Achievable Degree of Freedom on K-User Y Channels with Heterogeneous Messages

In this letter, we introduce a new system model for a multi-way communication where multiple users exchange information with each other by sharing an intermediate relay with multiple antennas. Particularly, we focus on the system where each user intends to send multiple unicast messages for dedicated users and a single multicast message for a group of users. We refer to this system as a K-user MIMO Y channel with heterogenous messages. For this channel, we propose a new cooperative beamforming method and study an achievable degree of freedom (DOF) using this scheme.