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.
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.
Wireless communication from a sender to a receiver is significantly affected by the interference generated by other devices. If devices in the vicinity of the receiver transmit at the same time and on the same frequency channel, their signals interfere at the receiver with the intended signal from the sender and thus impede proper reception.
Multiple-access interference in wireless networks has significant impact on diversity techniques and protocols. Bettstetter and Schilcher aim at gaining a deeper understanding of interference dynamics and to rigorously analyze its impact on system performance. They secured funding by the Austrian Science Fund (FWF) in the order of 350.000 EUR for their new project INDY. “The proposal exhibits an excellent understanding of the problem for investigation”, one of three anonymous reviewers says.
Interference has significant impact on the performance of wireless communication systems. A comprehensive understanding of its dynamic behavior over time is important for the design of diversity schemes and protocols, whose performance can severely degrade in case of highly-correlated interference. Schilcher, Bettstetter, and Brandner aim at advancing this emerging field from a theoretical perspective. Their forthcoming article to be published in the IEEE Transactions on Mobile Computing derives closed-form expressions and calculation rules for the correlation coefficient of the overall interference power received at a certain point in space. “We take into account three sources of correlation: node locations, channel, and traffic,” Schilcher says. It took the team more than one year to find solutions for 27 scenarios presented in the article. The hard work payed off. Schilcher recently also defended his doctoral thesis with distinction. “This is an important research direction,” the external PhD examiner, Martin Haenggi from the University of Notre Dame (USA), says. “The spatial and temporal structure of interference has been largely ignored, although it is critical to the performance of …