The Analysis Of Signal Doppler Power Spectrum In MIMO Channel With Directional Antenna

Antenna technology is widely used in a variety of communication systems. According to distribution, antenna can be divided into omni-directional antenna and directional antenna. Compared to the latter one, the former is widely used. The directional antenna does not require complex algorithm, and the correlation between the directional antennas is small. So the independence of the antennas is great. Because of these advantages, there are important prospects and research value about the directional antenna.Based on MIMO channel, this paper studies the effect of signal doppler power spectrum owing to the directional antenna. And the simulation work analyzed the difference between these effects which using omni-directional antenna and directional antenna. At last, by changing the simulation environment and simulation parameters involved, these effects is simulated and analyzed.The antenna gain of omni-directional antenna is 1, and there is no direction about the omni-directional antenna. So analysis of omni-directional antenna is relatively easy. But according to the simulation results, compared to the omni-directional antenna, the using of directional antenna can significantly reduce the effect of signal doppler power spectrum. In the paper, the gain of directional antenna is normalized to 1, and the directional characteristics of directional antenna are significant. The antenna pattern function of directional antenna is simple and single in order to facilitating the calculation. For a more comprehensive simulation, MS's (Mobile users) moving direction and speed are changed. The directional antenna should not only be used in a single communications environment. In order to get different results under different communication environment, 4 typical distributions of angle of arrival is set in this paper. And different carrier frequencies are given depending on the communications environment, so that different simulation results under different communications environment can be illustrated.The use of directional antenna can reduce the effect of signal doppler power spectrum. In outdoor environment, the selection of beam that away from the BS (base station) and closing to the MS's moving direction can also reduce the effect. These conclusions above have been verified in the simulation.