The Application Study Of OFDM Hybrid Modulation Technology In High Bit-rate Wireless Data Communication

Multimedia mobile services afforded in the 4th generation wireless communication require high bit-rate transmission technology. Taking many uncertain factors in radio channel into account, the conflict is even more pungentWhile OFDM translate the high demand in time domain into the one hi frequency domain, and resolve the problem to transmit high bit-rate data in multi-path channel. However, the high demand in frequency domain involves precise synchronization both in time and frequency domain. While because of the different channel characteristics in each channel, the receiver needs some mechanisms to characterize the channel effects in coherent demodulation. They are two core problem preventing OFDM from being utilized hi wireless transmission area.This issue trying to find an OFDM transmission scheme suitable for wireless data communication while the above two problem are well settled.To estimate the channel well, we introduced a pilot signal aided modulation (PSAM) technology, and utilize certain interpolation way to get the statistical effect of channel, hence afford loss compensation for signal demodulation. We also analysis the performance of such way and get the different simulation results while using different interpolation.Considering the inaccurate timing in conventional synchronization, we invested a new synchronization schemes to resolve this problem in addition to routine synchronization. In this issue the different schemes mentioned above will be analyzed and the results are described by synchronization signal distribution intuitively.A integrated scheme combing the above two optimistic schemes is simulated and the results are afforded. The results show the scheme is of certain practical value and can be implemented based on mature technology.