“One of my first memories relating to the word ‘drones’ is that of an online video of a man. He was angry and revengeful [and] told the story of how he lost his whole family,” Samira Hayat began her talk at the 2016 TEDx event Ripples of Curiosity at the European research center CERN near Geneva on November 5.
In mobile communication systems, like UMTS or WLAN, the transmissions of different mobile devices interfere with each other. For example, when a mobile device transmits signals to its base station, other mobile devices transmitting on the same frequency band cause interference at that base station, which in turn may result in decoding errors in the intended signal. This form of interference becomes more and more relevant with the increasing number of wireless devices, and defines what is known as an interference-limited network. The number of incorrectly decoded bits per unit time is the bit error rate in the network.
Time synchronization is an essential building block in wireless sensor networks but is challenging due to low-precision oscillators and limited computational power of cheap devices. A novel synchronization solution for such scenarios is now proposed by Wasif Masood together with his advisors Christian Bettstetter and Jorge F. Schmidt from the University of Klagenfurt.
Synchronization algorithms based on the theory of pulse-coupled oscillators are evaluated on programmable radios. It is experimentally demonstrated that the stochastic nature of coupling is a key ingredient for convergence to synchrony. We propose a distributed algorithm for automatic phase rate equalization and show that synchronization precisions below one microsecond are possible.
New packages for the Robot Operating System (ROS) are available for autonomous exploration of unknown environments using collaborating mobile robots equipped with cameras. The software offers wireless ad hoc communications between robots, merging of maps from different robots, and coordinated selection of exploration frontiers. A prototype with four robots was built that demonstrates its functionality in an indoor environment.
Wireless networks are often modeled using tools from stochastic geometry. A team of researchers from Klagenfurt, Athens, and Notre Dame now contributed to these tools by solving general sum-product functionals for Poisson point processes. Link outage probabilities are derived for networks with interference and Nakagami fading.