The Research On The Aerospace Information Network Broadband Multi-access Technology

With the development of aerospace technique, aerospace leading powers are chasing constituting aerospace information network and achieving aerospace information superiority. The basis of aerospace information network is aerospace information transmission network, while the constitution of space-based backbone transmission network and access and interconnection to various platforms is the core. Compared with existing satellite communication systems, the type of the terminal and business as well as the quality of service requirements which supported by the future aerospace information transmission network are more abundant. Future aerospace information transmission support numerous types of platforms, including satellites, missiles, spacecraft, hypersonic aircraft, etc. Different platforms may vary in orbital height, running track and mobility, meanwhile the demand of communication transmission differs among communication transmission platforms, but all those platforms strongly demand high-speed broadband access. Though the existing aerospace measurement and control communication systems support single-site-high-speed and multi-site-low-speed communication, however the multi-site-high-speed access system is not mature. Therefore, to ensure the access terminal can send and receive large volumes of data reliably with high-speed, we need to design a multiple access system for the aerospace information network to provide a certain Qo S guarantee mechanism.Response to those demands, this paper firstly constructs aerospace information network multi-site model based on STK platform which utilizes GEO satellites as access points; then in consideration of typical access platform such as near space platform, missile, and LEO satellite, etc., simulation is carried out concerning access link characteristic including link transmission distance, running speed, and Doppler frequency shift; and provide basis for the design of aerospace information network multi-site access system.Secondly puts forward CPM-FDMA system to realize aerospace information network broadband multi- access according to the characteristic of aerospace information network access link, and analyses the superiority of CPM in power and spectrum efficiency, and further study the performance of CPM-FDMA system.Based on these, response to the non-linear defect of FDMA mechanism, we finally introduce a model of flexible satellite transponder into the system and prospect a simple and highly reliable algorithm of the link resource allocation, which is based on the improved genetic algorithm with adaptive penalty function. The algorithm prospected in this paper optimizes the satellite transponder gain of each subchannel on the one hand which reduce the difference between the carrier powers of the satellite transponder. On the other hand the algorithm improves the nonlinear effects in the high-power amplifier of flexibility transponder by selecting the appropriate operating point Z. The simulation results proved that the performance of the proposed algorithm is superior to the classical algorithms.