Opportunistic scheduling in wireless communication networks

Wireless spectrum efficiency is becoming increasingly important with the growing demand for wideband wireless services. In this dissertation, we present a unified framework for opportunistic scheduling, which exploits the time-varying nature of the radio environment to increase the overall performance of the system. Our framework enables us to investigate various categories of scheduling problems, differing through their QoS objectives. The QoS objectives studied in this dissertation include two fairness requirements (temporal fairness and utilitarian fairness) and a minimum-performance requirement. We find optimal solutions for these scheduling problems. An attractive feature of these optimal solutions is that they are given in a simple parametric form, hence lending themselves to on-line implementation. We provide algorithms to estimate the parameters in these optimal solutions and describe implementation procedures for each solution. An advantage of opportunistic scheduling is that it can be coupled with other resource management mechanisms to further increase network performance. In this dissertation, we study joint scheduling and power control schemes for intercell interference alleviation. We investigate two different problems in this context. In the first problem, the objective is to minimize the average transmission power, and thus interference to other cells, while maintaining the required data-rate for each user within the cell. In the second problem, the objective is to maximize the net utility (defined as the difference between the value of throughput and the cost of power consumption) with the same data-rate requirements. We establish the optimality of our joint scheduling and power-allocation schemes for these problems, and discuss their properties