Research On The Channel Assignment Scheme For LEO Constellation Satellite Communication System

As an important part of a global seamless personal communication, the Low-Earth Orbit(LEO) constellation communication system is developing in many aspects of correlative technique. Wireless resource management is an important researching field, of which a main technique channel assignment is.The moving character of the constellation satellite decides that the users handoff frequently among the spot beams of the satellites. So it's necessary to find a more adaptable channel assignment scheme than the one used in terrestrial cellular networks to decrease the handoff failure probability and the new calling blocking probability, in order to improve Quality of Service. The proposed schemes just consider either the less aspects of Quality of Service or only real-time traffic. Therefore, it's significant to research the channel assignment scheme which is trade-off between the new calling and the handoff calling performance and adaptable in Multi-carrier LEO Constellation Communication System.Firstly, we described the concept of resource management and channel assignment in LEO Constellation Communication System, summarized totally the classical algorithms to solve the problem of the channel assignment. After analyzing the mobile model and the correlative parameters, QoS performance evaluation of the these schemes had been carried out by simulations. The characters of the schemes were pointed out.Then, we introduced a classical schemes called time-based channel reservation algorithm. Based on this scheme we proposed a Preempting Reserved Channel Mechanism based on TCRA. According to the QoS this mechanism determine a value with which compare the time value when all the channels are reserved and determine whether new calling is accepted. The simulation results show that, compared to TCRA, the proposed strategy can effectively improve the new call blocking, and at the same time provide the network with better QoS guarantees.At last, based on the guaranteed handover scheme, we proposed an insufficiently guaranteed handover scheme, which assigns the channels for calling in the time less than a can decrease the new call blocking probability and improve the cannel available prioritization. Base on the scheme of the voice traffic, we extended to the multi-carried and proposed the method to carry out the scheme. The simulation results show the feasibility and availability of the proposed scheme with respective degree based on different traffic load.