Downlink Scheduling in Multiuser MIMO systems
Event details
| Date | 25.06.2010 |
| Hour | 15:15 |
| Speaker | Prof. Giuseppe Caire, University of Southern California |
| Location | |
| Category | Conferences - Seminars |
High-Speed Data-Oriented donwlink has been included in current 3G wireless standards in various similar forms (e.g., 1xEv-Do for CDMA2000 and HSDPA for 3GPP-WCDMA). These schemes make use of opportunistic scheduling that take advantage of instantaneous channel state information in order to allocate the user to the time-frequency slots with the most favorable channel conditions, subject to some ``fairness'' criterion. For delay-tolerant data traffic, opportunistic scheduling provides a significant throughput improvement with respect to conventional CDMA or TDMA/FDMA with fixed round-robin channel assignment. In the pursuit of even higher data rates, the next generation of wireless systems will make widespread use of multiuser multiple antennas (MU-MIMO) techniques. In this talk, we review the principles of MU-MIMO dowlink schemes (MIMO Gaussian broadcast channel), we discuss the challenges related to providing reliable channel state information at the transmitter(s), and to the presence of unpredictable inter-cell interference due to independent uncoordinated operations in neighboring cells, and provide a comprehensive and general framework to solve the opportunistic downlink scheduling problem that takes into account these non-ideal conditions. The proposed approach builds on a general stochastic network optimization framework based on Liapunov queue stability and Liapunov drift. Effects such as non-perfect channel state information and unknown instantaneous interference power levels from adjacent cells are included, and computationally efficient near-optimal implementation are discussed. Finally, we will present an analysis method that combines results from large random matrices and convex optimization, and is able to characterize semi-analytically the system performance under opportunistic scheduling and arbitrary fairness criteria.
Prof. Caire's homepage
Practical information
- General public
- Free