Research On Cross-Layer Resource Management Methods In Satellite Communication Networks

With the development of global information technology and network, terrestrial network can not satisfy the people's growing needs of multimedia communications. The efficiently using satellite network for multimedia transmission is an important key solution. As the satellite technology keep on development, satellite network has become the carrier of some new applications, which includes data, E-mail, FTP, Web and so on. So people have put forward a large request for the satellite communication bandwidth resource when its delivery traffic expands. The radio resource management is mainly to ensure the quality of service (QoS) for users under the limited resource. Its basic point is dynamic assigning and adjusting the useable resource for the wireless network. Furthermore it can increase the resource utility as much as possible. The radio resource includes frequency, slot, code and space resources. Through reasonable radio resource management methods, the network can provide satisfied QoS.The traffic QoS needs support of protocol. Traditional radio resource management design method is based on the layered protocol design. This method is usually suitable for the fixed stability network. But satellite network is dynamic and the satellite channel state is variable. Using the layered protocol design will not bring the most optimization performance. For solving above problems, researches proposed the cross-layer design method. This method breaks the wall of the protocol layer. The protocol layer can exchange the information each other to increase the performance and offer the satisfied QoS to users.Based on the latest research, the dissertation makes a deep and systemic research on radio resource management methods based on cross-layer design in satellite network. It includes MAC access scheme, downlink packet scheduling algorithm and bandwidth allocation scheme in satellite network. The dissertation presents some new ideas and design methods. The main contributions are:Firstly, to analysis in the CFDAMA-CR protocol carefully, it focused on the MAC performance degradation problem caused by dynamic satellite channel state. The CFDAMA-CCSI to solve this problem is proposed. The access node and satellite scheduler can change the MAC layer's access scheme in real time based on the channel state. By simulation results, the proposed scheme can increase the delay and throughput performance compared with the other layered design in GEO satellite network.Secondly, the performance of traditional packet scheduling algorithm is studied. It focused on the satellite network which can carrier on different traffic and proposed a cross-layer scheduling algorithm combined utility function. Based on the limitation of the BER and delay, it proposed a suitable cross-layer transmission mode and optimized the overall utility of different traffic through solving the optimization equation. The simulation results proved that cross-layer scheduling scheme can increases the performance for both high and low priority traffics QoS compared with other methodsNext, considering in the bandwidth allocation scheme of the broadband satellite network, it focused on the satellite network which includes the access node carrying voice and data traffics. A bandwidth allocation scheme for the broadband multimedia satellite is proposed. In the condition of the optimization for call blocking probability of voice traffic and TCP throughput, it set up a cost equation on the bandwidth with the variable channel state. By use of the dynamic programming algorithm it solved the cost equation, the gotten results said that the proposed algorithm can increase the TCP throughput performance as well as ensure the voice access.Finally, in order to solve the TCP protocol performance degradation problem in DVB-RCS satellite network, it optimized the TCP performance in the combination of TCP, MAC and PHY layers. In DVB-RCS network, the TCP protocol performance is influenced not only by MAC layer seriously but also by physical layer. Considering the bandwidth request and congestion window evolution together, it solved the TCP performance degradation due to long transmission delay. Based on different channel state, it improved the transmission mode to enhance the TCP throughput performance. Compared with other access schemes, the proposed cross-layer TCP optimization mechanism can increase the channel utilization, throughput and delay performance.