| The development of wireless communication technology provides a much more efficient and convenient life for people,but the demand for spectrum resources of the communication system are increasing.Spectrum sensing technology based on cognitive radio technology can effectively solve the problem that distributable spectrum resources are insufficient and spectrum resources are utilization.The wideband spectrum sensing technology which can be more flexibly searching for the idle spectrum band for the secondary users is paid more and more attention.However,restricted to the constraint that traditional Nyquist sampling theory needs two times the highest frequency to acquire sampling values,resulting in the wideband spectrum detection hardware implementation costly.The development of compressed sensing theory and the raise of analogy-to-information conversion technology provides a new way for direct wideband spectrum detection application from theory to practice,and it has important significance for breaking through broadband perception bottleneck.So this paper depth study on this issue about the analogy-to-information conversion technology based on compressed sensing and its application in the spectrum detection technology.1.Illustrates the research status and basic knowledge of both the spectrum sensing technology and the compressed sensing theory,focuses on the mode of the direct compressed sampling for analog signal,and following the research ideas of the theory of compressed sensing,describes in detail the analogy-to-information compressed sampling model for signal acquisition,the sparse representation process,the measurement matrix forming process and the using reconstruction algorithm reconstructed process,at last detailed analysis of the theory support for broadband spectrum sensing based on compressed sampling.2.Study on the conversion mechanism of the analog sparse signal to information based on compressed sensing theory in detail.First of all,study on RD-AIC that is widely application and development of mature,and simulate the actual signal compression sampling process;then research of RMPI-AIC,and for RMPI-AIC in need a large number of information collection,will result in the system the more parallel accesses and higher hardware complexity.Concerning this issue,detailed study S-AIC which can segmented sample analog signal.This analogy-to-information conversion expands practical sampling measurements through position transformation,equivalently construct new measurementmatrix by reconstructing the original signal;meanwhile according to the mechanism we propose combination transform methods for measurement matrix further expansion,in order to improve the reconfiguration capability of compressed sampling signal.In the end,by the theory analysis and simulation proof,demonstrate that in the same actual sampling parallel approach conditions,increasing the reconstruction matrix size for signal reconstruction,which not only saves the cost of hardware parallel branch,but also improves signal recovery effect.3.Propose a wideband spectrum detection method based on S-AIC.By combining S-AIC mechanism and the power spectrum detection technology,realize the low sampling rate and the low hardware cost of reliable wideband spectrum sensing.Verify the feasibility of S-AIC wideband spectrum detection,and simulate comparison with traditional AIC spectrum detection respectively in different conditions,study these conditions of influence degree on S-AIC of reconstruction performance.Final certificate S-AIC form of the spectrum detection mechanism not only can be good for spectrum sensing,and the detection ability is better than the traditional AIC in the same parallel branch conditions. |
