Analysis and Experimental Of 3 - Dimentional AOA with Directional Antenna on Narrowband MIMO Capacity

Recently, many works have considered a physical properly of antenna in MIMO channel models, such as radiation pattern effective for MIMO system. However, effect of antenna for MIMO with different algorithms is required and also with different environments of signal behavior at each end of the link. Thus, a traditional antenna such as Omni-directional antenna generally is used to design MIMO systems. In this paper, we analyze the performance of directional antenna in different environment of signal spread for multiple-inputmultiple-output (MIMO). We incorporate 3-dimensional (3D) of signal spread matching with directional antenna into a narrow-band MIMO channel model separately. This channel model allows us to investigate effect of distribution of signal coming to antenna combined with antenna radiation pattern to MIMO capacity in various propagation environments. We perform MIMO capacity simulations of a system with various antennas radiation pattern property. Uniform and peaky distribution models of angle of arrival (AOA) in azimuth and elevation planes are used in the simulations. We have shown that directional antennas reduce the narrow-band MIMO capacity when the AOA is uniformly distributed. If the AOA is peaky distributed, such as Laplacian distribution or Gaussian distribution, the narrow-band MIMO capacity is improved when the directional antennas with proper alignment to the mean AOA. However, radiation pattern will show some limitation of the antenna properties, such as gain and beam-width will affect to the capacity. This will trade off with limit an antenna for difference environment of propagation for MIMO by gain and beam-width. The proposed model is validated by narrow-band MIMO capacity measurements. Omni-directional monopole and Yagi-Uda with different gain and beam-width is used in the experiments. The experiments are performed in an anechoic chamber for reference and compared with indoor and outdoor scenario. The result verifies that the capacity with directional antenna is greater than isotropic capacity in proper scenarios.