Master Thesis: Beamforming Modulated Distortions and Compensation Scope in Advance Transceivers

Company Name: Ericsson

Location: Lund, M, SE

Overview

Our Exciting Opportunity 

Advancement in 5G faces steadily growing demand for variety of use cases for far higher number of users at the same time. This puts demand on utilizing spectral efficiency. One way to improve this, is by using multiple antennas. Large scale advanced antenna systems comprising hundreds of antennas perform beamforming to improve such utilization. However, such designs also become vulnerable to crosstalk due to mutual coupling between the antennas and related mismatch effects also referred as load modulation effect. These effects, together with nonlinear distortion at the Tx output build undesired radiation field properties.

This thesis will investigate technique for comprehensive analysis for compensation of nonlinear and dynamic characteristics of multi-antenna transmitters (Tx). The analysis is implemented by developing a model of power amplifier (PA) which takes joint consideration of PA nonlinearity, antenna crosstalk and mismatch effects in multi-Tx system. Also, model must be improved to consider tuning of complex characteristics of PA such as reverse isolation and return loss. To study effects of multi antenna crosstalk on transmitter linearity in digital beamforming scenario an approach of active load modulation was developed and investigated for various dynamic conditions in some of the previous researches. This thesis work builds on such experiments or results and further in consonance with the findings craft a dynamic solution of digital compensation and analog relaxation scope in active antenna systems.

Elaborating more, this work seeks to discover the scope of solving load modulation distortion effects at three different functionalities in the transmitter chain. These are digital pre-distortion (DPD) functionality, digital antenna calibration functionality and power amplifier. It is to discover the scope of these functions and their relative dynamics and weight to compensate for load modulation effects.

This include delving into simplification or relaxation into power amplifier complexity in relation to digital weighting of load demodulated DPD or modified mutual coupling antenna calibration algorithms or vis-a-vis. Hence, it’s a research to discover the individualistic and relativistic scope of these three functions and strike a balance by crafting a scope metric in terms of cost, power, area, performance, etc., to compensate for active load modulation effects from antenna array end.
 

You will

Carryout literature research about the modern work done in this area.

Crafting digital beamforming scenarios/algorithms.

Developing models for complex characteristics of power amplifier.

Analyzing the effects of mutual coupling or antenna crosstalk on transmitter linearity.

Developing/analyzing the compensations scope of antenna calibration and digital pre distortion algorithms in context.

Scope of relative weighting of digital and analog compensation techniques in relation to distortion/compensation regards to mutual coupling of advanced antenna system.
 

To be successful in the role you must have

A desire to learn new things along with the ability to collaborate and work as a team for a research work. Students pursuing their major in one of these fields are encouraged to apply. It is encouraged to be simulation and mathematically heavy work.

MSc in Electrical Engineering, Wireless Communication, Mathematics, Computer Science or similar.

 

What´s in it for you?
 

Here at Ericsson, our culture is built on over a century of courageous decisions. With us, you will no longer be dreaming of what the future holds – you will be redefining it. You won’t develop for the status quo, but will build what replaces it. Joining us is a way to move your career in any direction you want; with hundreds of career opportunities in locations all over the world, in a place where co-creation and collaboration are embedded into the walls. You will find yourself in a speak-up environment where empathy and humanness serve as cornerstones for how we work, and where work-life balance is a priority. Welcome to an inclusive, global company where your opportunity to make an impact is endless.

What happens once you apply?

To prepare yourself for next steps, please explore here: https://www.ericsson.com/en/careers/job-opportunities/hiring-process 

Work Location: Lund
Preferred Starting Date: September 2020

 

The selection process is ongoing. Please send your application as soon as possible.

Should you have any questions regarding this opportunity, please feel free to get in touch with recruiter Stefan Vasiljevic stefan.vasiljevic@ericsson.com
 

Curious to know more about the life at Ericsson? Meet some of your future colleagues and watch our People film.

 

Do you believe that an organization fostering an environment of cooperation and collaboration to execute with speed creates better business value? Do you value a culture of humanness, where fact based decisions are important and our people are encouraged to speak up? Do you believe that diverse, inclusive teams drive performance and innovation? At Ericsson, we do. 

 

 

We provide equal employment opportunities without regard to race, color, gender, sexual orientation, transgender status, gender identity and/or expression, marital status, pregnancy, parental status, religion, political opinion, nationality, ethnic background, social origin, social status, indigenous status, disability, age, union membership or employee representation and any other characteristic protected by local law or Ericsson’s Code of Business Ethics.
 

 

 

Primary country and city: Sweden (SE) || || Lund || Stud&YP

Job details: Developer