Optimum scheduling for smart antenna systems in Rayleigh fading channel

Optimum and suboptimum scheduling schemes are proposed in the uplink of array antenna systems. We assume that once a user is permitted to transmit the data, the user transmits the data using the maximum power and adjusts the transmission bit rate so that the received SINR remains fixed. In this system model, we consider an optimization problem: how many and which users should be selected to transmit their data at a time in order to maximize the throughput? Based on the analysis on the complexity of the optimum scheme, we propose another optimum scheme having reduced complexity. In circular arrays, numerical results suggest that the maximum number of simultaneously transmitting users can be limited at the expense of small throughput penalty. Motivated by this result, we propose a suboptimum scheme to reduce the complexity further. Numerical results show that the suboptimum scheme provides almost the same performance as the optimum scheme with a dramatic decrease in the complexity.