Modulation Recognition Of Wireless Communication Signal

In many practical applications of communication, we need to use various means to distinguish the different nature of the signal, without having enough prior knowledge of the case.Using continuous signal receiver to receive and monitor signals in space activities, and even intercepted the information of transmitted signals of great interest,etc. For example, in modern warfare, electronic countermeasures usuallly needs arms unit of the electromagnetic spectrum on the battlefield to monitor closely the activities, in order to steal the enemy's information to conduct electronic intelligence, or suppress the enemy communication, governmental departments need to detect radio statust. Different types of communication signal are often taken under different modulation, the modulation type is an important feature to distinguish between different signals. Modulation refers to automatic recognition without any prior knowledge or prior knowledge in a few cases, the communication received signals after being analysised and processed, ultimately determine the modulation of interested signal, providing various information and parameters for further processing. Modulation recognition is a cognitive radio, war, reconnaissance and communications, electronic repression and confrontation.Anyway,modulation is important for us to research.In this thesis,I analyse the current research and main problems,then give some ideas about how to improve it. The main work of this thesis can be summarized as follows:Firstly, A brief introduction of several most commonly used method of modulation and briefly describes the theory.then a more detail of common characteriscs and signal model.then give the problem of common technology,Secondly, Research on real radio channel.take rayleigh fading channel as example.give two way to solve the problem caused by channel fading.Finally, Research on the modulation recognition of jamming signaland two mixed signals.Give some probably way solving the problem.Then give another newway to solve the recognition of mixed signal.A large number of simulation shows good results.