Rateless code in QoS-based multiuser scheduling for MIMO systems

This paper proposes a new multiuser scheduling scheme for MIMO system that can simultaneously support various QoS requirements of different user groups while satisfying fairness among the same user group in a RRS (Round Robin Scheme) manner. To guarantee high transmission reliability, a cross-layer scheme is adopted by combing spatial diversity in the physical layer and systematic Raptor code in the MAC layer. The delay-sensitive users are scheduled with higher priority. When only one user is chosen at each time slot, spatial diversity is adopted to guarantee a low BER. Furthermore, if N_t users are chosen at each time slot, AA-RRS (Antenna Assisted Round Robin Scheme) is adopted to improve the system capacity, which is brought by the inherent multiuser diversity of the MIMO system. Simulation results demonstrate that the proposed cross-layer scheduling scheme can guarantee a much higher reliability than spatial diversity transmission with only a small increase of delay.