Traffic-Aware Joint Allocation of Uplink Control and Communication Channels in Multicast Systems

In multicast wireless access systems such as a trunked mobile radio system, channel allocation is performed based on multicast groups instead of radio units. Thus, in these systems, the call source units are these groups, which we also call the users. In a practical system, these users are finite in number, and each user or group may consist of many radio units. In this paper, we discuss the coupling of uplink control and communication segments (layers) of such finite source systems, in which the performance of one layer directly affects that of the other. The conventional studies model these system segments separately and, thus, are unable to capture the coupling issues in networks with the finite sources' constraint. We first propose a novel model that incorporates this coupling by jointly quantifying both the collision loss at the control layer and congestion loss at the communication layer. Under our proposed framework, we further optimize the number of uplink control and communication channels to minimize the joint total loss rate given a constraint on the total number of available channels. In addition, we demonstrate the capability of our proposed model in estimating the invisible actual traffic load and provide guidelines for developing an algorithm for the traffic-aware allocation of channels, based on the proposed model.