Soft handoff performance analysis with sectorization and transmitter diversity in CDMA systems

In a wireless communication system, the multipath fading causes deep and fast fluctuation in the received signal. To mitigate this fading effect, sectorization and smart antenna are two schemes that are widely employed in Code Division Modulation Access (CDMA) cellular systems for improving the link quality and increasing the system capacity. Soft handoff can also provide macro diversity thus improving the link quality.; In this thesis, we compare soft handoff performances of 3-sector and 6-sector CDMA systems with the single antenna in terms of soft handoff percentage, mean number of base station utilization, mean number of active set updates and outage probability. A new statistical channel model is introduced, which includes path loss, auto-correlation and cross-correlation of shadowing fading, and flat Rayleigh fading for the macrocellular systems. Due to the time varying characteristics of the propagation channels, we also analyze the soft handoff sensitivity under different propagation environments between these two systems. Within typical environmental conditions and handoff parameters, the 6-sector system has larger soft handoff percentages and active set updates, but the 3-sector system has higher diversity gains due to higher base station utilization.; We propose a novel configuration of the switched-beam smart antenna to provide both beam and polarization diversities. Soft handoff performances of this novel configuration are analyzed through the Monte Carlo simulations in the 3-sector multi-cellular systems and are compared with those of the conventional smart antenna. Compared to conventional switched-beam structure, a 2.2dB gain in signal to interference ratio is derived from soft handoff simulations in cellular CDMA systems. For a microcellular system, the deterministic channels are predicted by using the VPL ray-tracing tool. The effects of power mismatch and polarization angle distribution are analyzed. There is an approximate 6dB decrease for the single-beam selection method of both the novel and conventional configurations and a 1.2dB reduction of the double-beam selection method.