Opportunistic Multiuser Beamforming based on Spatial Signature Matching

While most current researches on opportunistic beamforming assume that users are uniformly distributed around BS, no attention has been paid to address more pratical scenarios where spatial user density is heterogeneous. In this paper, we propose a novel opportunistic beamforming scheme to better exploit the multiuser diversity in case of heterogeneous user density. The key idea is to grant the highest service priority to users in the area with highest spatial user density. It is implemented by an improved selection of the weight vector at each time slot without explicit knowledge of the spatial user density. To address the fairness issue, the joint area-user proportional fair scheduling (JAUPFS) is proposed, which simultaneously guarantees the fairness between areas with different spatial user densities and different users in the same area. Simulations are conducted to demonstrate that our proposed scheme has a better rate performance than that of the conventional opportunistic beamforming.