Research On Resource Allocation And Scheduling Algorithm Of Multi-beam Broadband Satellite Communication System

Muiti-bear satellite promotes the communication capacity by employing the cellular structure based on the same frequency multiplexing technology.However,it also faces the great challenge due to the large number of terminals,dynamic and various characteristics of satellite communications.Therefore,how to reasonably allocate and manage on-board resources,so as to further improve the utilization rate of on-board resources and ensure the communication quality of users,has very important research significance.In order to solve these problems,this paper studies the power allocation between beams,the time slot allocation and the time slot scheduling of tenninals within beams from the two levels of resource allocation between beams and the resource allocation within beams.In order to realize the rationality of power allocation among beams and improve the efficient utilization of power resources,an optimal power allocation algorithm based on genetic algorithm(GA)was proposed.Considering the interference of beams with the same frequency,an optimal model to minimize the difference of capacity request and the allocated capacity was derived on the constraints of total service within all beams,channel status and delay requests.Solving the optimal model uses GA.Simulation results show that the designed algorithm can achieve the minimum between the requested capacity and the allocated capacity on the condition that the minimal capacity request of each beam should be satisfied,so as to realize the flexible power allocation between beams and meet the capacity requirements of each beam.In order to balance system performance and user service quality,a dynamic slot allocation model maximizing the utility was designed for the time slot allocation within a single beam.An algorithm called cross-layer dynamic time slot allocation was further presented on the basis of optimal model.The presented algorithm constructed a utility function which referred the cross-layer design for communication networks and totally considered parameters of application,data link and physical layer.The aim of our presented algorithm is to achieve the optimal time slot allocation by maximizing the value of constructed utility function.Simulation results show that the presented algorithm promotes the justice of time allocation for various service requests without the loss of throughput,so as to ensure the optimal allocation of time slot resources.In order to ensure the flexibility of multi-user and multi-service access,a hybrid time slot scheduling algorithm which focused on the location distribution of time slot was proposed.Considering the access constraints of MF-TDMA and quality of various service,the scheduling algorithm integrates an improved Reserve Channel with Priority-fit Algorithm and First-fit Decreasing algorithm,among which the improved Reserve Channel with Priority-fit Algorithm is applied for real-time service while First-fit Decreasing algorithm is applied for non-real-time service.Simulation results show that the hybrid time slot scheduling algorithm not only guarantees the quality of various service but also achieves the effective utilization of time slot,so as to realize the effective utilization of time slot resources.