Distributed multicast resource allocation in OFDM-based cognitive radio networks

Abstract

In this paper, the resource allocation problem, which aims to maximize the weighted sum rate in orthogonal frequency division multiplexing based (OFDM-based) multi-cell cognitive radio networks (CRNs) with multiple description coding multi-cast (MDCM), is investigated. A two-phase distributed scheme including subcarrier assignment and power allocation is proposed. During subcarrier assignment phase, each cell determines the multicast group (MG) selection for each subcarrier and the set of scheduled cognitive radio users (CRUs) in the selected MG by a proposed heuristic scheme to maximize its weighted sum rate under uniform power distribution assumption. During power allocation, each cell allocates power on subcarriers by a proposed distributed geometric programming (GP) power allocation algorithm. Unlike the existing centralized solutions in the literature, it does not require global network information and each cognitive radio (CR) cell performs its own resource allocation through limited collaboration with other CR cells and primary networks (PNs). Numerical results demonstrate the validity of the proposed resource allocation scheme and the advantages of MDCM over conventional multicast (CM).