  Fifth generation cellular systems support a broad range of services,
including mobile broadband, critical and massive Internet of Things and are
used in a variety of scenarios. In many of these scenarios, the main challenge
is maintaining high throughput and ensuring proper quality of service (QoS) in
irregular topologies. In multiple input multiple output systems, this challenge
translates to designing linear transmit and receive beamformers that maximize
the system throughput and manage QoS constraints. In this paper, we argue that
this basic design task in 5G and beyond systems must be extended such that
beamforming design and user scheduling are managed jointly. Specifically, we
propose a fully decentralized joint beamforming design and user scheduling
algorithm that manages QoS. A novel feature of this scheme is its ability to
reduce the initial rate requirements in case of infeasibility. By means of
simulations that model contemporary 5G scenarios, we show that the proposed
decentralized scheme outperforms benchmarking algorithms that do not support
minimum rate requirements and previously proposed algorithms that support QoS
requirements.
