Research On Statistical Properties For Frequency-nonselective Channels In Mobile Fading Channels

With the development of the society, people's needs for communication are increasing, and demands for communication quality are also more and more high. Especially since the beginning of the 21st century, mobile communication has been greatly developed, and the widely use of all kinds of new mobile communication technology makes the study about the wireless channel a classical subject. The wireless channel is the transmission media for mobile communication, all the information are transmitted in this channel. The performance of wireless channel will affect the quality of people's communication directly, in order to transmit high-quality, large-capacity useful information with limited spectrum resources as much as possible, and the characteristics of wireless channel clearly and their impacts on information transmission must be known. The Frequency-nonselective Channel is the most common wireless channel. In this paper, its statistical characteristics are studied in detail.The research background and signification of this subject is introduced briefly at first, and the history and the trend of Mobile communication is summarized. The basic concept and characteristic of Mobile fading channels are introduced, theory of fading channels, i.e., the multipath propagation and the Doppler Effect is analyzed, and the sort of channels and the basic method for studying Mobile fading channels are introduced roundly, this is the basis for simulation and studying of radio channels. The reference model of Frequency-nonselective Channels is modeled which is discussed based on the Rayleigh and Rich distribution for described Small scale fading, and the Suzki distribution and tow kind familiar Doppler power spectrum density—Jakes and Gaussi power spectrum density are introduced briefly, the first-order and second-order statistical properties is analyzed weightily. The simulation model of Frequency-nonselective Channels which is modeled by Rice method includes Rice, Rayleigh and Suzki simulation models. The Method of Equal Distance (MED), Monte Carlo Method (MCM), and Jakes method (JM) are introduced emphatically. These three methods are used in Jakes power spectrum density to obtain the parameters of simulation models. The first-order statistical properties, including correlative statistical properties and ergodicity, are analyzed in detail, and based on the computer simulation and the comparison analysis; three conditions which measure up the effective simulation model are obtained too. The conclusion is meaningful to design a new channel simulation model. And then an ideal simulation model is chosen, the Probability Density Function of the Amplitude and the Phase and the Level-Crossing Rate and Average Duration of Fades of this model are simulated by computer. Finally, the conclusion is obtained by summarizing this paper, and what is the direction of this subject has been known.