Frequency Synchronization Algorithm For MIMO-OFDM System LTE Standard Time

Currently, OFDM (Orthogonal Frequency Division Multiplexing) and Orthogonal Frequency Division Multiplexing MIMO (Multiple-Input Multiple-Output) MIMO technology has been widely used by 802.11a,802.16e system and other standards recognized as LTE (key technology long Term Evolution) communication, will be long-term evolution and application. For 4G cellular-based communications architecture, the time and frequency synchronization for MIMO-OFDM continues to be a key issue must be improved and optimized, a modern communications say hotspot. OFDM is not only in terms of improving spectrum efficiency advantages, but also for communication systems multipath interference good antagonism, and therefore in a wireless communication network communication has widely used. Since 4G communication speed, quality requirements, so how MIMO and OFDM technologies converge and play their respective advantages become a hot research. OFDM technology has high requirements for synchronous systems, and is very sensitive to synchronization error, synchronization error will cause inter-symbol interference, orthogonal subcarriers will have an impact. Synchronization system transmitting end and a receiving end for the ability to demodulate the signal correctly is critical, MIMO-OFDM system according to the position signal transmitting terminal can be divided into distributed and centralized, centralized MIMO-OFDM systematic study comparing more, relatively speaking, distributed research is lagging behind, distributed MIMO-OFDM system has its own unique advantages, such as expanding coverage of base stations, reduce the error rate, but when there is also the problem of frequency error, so for Study of frequency synchronization error has a very important practical significance when distributed MIMO-OFDM system is reduced.Firstly, timing synchronization and carrier frequency offset error For quadrature OFDM system performance impact is analyzed and discussed to determine the specific impact of error for OFDM systems.Second, to now with time domain and frequency domain of timing synchronization algorithm, based on pilot symbol timing synchronization algorithm, and the improved reverse conjugate timing synchronization algorithm are introduced and compared, for frequency synchronization algorithm for the traditional orthogonal frequency division multiplexing (OFDM) systems were are presented and compared.Finally, for the whole train of thought of the paper are summarized, and draw the conclusions and results of this thesis, for the deficiencies found in the study is proposed to research ideas and directions, the system of time and frequency synchronization estimation range reduced raised our hopes.