Effectiveness of directivity and polarization control SDMA systems in a cellular environment

We have proposed a novel space division multiple access (SDMA) system that employs dual-polarized antennas in both a smart antenna base station and mobile terminals (see Komiya, K. et al., Proc. 2001 IEEE 54th Veh. Technol. Conf. (VTC2001-Fall), p.1447-51, 2001). The smart antennas adaptively control radiation patterns and polarization using a dual-polarized antenna array and determine the polarization to be assigned for each mobile terminal to minimize the interference caused by other mobile terminals. This system can degrade correlation characteristics between the users. In order to clarify the effectiveness of the proposed system, vertically- and horizontally-polarized propagation are measured with narrow directions of arrival from the terminals in a cellular mobile environment, and the SDMA characteristics are evaluated in multiple user scenarios. The proposed SDMA is effective in increasing the number of users in SDMA systems for an actual cellular environment based on the measurement results.