Research On The Design Of Integrated Signal For Radar And Communication Based On OFDM

In the past, wireless applications such as radar, communication and EW were usually individually and independently with reference to the operation of transceivers, and have independently transceivers and signal processors for each one. This has resulted in a series of questions such as limited availability of spectral resource, incompatibility of the electromagnet, the huge scale, lack of agility, the interference between devises and so on. With the development of current technologies, radio frequency front-end architectures in radar and wireless communication have become more and more similar. On one hand, an increasing number of functions, traditionally realized by hardware components, are being replaced by digital signal processing. On the other hand, the carrier frequency used for communication systems, have shifted to the microwave regime and have become of the same order of magnitude as those traditionally used for radar applications. Hence, a joint radio-frequency hardware platform for communication and radar applications could easily be realized with today's technology. Such a kind of platform would offer unique possibilities for novel system concepts and applications. Even more important, by using a joint waveform for both applications, the occupied spectrum would be used very efficient and both applications could be operated simultaneously, which would help to overcome the limited availability of spectral resource.This thesis deals with the design of the sharing signals, which are suited for the applications of the integrated system of radar and communication simultaneously. Firstly, this thesis introduces the current research at home and abroad, gives a conclusion of the current theory research briefly, and analysis the existed critical obstacles such as limited availability of spectral resource and low data rate. Then, based on the analysis of the difference and the similarity of radar system and communication system, the coherence of the two systems was attested by researching the unification of the communication equation and the radar equation, proving that the integrated system is feasible. Seven hardware combination forms of radar and communication are investigated, the considerations and requirements of waveform design is analyzed as well. OFDM signals are widely used in radar and communication applications, this thesis focus on the design of the integrated signal for radar and communication based on OFDM, meanwhile the signal processing technologies used for the OFDM radar signal are investigated through different aspects,including analysis of processing output for single OFDM chip, coherent integration of train of OFDM chips, solving Doppler ambiguity, etc. Then a joint estimation approach for target's range and velocity based on beam scanning is proposed, the effect of modulated communication information on the ambiguity function of the integrated signal is studied through computer simulation, validating that the proposed approach is feasible. Also its communication performance is investigated. Meanwhile a joint estimation approach for target's range and velocity based on compression sensing is researched, so as to jointly estimate the range and the velocity of the potential target with high resolution. Simulation results demonstrate the feasibility of this algorithm.