Measurements of the Lost Call Rate as a Function of the Total Forward-Link Power on the Dominant Interfering Cell-Sector in a CDMA2000 Network

We have performed extensive measurements upon commercial CDMA2000 networks supporting predominantly voice services using a proprietary monitoring tool called Celnet Xplorer. These measurements capture large numbers of user-mobile calls under actual operating conditions. We also capture statistically significant number of user-mobile call failures, in particular lost calls. This massive data set allows us to correlate call failures against the network operating conditions at the same moment in time, in order to infer underlying cause and effect relationships. We observe that the call failure probability has a strong exponential dependence upon the total forward-link power on the dominant interfering cell-sector. We also conclude that the dominant physical source of this increase in lost call rate is a loss of coverage at increased load, and not loading-induced diversity reduction. We note that these results support a new paradigm where network analyses are based upon real-time measurements of actual user mobiles.