Multicast Recipient Maximization in IEEE 802.16j WiMAX Relay Networks

In this paper, we propose a resource-allocation scheme for multicast service in downlink transmission for IEEE 802.16j WiMAX relay networks. Most existing algorithms try to minimize the total energy of a multicast tree. In contrast, we address the multicast recipient maximization (MRM) problem, which maximizes the total number of recipients with the given budget by adjusting the distribution of the allocated resource between the base station and the relay nodes. We prove that MRM is NP-complete and propose a polynomial-time scheme called dynamic station selection (DSS) to solve the problem based on the proposed auxiliary graph. Based on the provided lemmas, which serve as important guidelines for solving similar problems, we show that our heuristic algorithm has polynomial-time complexity and prove that its performance is bound to the optimum. The results of simulations demonstrate that, given different amounts of resource and variable channel conditions, the performance of DSS is always close to the optimum. Moreover, DSS more efficiently utilizes resources as the node density increases, resulting in more efficient resource allocation.