Research On The Correlated Imaging In A Rician Fading Channel

In wireless communication,the interference of transmission environment will cause energy loss.The received signal usually has strong randomness and weak strength.The detection of effective signal is still difficult.In the remote space communication,it is very important to ensure the stability of space information transmission.As a new non local imaging method,correlation imaging has good spatial resolution ability and resistance to environmental interference,which shows advantages in atmospheric interference and low light environment.The Rician fading channel is a typical fading channel,which describes the environment with direct path and infinite multi-path scattering sources.And the channel quality can be directly reflected by the estimation of the Rician factor.The basic theory of correlation imaging system in a Rician fading channel is studied,and the influence on the imaging quality is analyzed in detail.1.A theoretical model of correlation imaging in a Rician fading channel with additive random noise is given,and the process of correlation imaging is qualitatively analyzed by using the point spread function.Then,the influence of path loss and the Rician distribution on the imaging quality is quantitatively analyzed by calculating the peak signal-to-noise ratio and resolution.The results show that with the increase of transmission distance or the decrease of Rician factor,the imaging quality of the target object decreases gradually.In addition,the results of traditional uncorrelated imaging and correlated imaging are compared under the same conditions,which shows that correlation imaging has better imaging quality and longer effective transmission distance.This research provides reference and guidance for spatial information transmission in a Rician fading channel.2.The influence of coding characteristics of imaging target is also studied.Firstly,according to the coding requirements,an object with a code type feature is defined.Then,two typical code types(return-to-zero code and non-return-to-zero code)are selected as our imaging targets,and numerical simulation is carried out.By studying the influence of the Rician factor on the shape of signal,it is found that the return-to-zero code are more suitable for transmission in a Rician fading channel;by comparing the performance of two types of code objects in a remote transmission,the results show that return-to-zero objects have better performance.It is noted that the duty cycle parameters directly reflect the difference between the two types of codes.Therefore,we set the duty cycle parameters of the imaging target according to the coding requirements,and discusses which duty cycle value is the most suitable in detail.