Research On The Technology Of The Information Transmission In The High-speed Mobile Communication

The high dynamic vehicles are the long-standing and sustained hypersonic vehicles in the space between the Satellite platform and the air space platform, of which the information transmission system is the core. So, this paper mainly makes a research on the key technology of the information transmission system.First, the characters of high-speed mobile communication channel are introduced briefly, followed by a channel model in the Ka-band. Then, the thesis makes a comprehensive analysis on the different modulation and encoding methods and introduces some modulation and encoding methods that can be used in uplink or downlink of the high-speed mobile communication system under the large Doppler frequency shift and multi-path conditions. The modulations include BPSK, QPSK, PCM-FM, SOQPSK and encoding methods mainly are1/4encoding rate of TPC code,1/2encoding rate of zero convolution code and1/2encoding rate of LDPC code. Finally, for the large dynamic Doppler frequency shift in the high-speed mobile communications, several typical Doppler estimation algorithms are introduced, including the level crossing rate(LCR) method, logarithm envelope(LE) method, covariance based(COV) method, channel power spectrum(CPS) method. The thesis also derives the best bandwidth K parameter formula in LCR algorithm. By applying the best-bandwidth filtering method to LE, COV, ACF and CPS estimation algorithms, some good performances to more accurate estimates of Doppler frequency shift can be got, which can be show by the simulation results.