Martin secures your devices

Published: 2023-03-16

The Internet of Things requires a large number of small, inexpensive devices to be connected. To do this with a sufficient level of security is a major challenge that Martin Gunnarsson has taken on. He defends his PhD thesis ?Efficient Security...

Read more about the dissertation.
Download the thesis.

What is your thesis about?

Connected digital computing devices have spread to virtually all aspects of society. As of 2021, there are more connected things, i.e., small computers, on the internet than people. These small computers power a wide variety of things in our society, from household appliances and vehicles to power plants. One important sector that is becoming increasingly connected to the internet is manufacturing.

Industry 4.0, for example, predicts and outlines a more flexible future of manufacturing. Smaller series of custom products can be produced efficiently with distributed connected control systems without requiring complex and time-consuming retooling. Such trends in manufacturing point to a more connected, decentralized, and agile future.

The future of connected devices is scale and decentralization. Since devices are deployed at scale, they must be cheap to manufacture, deploy, and run. Wireless and battery-powered devices can decrease the cost of installation by 30-60%. Many devices being added to networks today are constrained devices, that is, devices with limited computational power, memory, and network bandwidth. Many constrained devices are also battery-powered and need to preserve energy.

Often the public is only made aware that a device is connected when a cyber attack disrupts that device's operation. The move from connected computers, servers, and networking equipment to connected Smart Manufacturing, Smart Grid, and other cyber-physical systems has moved the risks of cyber attacks from loss of capability and data to the risk of physical harm, loss of property, or even life. Technologies exist that mitigate the risk of connected IT infrastructures, and these technologies may not be suited to deployment in connected constrained devices. The limited performance of the constrained device can make such technologies too resource-intensive to be feasible. There can be thousands of sensors and actuators in a factory or a wireless sensor network, and solutions must be able to handle many deployed devices. This thesis addresses the need for efficient security protocols for new decentralized connected systems, and demonstrates that it is possible to implement and deploy secure and efficient protocols in the setting of constrained devices.

What is the most fascinating or interesting with your thesis subject?

The Internet of Things (IoT) has a poor reputation from a security aspect. An often-given reason is that IoT devices are not powerful enough to run adequate security measures. It is inspiring that my research has helped mitigate these shortfalls. I especially like working close to the hardware on low-performance devices where efficiency is critical and formal protocol verification.

How will your results be of use in the future?

Protocols we evaluated and implemented in my thesis are being deployed in products today. Our research on a security architecture based on the Digital Twin concept has been widely cited and used in further research in the field.

What are your plans?

I have a job lined up in the industry. Putting everything I have learned in academia into practice will be very exciting. I want to continue working with securing the connected devices that power our society.

Link to the article Martin secures your devices

Get your gain with Qiuyan's antennas!

Published: 2023-03-14

Wireless transmissions can be drastically improved by antennas with high gain and beam steering capability. Qiuyan Liang has investigated how such antennas can be designed in an efficient manner. On March 24 at 9.15 she defends her PhD thesis...

Read more about the dissertation.
Download the thesis.

What is your thesis about?

Nowadays the use of wireless internet has permeated many aspects of our lives, including study, work, travel, and entertainment. These ever-more-complex contents transmitted in wireless communication networks are essentially in the form of data, and ever-increasing data rates are needed to support the content delivery. The communication of information requires a transmitter and a receiver. For example, if someone transmits information by speech or body language, then the information can be received by another person?s ears or eyes. Similarly, wireless communication also requires a transmitter and a receiver, with an antenna being a critical component in each. Antennas with large frequency bandwidth, high gain, and beam steering capability are very important for future wireless communication systems. However, it is very challenging to design antennas with low-complexity structures and high space utilization that can achieve these desired features. Base stations with fixed installations and non-stationary mobile terminals play critical roles in wireless communication networks. Therefore, this thesis focuses on the low-complexity multiband and beam-reconfigurable antenna design for the two applications.

Antennas based on partially reflective surface (PRS) can provide high gain with simple structure and low cost, which have good potential for application in future base stations. The first topic of this thesis is on enhancing two aspects of PRS antenna design, namely beam steering capability and shared-aperture antenna design. Existing PRS antennas mainly use standard reconfigurable approaches for beam steering, e.g., using reconfigurable loads on the PRSs? unit cells. The beam can be pointed towards different directions in different reconfigurable states. However, current beam-reconfigurable PRS antennas suffer from narrow coverage range, distorted beam shape and considerable gain variations over the beams in different directions, which may lead to degradation of communication quality. On the other hand, shared-aperture antenna design with PRS aims to integrate antennas working at different frequency bands into a shared space to provide high space utilization. However, existing design schemes suffer from inflexible frequency ratio (of the bands) and bulky antenna structures. Therefore, the main part of my thesis deals with the research question on how to solve the challenges encountered by PRS antennas with respect to beam reconfigurability and shared aperture designs, while maintaining low-complexity structures.

Figure 1: Base station and user device antennas in high frequency applications need to be capable of beam steering with high gain.

Besides base stations with fixed installations, wireless communication networks consist of a large number of user devices, including mobile terminals. With the rollout of 5G, terminal antennas are being developed to cover both existing and new 5G frequency bands, spanning both sub-6GHz bands and mm-wave bands. To save antenna implementation space, it is desirable to co-design and even co-locate these antennas. However, existing co-design approaches suffer from complex structure of the mm-wave antenna and low space utilization. Therefore, the other part of my thesis is about solving the research question on how to co-design the sub-6GHz and mm-wave antennas for mobile terminals for compactness and low-complexity.

How will your results be of use in the future?

Antennas have already been widely applied in practice and a larger number of antennas will be deployed in future wireless communication networks. My research provides low-complexity PRS antenna designs for base stations and co-designed antennas for mobile terminals. Therefore, I believe that the results from my research have the potential to contribute to the development of more cost-effective wireless communication networks by improving system architecture and saving installation resources.

Link to the article Get your gain with Qiuyan's antennas!