Seminar - Optimal Beamforming in Interference Networks with Perfect Local Channel Information
Prof. Dr.-Ing. Eduard A. Jorswieck, Chair of Communications Theory, Dresden University of Technology, Germany
Thursday 3rd of June 2010, 14:00h (sine tempore), 1hour incl Q&A
Sal Tellus, Etapp VIII, Soft Center, Ronneby
We consider multiuser settings in which systems simultaneously utilize the available communication resources. Since the performance of the systems is usually limited by mutual interference, designing efficient resource allocation schemes for such scenarios is important. In general, the systems' joint operation is desired to be Pareto optimal. However, designing Pareto optimal resource allocation schemes is known to be difficult. In this work, we assume all transmitters apply multiple antennas and have perfect local channel state information of their own channels to all single-antenna receivers. Restricted to a set of feasible transmission strategies, each transmitter is associated with a power gain-region. This region is composed of all jointly achievable power gains by the transmitter at the receivers. We prove that the boundary of the power gain-region is convex and always achieved with single-stream beamforming. Due to these properties, the efficient beamforming vectors that achieve its boundary part in a specific direction can be characterized by real-valued parameters between zero and one. According to the network setting and the monotonicity properties of each receivers utility function, the important boundary part of each transmitter's gain-region is determined. Thereby, we characterize the set of Pareto efficient beamforming vectors. Motivated by cognitive radio scenarios, we provide an alternative characterization of Pareto optimal operating points through the design of null-shaping constraints on noncooperative secondary transmitters. This characterization further simplifies the design of efficient distributed resource allocation schemes. One example, including broadcast and multicast data, illustrates the results.
Eduard A. Jorswieck is Professor and Head of the Chair of Communications Theory in the Faculty of Electrical Engineering and Information Technology at Dresden University of Technology (TUD) in Germany. He joined TUD in February 2008. He has previously been Post-Doc and Assistant Professor at the Royal Institute of Technology (KTH) in Stockholm, Sweden. He received his PhD in computer science and electrical engineering at Technische Universität Berlin (TUB) in 2004. His main professional interests are within the area of applied information theory, wireless communications and signal processing. He has published some 35 journal papers and over 100 conference papers on these topics, he is co-author of the monograph "Majorization and Matrix Monotone Functions in Wireless Communications", four book chapters, and he holds three patents on wireless technology. Eduard is Senior-Member of IEEE.
For further information, please send an e-mail to Hans-Jürgen Zepernick