Comparative Study of Fade Margins with Hard and Soft Handoff in CDMA based Microcellular Systems

摘要

In this work, an analytical approach is used to study the quantitative performance regarding the fade margins improvements, as well as cell coverage issues with hard- and soft handoff for the reverse link of a CDMA based microcellular system. To determine the required fade margins for different outage probabilities and different soft handoff scenarios, the Manhattan-like street pattern is considered. Since the analysis presented here involves the comparison of propagation losses among two or more base stations due to macroscopic selection diversity used on the reverse link, the generally accepted two slope propagation model, includes a cross-correlated shadow fading component, which allows taking into consideration the dependence between two shadowing components affecting different propagation paths, since they could experience many of the same obstructions in the path profile as has been observed in field test. From numerical evaluations, it is observed that the shadowing cross-correlation is determinant in the accuracy of handoff analysis and some suggestions regarding the fade margins are proposed for planning CDMA based microcellular systems in Manhattan environments.