Research On Amplitude Probability Distribution Model Of Radio Disturbance And The Algorithm For Interfering Effect On Digital Communication Systems

The existing limit of emission is quasi-peak (QP) value which is made to protect analog communication systems. QP value reflects human's auditory perception properties for analog voice signals. As digital communication technology has been developed rapidly, various kinds of communication systems are used, which makes our electromagnetic environment become more and more complex. Therefore, the new limits of electromagnetic emission are needed. However, the performance of digital communication systems is evaluated by error probability, so QP value cannot be used for evaluating the performance of digital communication systems. Therefore, statistical measuring methods are suggested to strengthen the weakness of QP value.Statistical measuring methods, such as amplitude probability distribution (APD), can be preferably used for describing the statistical properties of random interference and the interference models can be established easily. What's more, the research object of statistical measuring methods is the intermediate frequency output envelope before detector, so the statistical results are not affected by charge-discharge time constant of dector. This dissertation studies on the the algorithm for evaluating the error probability of digital communication systems by using APD statistical results of disturbance. And then, we give some simulating and testing results to validate the feasibility of the algorithm. Finally, we discuss the methods of developing APD limits based on the algorithm. The work of this dissertation is supported by the 863 National High Technology Research and Development Program of China "research on the EMC of cognitive radio communication systems" and the project of State Raido Monitoring Center "APD measuring equipment of electromagnetic disturbance".Innovation and creative points of this dissertation are as follows:1. The novel application of APD statistical measurement in radio equipments testing is shown based on the APD properties. APD measuring method can simplify some testing steps and improve the tesing accuracy (Chaper 2). 2. On the basis of analyzing the shortages of traditional derivation method of error probability, a novel algorithm for evaluating the error probability of digital communication systems is proposed. The algorithm is based on the APD statistical property of disturbance, and it also includes the phase factor of interfering signals. In order to enforce the common use of the algorithm, we assume that the phase distribution is uniformed, and realize the algorithm on computer by discrete treatment. Meanwhile, we compare the error probability calculating by algorithm with the one getting from simulation and explain the availability of the algorithm (Chapter 3 and Chapter 4).3. This dissertation applies the algorithem to analyze the interfering effection on actual digital communication systems, especially for analyzing the performance of frequency hopping communication systems. We present a new method of analyzing performance of frequency hopping communication system by using the APD statistical results in the working frequency band and the evaluating algorithm (Chapter 5).4. We present the relationship between BER limit and APD limit with the way to make APD limit of disturbance based on the algorithm. The average APD limit and maximum APD limit are firstly presented interiorly and provide reference for making APD limits (Chapter 6).The dissertation consists of 7 chapters, including 91 figures,18 tables, and 127 references.