Critical demands on wireless networks

The wireless communications has revolutionized the manner in which humans communicate. In the new generations of embedded systems, people, autonomous devices and the environment will interact with each other. This increase our demands on the performance of communication networks, in particular regarding the so called real-time constraints, where the reaction time in for example an autonomous could be the difference between life and death.

The growing evolution of wireless communication — and all the new applications enabled by it — drastically increases the demands on the performance of communication networks.

But implementing time critical applications over wireless networks is still a challenging task. Today, wireless links are more unreliable compared to wired counterpart. In an audio/video application, missing deadlines will only result in a temporary lowered quality. On the other hand, data from the real-time system used to control the airbag in a car becomes useless if it arrives after the car has already crashed.

The dashboard of a car with a deployed airbag hanging from the steering wheel

”The real-time requirement implies that not only the result itself is of importance but also when in time it is presented. In real-time communications, each message has a deadline to meet, and what happens when the deadline is missed varies with applications”, says Le-Nam Hoang who recently successfully presented his doctoral thesis ”Relaying for Timely and Reliable Applications in Wireless Networks”.

Calculations on a probabilistic view on wireless networks

In his thesis, Le-Nam Hoang uses a probabilistic view of fulfilling the real-time constraints in wireless networks. The aim is to provide a sufficiently high probability of delivering correct information before the deadline. Different applications will have different requirements on the level of reliability needed. Wireless networks must be able to fulfill all requirements that current wired field buses do today, in terms of guarantee sufficient levels of reliability and timeliness. Therefore, providing both timeliness and reliability for wireless networks in industrial settings is an important remaining challenge.

”Many of these new wireless applications are subject to time-critical constraints especially ones related to human safety. Once these constraints are violated, the consequences may be severe. Therefore, the aim of my thesis is to fulfill the real-time communication constraints in such applications.”

The doctoral thesis is a part of two projects

During his doctoral studies, Le-Nam Hoang has been involved in two research projects, ELLIIT (Excellence Center at Linköping-Lund In Information Technology) and ACDC (Autonomous Cooperative Driving: Communications issues). ELLIIT is a collaboration with Linköping University, Lund University and Blekinge Institute of Technology. With ACDC, the partners are Kapsch TrafficCom, Qamcom, Scania, Volvo Cars, and Volvo Group Trucks Technology.

Le-Nam does not hesitate when asked what his future plans are:

”Research, definitely! There are still many arising research questions in this field that I would like to tackle.”

Text: Tove Nordén and Le-Namn Hoang
Photo: iStock

Read more

Thesis: ”Relaying for Timely and Reliable Applications in Wireless Networks” External link, opens in new window.