QoS-based multiuser scheduling in MIMO systems

Packet scheduling techniques exploiting multiuser diversity have been proposed in order to improve the throughput of high speed packet systems. However, the use of techniques that take the scheduling decisions based only on the channel conditions, may fail to provide the desired QoS, as the maximum allowable delay is an important parameter, and therefore algorithms aiming at providing QoS should combine QoS related parameters with the channel conditions. In this paper we consider two algorithms that address this issue. One algorithm has been developed D. Avidor et al., (2004) to improve the opportunistic beamforming technique by tying the sequence of radiation patterns with the waiting times of the served mobiles, while the other weights the waiting times and channel reliability to schedule the packets while using beamforming to spatially reuse the radio resources in a CDMA scheme. We show through simulations that such schemes lead to reduced probability of excess delay while keeping a high throughput