Research Of Doppler Frequency Shift In Interference Cancellation Repeater

In the3G generation, the QOS of wireless coverage from subscribers is increasedrapidly with the rapid development of mobile communication industry. Repeater which is akind of relay equipment in wireless communication transmission,plays a important role inwireless network coverage. However, the feature of traditional repeater which makesrepeater transmit between the same frequency, limits the application of repeater. With theimprovement of digital signal processing technology, Adaptive interference cancellationtechnology makes good performance in repeater products, ICS repeater is the bestrepresentative. The digital repeater is more suitable than the analog repeater in therequirements such as multiple frequencies、multiple systems、broadband. The digitalrepeater with ICS can reduce project installation costs greatly and improve the reliability ofequipment.There is also some problem in the applications of ICS repeater. The complexity of thewireless environment limit the ICS repeater performance. In the project applications, Theaffect from wireless environment mainly comes from multipath feedback signal andfrequency expansion caused by Doppler frequency shift, which increases the difficulty ofelimination.This paper mainly discusses the Doppler frequency shift in the application of ICSrepeater. In the first chapter, I have introduced the applications of ICS repeater to give thetheory background. In the second chapter, I have introduced the characteristics of wirelesschannel and focused on analysis of Doppler phenomenon and its impact on wirelesscommunications; In the third chapter I,I have introduced the adaptive interferencecancellation technology and several interference cancellation algorithm which aregenerally used, and then introduced the theory of ICS system, at the last explained thepractical applications of ICS repeater. In the fourth chapter I have introduced the impact onthe applications of ICS repeater which comes from the Doppler shift; and given the program for the Doppler shift estimation and compensation which is suitable for ICSrepeater and based on the research progress of Doppler shift estimation and compensation.fourth chapter introduces the current the research progress of ICS repeater. The finalchapter is for summarizes and prospects.