Abstract
In a cognitive radio (CR) network, the secondary users (SUs) are allowed to utilize the primary channels (PCs) when they are unoccupied. To avoid collision with the primary users, SUs must sense the PCs before transmitting their signals. Conceptually, the number of available channels sensed by the CR network depends on the length of sensing duration. The tradeoff between the length of sensing duration and the detection performance will affect the throughput of the CR network. In this work, we aim to obtain an optimal number of available PCs in order to maximize the overall system throughput of the SU’s network. In a multi-channel multi-user environment, we also propose a channel allocation algorithm to assign the available channels to inhomogeneous SUs. In this thesis, we also study the problem of throughput maximization for a multi-channel CR network allowing SUs starting their transmissions non-simultaneously. Since the network throughput will be calculated earlier if SUs can transmit signal once a PC is sensed to be available, the transmission order of SUs is an optimization factor. We discuss and compare the simultaneous transmission scheme with the proposed non-simultaneous transmission schemes for throughput maximization in inhomogeneous multi-channel CR networks. Finally, the simulation results not only show that the proposed scheme is feasible but also indicate the transmission order of SUs will be different according to various parameters.