A novel suboptimal SDMA grouping algorithm for multiuser MIMO-OFDMA systems

Wireless communication systems based on multiple input-multiple output (MIMO) in combination with orthogonal frequency division multiple access (OFDMA) and space division multiple access (SDMA) are flexible, spectrally efficient and of high capacity. These systems can allocate frequency, time, and space resources adaptively among mobile stations (MSs). In order to perform an effective resource allocation (RA), MSs must be organized into groups containig MSs with best average sum rate. Since frequency and time resources could be designed orthogonal, the problem of grouping remains only for the space resource. Complexity of the grouping algorithm is also an issue, especially when the number of MSs is high. In this paper, a novel suboptimal grouping algorithm is proposed. A new metric is also introduced to measure the efficiency of a RA strategy.