A UWB Spectrum Estimation Method Based On Compressed Sampling

In recent years,the rapid development of various wireless communication services has made the electromagnetic spectrum resources more strained,so the effective management of spectrum resources is of great significance to both military and civilian applications.As for military,during the communications reconnaissance,the receiver needs to achieve effective signal detection,reception and demodulation in the absence of prior knowledge of communication;As for civilian,users need to quickly find and use spectrum holes to communicate.Limited by constraints of the sampling device,there are mainly two types of receivers commonly used in reconnaissance systems.One is a superheterodyne receiver;the other is a wideband receiver composed of multiple channels.The above receivers are essentially based on the Nyquist sampling principle,when receiving UWB signals,it is inconvenient to store and process the subsequent data.In many wideband non-cooperative recieving situations such as in spectrum sensing,communication reconnaissance and signal interception,due to the sparsity of spectrum,the received signal has been defined as wideband sparse signal.Under such circumstance,this thesis proposed a new method based on the Multicoset sampling scheme and compressed sampling theory,specific hardware implementation is that it composed of time delay wires and commodity ADCs,the delay can be precisely controlled by setting the length of wires on the printed circuit board.Then the delayed signal is sampled by a low rate ADC.Finally using sparse reconstruction algorithm to monitor the spectrum of all narrow-band signals in a few GHz wide frequency bands.The contributions and innovations are summarized as follows:1.Based on the Multicoset sampling scheme and combining with the characteristics of wideband sparse signal and the compressive sensing theory,we model this scheme from the perspective of time domain,and transform it into a classical sparse reconstruction problem.Then using 8 channels with each sampling rate of 50 Msps to monitor the spectrum of all narrow-band signals in 1.5GHz wide frequency bands.2.For the amplitude attenuation and Delay jitter related to time delay wires and commodity ADCs,we proposed a new algorithm based on frequency domain.3.Considering the problem of low computational efficiency and wasted storage space for reconstructing the original signal,we establish a relationship between compressed measurements and their statistical information,directly reconstruct the power and cyclic spectral of the original signal.Then we acheive the modulation recognition and real-time sensing based on the cyclostationary characteristics.4.The current parameter estimation methods are designed for a single modulation type,single signal communication model,we proposed a novel parameter estimation method based on curve fitting.The joint parameter estimation can be realized without separation of multiple signals,simulation results show that our proposed method offers competitive performance.