Research On Index Code Scheduling And Resource Allocation In Multicarrier Multicast Wireless Networks

In wireless networks, multicasting of MBMS(Multimedia Broadcast Multicast Service) was designed to provide both broadcast and multicast content distribution services to meet the emerging requirements of multimedia applications for mobile users. OFDM technique has been widely used in broadband wireless systems such as IEEE 802.11 WLANs, 3G-LTE, Wimax, etc. In multicast OFDM networks, the station can transmit packets over multiple subcarriers simultaneously. Wireless channels are subject to fading due to signal attenuation, shadowing and multipath effects, which leads to random failure of packet reception at different receivers. On the other hand, receivers may have diverse demands and channel qualities, so wireless resource should be allocated carefully to different receivers, otherwise it may lead to unfairness issue or the waste of wireless resource.In this paper, we study the problem of packet transmission and resource allocation in multicast OFDM networks, to our knowledge, we are the first to jointly consider the problem of index code construction and the transmission of index codes. Our first attempt is to improve the multicast transmission efficiency to the largest extent by jointly considering the design of index coding and transmission scheduling. To this end, we firstly propose a scheduling algorithm for subcarrier allocation. We then propose a cycle-based coding technique for the multicast index coding problem, and design the corresponding joint multicast subcarrier and index coding allocation scheme. We also transform the problem and design a suboptimal solution.In the study of resource(subcarrier, power) allocation in multicast OFDM networks, we also formulate the multicast resource allocation problem by incorporating with the side information and design corresponding optimization allocation schemes. This problem can also be transformed to the maximum coverage problem, and a greedy algorithm is designed that solve the problem efficiently with guaranteed approximation ratio. Simulation results show that our proposed schemes can provide substantial improvement under various conditions.