Effect of customer premises directional antennas on fixed wireless access systems in the downlink multipath channel

Co-channel interference (CCI) from other reuse cells restricts the channel capacity of cellular communication systems. In fixed wireless access systems, the deployment of directional antennas at the customer premises equipment (CPE) that point towards their base stations suggest a direct and easy method to combat CCI and enhance capacity in a line-of-sight (LOS) propagation scenario. However, in a non-line-of-sight (NLOS) scenario, the effect of using a directional antenna at the CPE depends on the multipath angle of arrival (AOA) distribution of the propagating channel. In this paper, we demonstrate and compare the downlink performance of the directional antenna at the CPE under different AOA conditions. Two multipath channel models are assumed: circular and elliptical scattering models. We also calculate the performance of the adaptive array antenna deployed at the CPE and calculate its beamwidth effect. The capacity performance of the adaptive array antenna is compared with that of the single directional antenna.