Relay Location And Relay Selection In Cooperative Multicast Networks

With the rapid development of mobile communication and the rapid popularization of intelligent terminal with high performance, People are interested in multimedia services and show a strong desire to buy them. The traditional communication has been difficult to meet the demand of a large number of mobile users for multimedia services, so the multicast transmission will inevitably become the trend of wireless communication. In order to meet the demand of high-speed multimedia services, researchers put forward cooperative multicast network, Terminal cooperative multicast technology is a new research direction,because it can slove the bottleneck problem and improve the multicast throughput.In the cooperative multicast network, it is necessary to consider how to decide the number of relays and how to locate the relay to improve the performance of the system. The number of relay and the location of the relay node will greatly affect the capacity and the power consumption of the system. Nowadays people spend more and more time on the mobile terminal equipment, while capacity of the battery is a fixed value. So it is necessary to reduce the power consumption of the mobile devices. At the same time, the excessive energy consumption may cause more pollution, so green and efficient wireless communication has become very hot. The research content of this paper mainly includes:(1) Firstly, the impact of the relay node and the primary users location on power allocation and system throughout was investigated. In a cognitive radio network consisting of two multicast groups and a pair of primary users, the impact of the relay node and the primary users location on power allocation and system throughout was analyzed based on amplify-forward and decode-forward. The result shows that the locations of relay node and PU are crucial to the system performance and the performance of the optimal power allocation(OPA) scheme and equal power allocation(EPA) scheme was compared.(2) The relay selection scheme was studied for cooperative multicast network. Consider the same frequency resource, A new transmission mechanism called direct and relay-aided transmissions based on inter group cooperation was proposed for the cooperative multicast network. In the transmission mechanism, because of the two multicast group using same frequency resource, a multicast group in the second phase of the communication will generate interference to the other multicast group. So we put forward a relay selection scheme based on the reduction of interference. Then the proposed relay node selection scheme is analyzed by the angle of probability. The result shows the scheme of reducing interference to another multicast group can reduce the number of relays, as well as ensure the system throughput. We know that reducing relay number means the lower power consumption, so the scheme can effectively save the power consumption of the terminal devices.