Research On Turbo Equalization Technology For Broadband Wireless Communication Systems

With the growing requirements for bandwidth and quality of wireless communication, the research on communication techniques focused on improving the capacity of wireless communication system and the reliability of data transmission in recent years. Inter symbol interference(ISI) caused by multipath in the communication channel is a technical challenge. In broadband wireless communication systems, equalization is an important measure to combat ISI. Of all the equalization techniques, turbo equalization can integrate the resources of a system and equalize in iterative manner, which greatly improves the ability of a system in combating ISI, and therfore research of turbo equalization has important implications for broadband wireless communication systems.This thesis mainly focuses on the time domain equalization and frequency domain equalization and tries to reduce equalization complexity and improve equalization performance. In this thesis, the principles of MAP algorithm MMSE algorithm and SIC algorithm was proved by theoretical analysis and simulation in time domain, and then a low complex equalization algorithm MMSE-L was proposed on the basis of MMSE algorithm, then a comprehensive analysis and demonstration about the complexity of the proposed algorithm and basic ones was carried out, finally simulation shows that MMSE-L algorithm have very small loss of performance, therefore a great application value was proved to process by the algorithm. The principles of MMSE algorithm SIC algorithm and DFE-H algorithm was proved by theoretical analysis and simulation in frequency domain, and a high-performance equalization algorithm DFE-H-I was proposed for inhibition of the error diffusion of DFE-H algorithm in trong ISI, then a comprehensive analysis and demonstration about the complexity of the proposed algorithm and basic ones was carried out. Finally DFE-H-I algorithm was demonstrated to be able to effectively inhibit error diffusion through the simulation under moderate and severe distortion of ISI channel, and complexity of the proposed algorithm is not high, therefore a great application value was proved to process by the algorithm.