Fair scheduling and orthogonal linear precoding/decoding in broadcast MIMO systems
Conference: PIMRC 2005 - 16th Annual IEEE International Symposium on Personal Indoor and Mobile Radio Communications
09/11/2005 - 09/14/2005 at Berlin, Germany
Proceedings: PIMRC 2005
Pages: 5Language: englishTyp: PDFPersonal VDE Members are entitled to a 10% discount on this title
Bosisio, R.; Primolevo, G.; Simeone, O.; Spagnolini, U. (Dip. di Elettronica e Informazione, Politecnico di Milano, P.zza L. da Vinci, 32, 20133 Milano, Italy)
In the downlink of a multi-user MIMO system over a fading channel, the base station can assign the available spatial streams to different users by capitalizing on multiuser diversity or enforcing fairness constraints. Assuming linear precoding (beamforming) at the base station, the problem amounts to the joint design of precoding matrices and channel aware scheduling, according to the cross-layer paradigm. In this paper we formulate the joint optimization of scheduling and linear precoding within a physical layer-oriented framework, where the performance metric is the transmission rate. Moreover, we constraint the precoding scheme to ensure interference-free reception of spatial streams (Orthogonal Space Division Multiple Access, OSDMA). Fairness constraints are either inspired by the max-min or the proportional fair criterion. Performance of different schemes is evaluated by numerical simulations allowing to assess the trade-offs between sum-rate (multi-user diversity) and fairness.