Cross-Layer Scheduling for Multi-User MIMO Systems
01 January 2006
The increasing demand of wireless services associated with the scarcity of the radio spectrum and the trend to provide end-to-end quality of service (QoS) in emerging and future applications, calls for the design of spectrally efficient systems with QoS support. To fulfill these two requirements of spectral efficiency and QoS provision in the highly dynamic environment of mobile radio requires the collaboration of several layers in the system as well as the use of multiple transmit and receive antennas. In a packet network, one important component to achieve the aforementioned efficiency goals is a properly designed scheduling algorithm. Using an information-theoretic framework, we present an overview of the issues associated with the design of packet scheduling algorithms and review several proposed solutions. The paper focuses on the advantages of a cross-layer approach to the resource allocation problem and identifies the trade-offs associated with the increased signalling needs. The additional degrees of freedom provided by the use of multiple transmit and receive antennas is thoroughly discussed too.