Cellular Mobile Communication Systems In The Frequency Of Take Up Modeling Study

Today, wireless communication is fast-developing, to making people realize spectral resources are precious with the extensive demand for frequency, but the existing method of salary distribution of fixed frequency has become the bottleneck utilizing the spectral resources of physics high-efficiently, the frequency made by NTIA(National Telecommunication and Information Administration) divides forms and can be found out, the present spectral operating position has been already quite crowded, if want to and then mean that it is unrealistic to mix the special-purpose frequency band for the new radio business in so congested frequency is divided。The cognitive radio is directed against a kind of concept change of the wireless communication system, it break traditional wireless communication meet environment passively, the static behavior uses the spectral mode fundamentally. Cognition wireless node cognitive broad sense transmit environment, intelligence and choose, transmit parameter (power, son's leading, relaying, cooperative behavior) dynamically voluntarily, use the resources of the network in coordination. The cognitive radio can regenerate spectral resources in civil communication, realize circulation applicably. In military wireless communication, can guarantee to command under the extremely abominable battle field environment, control, the connective and existence of the information network。This thesis is exactly directed against problem described above, regard cognitive radiotechnics as the main research object, through to the measurement of the spectral operating position of every frequency band, obtained it in different period data (reach some district) of business source, analyze the business source model parameter of different period. Groundwork for through measure to the wireless signal actually, mainly to GSM frequency band, TV frequency band, IS-95 frequency band carry on measurement, measure, adopt method that energy survey, record every frequency band of power value of signals, it calculate then method through statistics by all spectral power spectrum density, not take empty than, when change and probability distributions of range of land, in order to find the idle frequency band. Through measuring, the land, land characteristic frequently when we can observe what frequency spectrum is taken up, find frequency band those utilization ratio low, observe frequency spectrum how utilize at the same time, further prove the advantage of the cognitive radio.