WLC01-2: Resource Allocation and Scheduling for Multiuser MIMO Systems: A Beamforming-Based Strategy

A resource allocation policy using transmit Beam- forming is proposed for the downlink of multiuser systems. Users to be selected for transmission in a given time slot are examined from groups of users to which the proposed algorithm determines the resources to be allocated in terms of antennas and power. The transmit beam-vectors are computed according to a zero-forcing criterion. Users are selected from different groups so as to achieve a desired balance between maximizing throughput and achieving a high degree of fairness among groups of users as well as between users within a group. Such grouping allows the proposed algorithm to make full usage of the resources and to dynamically allocate these while avoiding the complexity of the NP-complete resource reservation and users´ scheduling. Computational complexity is reduced by first estimating the resources to be allocated to the groups of users and then distributing these fairly among the selected users in each group. Such an approach allows the base station to assign its antenna and power resources to groups of users for which transmission would alleviate the interference that would result in neighboring cells, or to direct the resources toward overloaded regions in the cell. Simulation results and comparisons show that the proposed dynamic resource allocation strategy achieves multiuser diversity and a high efficiency in terms controlling the tradeoff between throughput and fairness.