Fmt Is In Synchronization Method Study

With the advancement of technology and the continual development of living standard, the requisition for information is more than ever. The high QoS and transmission speed in wireless communication business is highly needed in the field of voice, data and image. The broadband technologies lead the main development direction in communication field. Moreover, many transactions provided by communication systems must provide mobile services. All these put forward higher requirement for the performance of mobile communication systems.The transmittability of every kind of channel is different due to the different medium. The coherence bandwidth of wireless channels is an important factor which limits the transmittability. In built-up urban areas, multi-path fading occurs because of high surrounding structures, so there is severe intersymbol interference (ISI) which can decrease the performance of communication system. When the data rate is more than several Mbps, the ISI is generated for the signal duration is shorter than the channel delay spread. So for conventional single-carrier modulation, the system complexity will increase greatly due to the multi-taps equalizer used in high data rate wireless communication. The effect of the ISI is negligible so long as the delay spread of the multi-path channel is significantly shorter than the duration of one transmitted symbol. Therefore, multicarrier transmission technology can be used to overcome this limitation.Nowadays, Orthogonal Frequency Division Multiplexing (OFDM) is a key technology in the 4th generation mobile communication system. As one of the multicarrier transmission technologies, OFDM can reduce the multipath fading effect with high frequency efficiency. However, there are some disadvantages in OFDM system such as the sensitivity to frequency offset caused by oscillator inaccuracy and time variance of wireless channel, symbolsynchronization and high peak-to-average dynamic range of output symbols caused by summation of multiple subcarrier. All of these limit the application of OFDM in the wireless environment.Filtered Multitone (FMT) Modulation is a new multicarrier technology based on filter banks. In FMT system, the spectrum of each subchannel has a high level of spectral containment. So the inter-channel interference(ICI) is negligible compared with other noise, while it often appears in OFDM system because of its sensitivity to frequency offset. However, sub-channel equalization is needed in order to reduce the remaining ISI introduced by the filter banks. This research is inbursed by the National Natural Science Foundation of China (60372029) .In this thesis we introduce FMT transmission technology and derive the practical efficient implementation structure. In the following research, we investigate the influence of time and frequency offset. The receiver constellation and bit error rates are shown.In the chapter 3, we investigate some familiar timing synchronization schemes of multicarrier systems and schemes of FMT. We give a new timing synchronization scheme of FMT system in wireless communication and simulate the performance of some of the schemes with computer.In the chapter 4, we investigate frequency synchronization schemes of multicarrier systems. We modify SCA to accomplish frequency synchronization with only one training symbol, instead of two, without performance degradation. The redundancy of the training sequence is reduced to half. This reduction is critical especially in burst data transmission, for example, in WLAN.Because of the limitation of the time and some objective conditions, only parts of the synchronization schemes are simulated. And there are many topics which are not studied including sample timing, tracking algorithm, etc. Further study on these topics will be done in future work.