A Study On The Key Technique Of Smart CDMA Repeater

Recently, with the swift development of the communication technology, especially the cellular mobile communication technology, the subscribers of mobile communication are rapidly increasing. Based on the statistics provided by Information Industry Ministry, in our country it is show that there were totally 13,329,000 mobile subscribers in1997, but there were already 250,000,000 users in 2003. The increasing of the users makes investment in mobile communication increased greatly.As it is low investment, low running cost, relatively short building period and good network quality, and thus the repeater which is a kind of useful radio signal transmission and enlarging facility is used widely to extend and cover the mobile communication blind area and to enlarge the base station signal. Effective utilization of repeater will be very beneficial and obtain high award.For repeater design there are mainly two problems to overcome. Firstly, repeater often relays and amplifies several base station downlink signals. When repeater is introduced to CDMA system, it will cause phase confusion of base station short code, severe pilot channel pollution, and it will exacerbate unnecessary soft handoff. Even it will result in network paralysis. Secondly, if the isolation of the two antennas of the repeater is not high enough, the repeater will fall into the self-excitation. It will cause receiving and dispatching signal confusion, even make repeater system failed, neighboring base station paralysis. In order to overcome those problems, a smart repeater is proposed in this dissertation. The smart antenna is applied to resolve pilot channel pollution. A antennae array is used to a form to aim the expected base station. A new signal which is distinct from CDMA signal is added at the source, at the sink the power of the added signal is detected which is used to scale isolation.This paper is made up of 5 parts. The first part is the first chapter: the function and key feature of reapter especial CDMA repater is presented . The second part is the second chapter, which explains the system performance and implementation of the project. The third part is the third, forth chapters, which desrcibes solutions multi-base-station detection by smart antenna technique and the PN code adopted by spreading spectrum in this system and the power testing algorithm. The forth consists of the fifth, sixth chapter and the seventh chapter, which explains form the hardware of this system and presents a new CORDIC arithmetic which is developed by author. The last part is eighth chapter, the conclusion and the future development and research is proposed.