A Research On Cyclostationarity Signal Blind Channel Estimation In OFDM System

With the development of society, there are more and more wireless communication devices, but the resources we can provide to so many products is limited, such as bandwidth and energy. For most wireless communication systems, the most fundamental difficulties is ISI caused by multipath phenomena in the signal transmission. At the same time there is a problem that a communication system must exist a lot of users, in order to meet the communication needs of all users would inevitably produce a multi-user interference.After a number of experts and scholars study on the orthogonal frequency division multiplexing long-term found that orthogonal frequency division multiplexing has many advantages, such as frequency of Plymouth with a high effective against multipath fading and narrowband interference. This also confirmed in experiment that in OFDM system ISI and ICI can be reduced to very low, or even be completely eliminated. Then on the OFDM system, a study of channel is very necessary.This paper presents an new blind channel identification method in OFDM system-a linear time-invariant system which is excitation by cyclostationary.The basic information is used to the cycle of the output signal spectrum modulus 2πphase appropriate discretization. The whole process does not require system length information and does not require phase unwrapping. For the FIR channel is a universal given way, and for band-limited FIR channel, taking into account inherent in the frequency domain method deficiencies, proposed an approximate solution method. Simulation results show that the method of this chapter relative to the subspace method, the good performance.