SCHEDULING SCHEMES FOR IMPROVED THROUGHPUT GUARANTEES IN MIMO BROADCAST CHANNELS

Specifying exact throughput guarantees in wireless systems, carrying real-time traffic, is in the interest of both the network operators and the customers. Based on our previous work, we formulate an optimization problem that aims at maximizing the throughput guarantees offered in a MIMO broadcast channel. We also propose two scheduling algorithms that make use of orthonormal random beamforming, and try to fulfill the throughput guarantees promised to all the mobile users. The scheduling algorithms are designed for two different beamforming scenarios. In the first scenario, random beams are used for all the selected users, whereas transmit beamforming is used for the first selected user in the second scenario. We further propose simple and low complexity adaptive scheduling algorithms that perform significantly better than other well-known scheduling algorithms, in terms of the throughput guarantee violation probability.