On satellite optical communication and microwave communication conversion technology - optical commu - News - Business News

Summary satellite laser communication to solve the inter-satellite communication "bottleneck" in the best way. Introduction of satellite optical communication network and microwave communication networks and network background and significance, analysis of satellite optical communication and microwave communication with each other conversion methods. Keywords space optical communication modulation microwave communication1, Introduction With the explosive growth of information flows, the current to the carrier's space satellite microwave communications technology gradually exposed the weaknesses of its own, that as the communication data rates have increased, as traditional means of microwave began to close to its maximum transfer rate bottleneck theory. In this context, it is natural to look to transfer to the laser signal with the optical communications, laser communications expect to rely on high data transfer rate to solve the problem. Satellite optical communication i s a new means of space communication. Use of artificial earth satellites as relay stations transmit laser signal can be achieved between multiple spacecraft and between spacecraft and earth station communications. The high transfer rate, high security and reliability, confidentiality and strong, terminal devices are small, light weight, low power consumption perseverance attracted national experts to explore the [1-4]. Space laser communication system in the structure should have an interface with the microwave communications. There is no one country has established space laser communication link, and therefore the satellite microwave communication and optical communications, few studies of mutual conversion process. In the field of optical communication has been a breakthrough, the successful realization of the satellite - terrestrial, satellite - satellite optical communication between tests in recent years is expected to enter the practical application [5-6]. Therefore, t he space optical communications and microwave communications interconnection is a problem to be solved. 2, laser inter-satellite links Laser inter-satellite links include synchronous satellite communication link between, synchronous orbit and low orbit satellite communication link between China and LEO satellite communications links between satellites and ground stations and communication between link. Based on consideration of the space environment, satellite and ground-based microwave link can only. Therefore, in order to meet the demanding star power, volume and complexity of the request, must study the satellite communications and microwave communications polish the mutual conversion technology. In addition, the existing satellite network using microwave technology, in order for satellite optical communication to optimize their effectiveness, the need to address the traditional satellite communications and satellite communications, optical networking technology, therefor e, necessary to conduct in space optical communications and microwave communications interchangeable. 3, satellite communications and microwave communications optical conversion methodFor most satellites, it is both microwave and optical communication link conversion node, is also a satellite routing optical network switching nodes, shown in Figure 1. On the one hand, when the node up / down link, the satellite must complete the microwave / optical and optical / microwave interchangeable. On the other hand, routing is determined by the middle of the satellite onboard processors, according to the dynamic routing table lookup to complete, so that the packet needs to go through complex demultiplexing, demodulation process and routing the exchange of such treatment. The relay satellite and the LEO satellite (GEO-LEO) relay link between the laser, the need to send back to the ground to LEO LEO high-speed data initially modulated laser communication terminals to the relay satellit e complicated by the GEO laser communication terminal for receiving, processing obtained by the regeneration of the baseband demodulation signal, then microwave for QPSK modulation, the frequency to Ka-band, Ka-band satellite ground line via the link sent to ground stations. LEO sent to the first floor to the low-speed data, the spread spectrum, BPSK modulated, the ground line from the Ka-band satellite link sent to the relay satellite, GEO received baseband demodulation signal regeneration processing, enter the GEO optical laser communication terminals prepared and sent to LEO laser communication terminal. This microwave communication and optical communication method exists mutual conversion process complex, cumbersome equipment and network delay to increase the volume and other shortcomings, can not meet the requirements of the satellite payload. [7], according to satellite network bandwidth (the next generation of optical satellite network as much as 10Gb / s), relatively few number of nodes and network connectivity is relatively low and so on, presents a puzzling baseband data No header is detected using directly modulated laser microwave microwave communication and optical communication with each other conversion programs. System, the basic principle is: the ground-launched processor (TP) under the IP header information to the to go to the target satellite as a standard, a "satellite flow" of the division, the formation of multiple microwave subcarrier channel (f1, f2, ..., fn ), here for subcarrier frequencies fi to its satellite network, said routing information;

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