Sum throughput enhancements in quality of service constrained multiuser MIMO OFDM systems

In many wireless applications, such as video streaming, data transfer or mobile Internet, user satisfaction is directly related to the transmission rates of the wireless channels in the physical layer. If the transmission rate of one user undercuts a certain level, the quality of the application becomes unacceptable. Furthermore network operators are interested in maximizing overall system throughput. However, this aim can usually not be achieved without violating these minimum rate constraints. In this article we therefore consider a practical resource allocation scheme for MIMO OFDM systems that achieves both aims without requiring computationally expensive optimization algorithms. The main part consists of a user classification. Users in one group will only be served with their minimum required rates. The remaining users can exploit the additional system resources more effectively for strong throughput increases and are therefore put in the other group. An iterative application of the proposed scheme enables additional throughput increases and the consideration of maximum transmission rates.