on existing hardware, modeling the mechanisms in MATLAB, designing a sufficiently accurate and low-power mitigation system, and trying it out on the hardware. If time allows a digital implementation can be designed in Cadence. This project is especially suitable for students who are passionate about RF transceivers and solving challenging real-world problems. 

What you will do

The most recent specification development by the Bluetooth Special Interest Group involves adding higher bands (5-6 GHz) to the existing 2.4 GHz and employing higher data throughput up to 8 Mb/s using 16-QAM at 2 MSym/s. The most efficient transmitter uses a polar architecture, giving us access to the digital codes for both AM and PM, simultaneously. We can even upload our own predefined AM and PM waveforms to the chip for playback.  

In this project, we’ll use state-of-the-art algorithms to linearize the PA’s AM performance as well as compensate for the AM-PM distortion caused by various feedback mechanisms between PA and ADPLL. The goal is to maximize the average TX power level at which the PA operates, while fulfilling error-vector-magnitude (EVM) and regulatory constraints (ACPR). 

The student will use one of the latest IMEC transceiver chips to characterize static and dynamic distortions, model the mechanisms in MATLAB, design cancelation strategies that mitigate the distortion at minimum added power consumption, and validate their design by trying them out in the hardware. If the existing mitigation options in the chip prove insufficient, the prototype (MATLAB) system can be translated into a digital design for inclusion on-chip. 

Your tasks involve:

• Literature survey on distortion mechanisms and their mitigation strategies (5%) 
• Characterize and model the distortions, and develop a DPD system in MATLAB (60%) 
• Verifying the accuracy and calibrating the designed system in the lab (10%) 
• Thesis (25%) 

What we do for you

You will be working on cutting-edge research on a topic that is relevant to academic research and industrial applications. To help you in this journey, we offer a flexible environment where you can be the leader of your own research while having the support of experts from signal processing and systems design to complete your tasks. As part of the Signal Processing team in IMEC-Netherlands, you will have opportunities to learn from some of the best minds in analog and digital circuits, data science and other research domains.  

Who you are

• You are a MSc/BSc student in Electrical Engineering or Data Science
• You have affinity with RF design and digitally assisted analog design
• You have basic knowledge of signal processing
• You are available for a period of 6-8 months
• You are familiar with system-modelling in MATLAB
• You are self-starter and able to work independently
• You are entitled to do an internship in the Netherlands
• Good written and verbal English skills 

Interested

Does this position sound like an interesting next step in your career at imec? Don’t hesitate to submit your application by clicking on ‘APPLY’.
Should you have more questions about the job, you can contact jobs@imec.nl.