| English Abstract: | Geosynchronous satellite mobile communication system is a system which complements communication between different terminals by geostationary communication satellites, it provides a large span of communications service for users, which is the expansion and extension of terrestrial cellular mobile communication system. Efficient and accurate handover algorithm is one of the keys ensuring quality of service and improving network performance. Different mobile terminals have different types of movement pattern, when the terminal moves between the beams, handover request will be generated in order to maintain continuous communication. The traditional handover algorithms are mainly targeted at the low speed terminals, and the handover decision parameter considering is single, not suitable for geosynchronous satellite mobile communication system. In this paper, we’ll do some further research on the handover algorithm in geosynchronous satellite mobile communication system based on the two-way selection. In the multi-beam GEO satellite communication system, power allocation plays a key role for handover. On one hand, from the electromagnetic radiation characteristics, we know that transmission power decides the receive signal strength, indirectly effecting the result of handover decision. On the other hand, from Shannon Theorem, we know that transmission power affects system capacity of one spot beam, if the value is too small, the handover request to this beam may be rejected, effecting handover result. Thus, we’ll do some research on the power allocation of multiple beam, and propose an optimized power allocation algorithm. Considering total power limitation, communication link quality, minimum request and antenna size affection, we’ll establish and optimize the power allocation objective function, solve the problem based on beam priority and the balance of maximum system capacity and user traffic. Simulation results show that compared with traditional algorithms, the optimized power allocation algorithm in this paper could balance the various system performance quotas, the algorithm is more flexible with higher power utilization, the matching degree between power and traffic is higher. After considering the above system problem, we will propose a dynamic handover algorithm orienting the network revenue. First, by analyzing the various handover factors with great importance, especially the terminal velocity, we can improve the shortcomings in traditional algorithms. Then, the algorithm sets factor weights based on different traffic types. Finally, taking into account that handover is a two-way choice process, the optimization algorithm is divided into two steps. The first steps is the ranks of candidate networks according to user demand, in this step, the users dynamically score the network based on traffic characteristics, choose the best network sequence, forming a handover request. The second step is handover decision according to network revenue, in this step, the algorithm employs dynamic programming for maximizing network revenue to obtain the final decision for request. Simulation results show that compared with traditional algorithms, this algorithm could satisfy user demand and network revenue with a high handover success rate. |
