Performance Comparisons of Adaptive Antenna Arrays with Fixed Multibeam Systems for TDMA Systems

In this paper, I've present uplink simulation results comparing two-element and four-element adaptive arrays with a six-sector antenna system and a fixed multibeam (four 30 degree beams per 120 degree sector with two-branch diversity in each beam) antenna system using a TDMA IS-136 modulation format and slot structure. The results consist of the capacity improvement (i.e, frequency reuse reduction) of these antenna systems over the baseline antenna system using the simulated bit error rate (BER) as the basis of comparison. The baseline antenna system is assumed to be a typical three-sector antenna system employing two-branch spatial diversity in each sector. Simulations are run for three different cell sizes and multiple reuse scenarios with the effect of antenna fading correlation and mobile station speed also considered. The results show that substantial interference suppression gains can be obtained in a small cell size (interference-dominated) system using adaptive antennas (two or four-elements) although frequency reuse reduction is not generally obtainable with the two-element array.