Abstract
Multicast is an efficient transmission scheme for the same content to multiple receivers while minimizing networks resource usage. In multicast systems, the transmitter adapts its data rate to the worst channel among all users in the multicast group, so as to guarantee service quality to each user. Applications that can benefit from multicast, such as multimedia streaming and data services, are now being deployed over 3G wireless data networks. A natural question that arises is how to group users in order to maximize the total throughput of multicast systems. In convention, the maximum group size can maximize the system throughput. However, this conclusion is based on one condition of continuous-rate assignment. In practical systems, the assigned data rate on each subchannel must be discrete. Therefore, in this thesis, how to group users or determine the group size under considering discrete-rate assignment is studied. Through theoretical analysis, we prove that the optimal size in a multicast group increases with the increasing transmission power from the base station. Moreover, by the proposed optimal group size, the achieved throughput in multicast systems is maximized. Our analysis is validated through simulations.