Queue-Aware User Scheduling in Multi-User MIMO Systems

The patent segments the user set into multiple subsets based on queue state information (QSI), where only users in specific subsets need to provide channel state information (CSI) feedback. This segmentation allows the system to achieve good throughput performance with reduced feedback overhead by selectively scheduling users rather than requiring feedback from all users.

The patent applies partial action by requiring CSI feedback only from a portion of users (those in selected subsets) rather than all users. The queue-aware subset selection ensures that this partial feedback mechanism still achieves effective throughput performance by focusing feedback collection on users who are more likely to be scheduled based on their queue states.

The patent divides the scheduling decision into two independent stages: first selecting user subsets based on QSI, then scheduling within those subsets using CSI. This segmentation avoids the exponential complexity of jointly optimizing both QSI and CSI, as each stage can be performed separately with polynomial complexity operations.

The patent employs dynamic subset selection where the composition of user subsets changes over time based on queue state variations. This dynamic approach allows the system to adapt to changing traffic conditions and achieve good delay performance without requiring exhaustive search, as the subset selection follows simple rules based on current queue states rather than complex real-time optimization.