Effect of directional antennas at both ends of the radio link on the Doppler Power spectrum

Generalized 3D scattering channel model with MIMO antenna systems

“…1. Note that the values Figure 11 shows the SFCs between UCA elements 1 and 2 versus the elevation angle and the distance in the proposed 3D scattering curs because, with the increase in , the PDF of the AOA at the MS becomes more and more uniform and flat [17][18]. On the other hand, for the directional antenna, by increasing the geometric height (i.e., minor axis ) of the 3D scattering region, the frequencies of the PDFs Doppler shift increase around .…”

“…Similarly, the elevation threshold angle is defi ned to separate the scattering region into two partitions in the elevation plane, i.e., (15) As discussed above, the regions defi ned by the partitions and , shown in Fig. 1, can be given as follows (16) Thus, the distances from the MS to the scattering objects located at the boundary of the scattering region can be obtained as (17) …”

“…If we decrease the beamwidth of the directional antenna used at the MS, the spread of the Doppler spectrum is reduced signifi cantly, as seen in [17]. However, when the motion is perpendicular to the line joining BS and MS ( ), most of the spectral components remain near the central frequencies.…”

“…Because 3D scattering models are more realistic regarding the behavior of multipath components in the spatial domain, the effect of directional antennas for both ends of the radio should also be thoroughly analyzed, so that more reliable wireless links can be designed for future highrate communications in time-varying mobility environments. Recently, more attention has been paid to the demand for minimizing the interference between multipath components; thus, directional antennas employed at either end of the link have been proposed [16][17]. Additionally, the performance of a wireless communication system may be enhanced by employing directional antennas at both BS and MS.…”