Student Project: Optimizing for sub-5cm Range Errors: Phase-based Range Estimation on BLE

We intend to optimize the accuracy of phase-based ranging in the context of Channel Sounding
(CS); to this point, we focus on evaluating and benchmarking different approaches of channel
reconstruction and ranging under a wide set of constraints (i.e., energy consumption, delay,
range error).

What you will do

The advent of power efficient micro-controllers, circuit minimization, and energy scavenging has
led to a dramatic increase of wireless devices. Such devices are widely utilized in asset-tracking,
secure proximity, radio commissioning, and localization. Ranging, i.e., determining the distance
between the devices participating in these applications, is considered essential application-wise.
Bluetooth Low Energy (BLE) technology is an attractive protocol for ranging as it operates in the
2.4GHz ISM-band without the need of a license. BLE is already used by millions of wireless
radios, being integrated in our everyday lives, e.g., mobiles, smart homes, airports, and critical
infrastructure.

Among ranging techniques, phase-based ranging offers improved precision, as it is based on the
principle of the shift (or rotation) of the phase of a signal as it propagates, depending on the
signal-frequency and the distance it covers.
BLE networks use phase-based ranging in the context of Channel Sounding (CS). In CS, a pair of
devices, Initiator and Reflector, alternate their roles in transmitting and receiving in a coordinated
way to measure the phase shift of the signals they send to each other. By repeating the above
process across the 80MHz BLE frequency band range ambiguities are eliminated, enabling 10cm
accuracy for various applications.

Our goal is to redefine the above state-of-the-art in CS, by guaranteeing a range error on the
domain of 5cm. To this point, we need to identify and compare the best practices on the
domains of: (i) Channel Reconstruction and Recovery, and (ii) Ranging Estimation, for a wide
range of constraints regarding the propagation environment, the device characteristics, and the
CS scenario specifics. The hardware platform of choice is the Nordic Semiconductors nRF52833-
DK.

Student Tasks:

• Literature review on the state-of-the-art in phase-based ranging.
• Study on the Channel Sounding in the context of the Bluetooth Low Energy protocol.
• Study of the different mechanisms introduced by Imec on channel reconstruction and
  recovery.
• Study of the different techniques introduced by Imec on ranging estimation.
• Program the external nRF52833 node with an own implementation of Bluetooth Channel
  Sounding.
• Learn to produce and characterize In Phase and Quadrature data under different scenarios
  using the nRF52833-DK.
• Perform complete theoretical and experimental comparison of the Channel Sounding
  algorithms of Imec using the nRF52833-DK. Showcase their trade-offs regarding range-error,
  delay, and computational cost.
• Propose improvements on the state-of-the-art in the ranging accuracy of Channel Sounding.
• Evaluate/validate the improvement on-field using the nRF52833-DK.
• Thesis writing and documentation at imec-Holst Centre.

What we do for you

Imec has been working on RF-based ranging and positioning implementations and evaluation for
more than 10 years. Imec is a world-class research institute, in the center of excellence in
Connectivity Technology, with top licensees and partners on the domain of Bluetooth Chip
providers. Imec is pioneering the phase-based ranging since 2018, with the creation of the
world's first phase-based ranging mechanisms. Imec's algorithms achieve state-of-the-art
accuracy of 10cm on standard BLE radios.

Imec’s ranging program has been started in 2016. It comprises a large team of experts in
wireless system and algorithm development, measurement and evaluation and embedded
software, and leverages Imec’s expertise in ultra-low power wireless circuit and system.

In Imec you will be supervised by world-renown RF-researchers. You will collaborate with experts
in the field of wireless systems and algorithm development. Further, you will experience all
aspects of a research project, from the theoretical application of new ideas to their on-field
evaluation using the latest hardware platforms of our world-renowned partners.

Who you are

• MSc student from Technical University. Domains: Electrical Engineering, Telecommunications, Wireless Networks.
• Creative and hard-working.
• Eager to expand the state-of-the-art (patents, publications).
• Hands-on person with inclination to experiments.
•  Prior experience with Bluetooth/BLE.
• Prior experience with embedded programming (C/C++) and Python
• Entitled to do an internship in the Netherlands, Eindhoven.
• Academic level of English.
• Skillful presenter and communicator.

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 NOW’.
Should you have more questions about the job, you can contact Nikos Kouvelas at nikos.kouvelas@imec.nl .
Got some questions about the recruitment process? Martijn Kohl at jobs@imec.nl the Talent Acquisition Team will be happy to assist you.