The Research Of Key Technologies On Military Cognitive Radio Communication System

Since Doctor Mitola first proposed the concept of specific knowledge of Cognitive Radio in1999, the international and domestic institutions in the related fields have had lots wide-ranging research work about Cognitive Radio, and they have made some remarkable achievements on the theory, schemas, hardware facilities, software realization and protocol mechanisms of Cognitive Radio. However, the application of the research result are also face various technical challenges.This paper introduced Military Cognitive Radio on the base of presenting Cognitive Radio first. Military Cognitive Radio is a kind of Cognitive Radio technology which can cognize electromagnetic environmental of battlefield and have a real-time adjusts to the equipments’internal configuration by means of estimating the battlefield environment. Thus it can adapt the changes of the outside battlefield environment.Military Cognitive Radio if used chiefly for solving the bad electromagnetic environmental problem. It is used to guarantee the reliability of communication, enhance the Spectrum Management efficiency and strengthen the anti-jamming capability of communication system. At present, worldwide research institutions, organization for standardization, industry and the military have carried on the research of key technology in Cognitive Radio. And the research in Cognitive Radio technology of the military is marked by the next generation communication program which is kicked off by DARPA. This plan use Cognitive Radio technology as a key point, keep developing Cognitive Radio practical standard and dynamic spectrum management standard in mind and use the Cognitive Radio to make full utilization of information from space, time and frequency domains to provide strong support for the military operations. Data-link is a general information processing system which can process, exchange, distribute information, it links command-center, combat force and weapon platform. As it is, Data-link receives widely attention in the modernization of national defense communications around the world. China’s develop in this field starts late, Link16tactical Data-Link system plays a positive reference for the development of China’s tactical Data-Link and construction of weapon’s information.After introduce the technical feature of Data-link, this article demonstrated practicability to construct military cognitive wireless communication system based on Data-link. the paper embodies the interference spectrum sensing and spectrum reconstructing in complex electromagnetic environment combined with the system feature of military Cognitive-Radio. The major work and innovation results are as follows:1) Spectrum sensing is the base of achieving Cognitive-Radio system, spectrum sensing in complex electromagnetic environment is especially important to military cognitive wireless communication system. This paper introduces the characteristics of various kinds of interference, analysis the spectrum characteristics of frequency hopping communication system combined with the Data-link feature of frequency hopping and multiple network, identifies the best time to sense, and with time-frequency dual-domain windowing and adaptive energy threshold detection method, this paper proposes a spectrum sensing method which can identify a variety of interference model in complex electromagnetic environment, so as to provide the basis to protect military cognitive-radio system’s available spectrum resources.2) The reliability of the node and the network is the key in the research of data link communication. Based on the introduction of cognitive radio communication system of military network characteristics and the basic function of network nodes, this paper analysis the calculation method of node connectivity and the network nodes reliability algorithm which based on the node connectivity, and put forward network reliability weight assessment method through the responsibility of weighted sure, which determine the basis for the reconstruction of the network spectrum. Combining the characteristics of data link system, the paper propose a implementation of adaptive waveform and spectrum reconstruction, and design communication protocols supported these function, based on which make sure to upgrade system resistance to malicious interference ability in the basis of rapid perception of spectrum interference.3) In military telecommunication field, the distributed simulation has become the development direction of the computer simulation field. Based on the characteristics of the data link network, the module analysis in the ber of the data link node, node connectivity and the time buttress distribution, and the specific requirements of the real-time simulation in the engineering application, this paper puts forward a kind of system level cognitive wireless communication solution, and gives a analyze about the real-time performance of the data transmission in the real-time simulation system in a given model. Also a hardware platform for the simulation system is designed and the main Technical indicators of the simulation system are tested.4) In the paper, on the basis of the theory and application model of the cognitive radio, a Cognitive radio communication terminal hardware platform with radio spectrum perception function has been designed, which could solve the key technical problems of spectrum perception, spectrum reconstruction, high frequency hopping and network synchronization. And all of the research results are verified.