Minimum duration outages for diversity systems

Properties of time dependent outages, defined as the signal-to-interference ratio (SIR) going below a certain threshold and staying there longer than a certain "minimum duration", have been determined for Rayleigh and log-normal shadowing channels based on the received signal envelope. In this paper, we consider time dependent outages for systems with diversity reception such as antenna diversity systems and spread spectrum systems with RAKE receivers. We introduce a new notion of outage that is based on the baseband SIR after diversity combining. Results from the theory of /spl chi//sup 2/ processes are applied to derive the outage duration statistics.