Research On OFDM Technology Used In The 4～(th) Generation Mobile Communication

Nowadays, the 4^th generation mobile communications, which base on the OFDM technology, has emerged, just shortly after several decades' development of wireless and personal communication, which has burgeoned from analog to digital and from FDMA to CDMA. It is an integrated communication system including broadband, Internet access and many other integrated functions. This paper is just going to make a study on the 4^th generation communication, concentrate on the theory analysis as well as simulation experimentation, and focus on the aspects in the OFDM system just as follow:1. This paper discusses fractal Brownian motion model which should ascribed to the fractal theory. Based on its characters, an algorithm based on the ARMA model has been put forward, which help to build a fractal Brownian motion model. Moreover, this paper qualified the validity of the algorithm by statistics distribution and statistics self-similarity of increment. Furthermore, an improved model based on the ARMA and related function has been put forward. Simulation experimentation suggests that the effect has been lift obviously.2. The tradition "simple-deal" method leads big errors between simulation experimentation and practical value. This paper adopts fractal theory into the communication channel model. Then test that the multipath fading signal has the fractal characters in the transformation process of electrical-magnetic wave because of the fractal characters of the nature. Meanwhile, the OFDM sending signal has the same expressions with the multipath fading signal, and then we draw a conclusion that the OFDM sending signal has the character of the fractal signal, and it is testified by both theory and emulation. So a new idea is found to solve the OFDM question by using wavelet transformation to restructure the OFDM signal.3. In this paper, the wavelet transformation technology is the concentration...