4G communication technology is the fourth generation mobile information systems, 3G technology is in a better improvement, which is a greater advantage compared to 3G communications technology, is the WLAN technology and 3G communications technology has been very good combination of the image transfer speed faster, so that the quality image transmission and image looks clearer. In the application of intelligent communications devices 4G communications technology allows users connection speed more quickly, speeds up to 100M.
Key technologies:
OFDM technology
FSK has little immunity, coding using the unipolar NRZ coding is transmitted when the transmitting end 1 is expressed at high frequencies, the transmission coding time is 0, which indicates a low frequency. If the transmission is 1011010 encoding time, encoding a waveform formed will exhibit periodicity floating. Technology utilizes OFDM transmission signal part will have some overlap, in the art will based on its analysis processor, in accordance with nuances frequency, divided into different categories of information, so as to ensure stable transmission of digital signals.
MIMO technology
MIMO mapping technique is utilized, first, the sending device will send information to a wireless carrier antenna, which after receiving the information, compile them quickly, the digital signal after the data compiled and compiled, are transmitted to the different mapping region, and then use the diversity mode and the data signal received multiplexed fusion obtain hierarchical gains.
Smart Antenna Technology
Smart antenna technology is time division multiplexing and wavelength division multiplexing technology will effectively integrate in 4G communication technology, smart antenna can achieve full coverage of the signal transmission, each antenna coverage angle is 120 °, in order to ensure full coverage, the base station transmits the at least three antennas are installed. Further, the smart antenna techniques may be implemented for adjusting the transmit signal gain effect is obtained, increasing the transmission power of the signals, it is noted that the gain regulation where the radiation angle of the antenna is not associated only increases transmission on the basis of the original power only.
SDR technology
Software radio technology is one of the common techniques of radio communication technology. Its technical idea is to broadband analog to digital converter or a digital-analog converter rf antenna sufficiently close, to complete the preparation of specific program code for band selection, sample transfer information after quantitative analysis can differentiate a selected channel modulation, and perform different security configuration, the control terminal of the selection.