he Terms of Use as given at the website. Measuring System Performance for Growth Measuring System Performance for Growth The fraction of the time the amplifier is at or above half power is an approximate measure of the forward call blocking rate. The actual threshold to use may depend on the cell itself. A coverage cell may spend quite a bit of time around half power without being in trouble, whereas a very small cell in a dense area may reach 95 percent of its maximum capacity while still at one-third power. The last 5 percent of the traffic sends a small cell scurrying up the steep part of the curve in Fig. 28.2. If forward amplifier power is being used as a criterion for blocking new calls, then we should use the sys- tem blocking level as an approximation in this section. If the busiest period of the day has this power threshold crossed 5 percent of the time, then we can presume that we have a peak-time blocking rate of 5 percent. In a conventional-reuse system (FDMA or TDMA), there is a fixed number of radio channels, and once they are full, there are no more. We can measure blocking by see- ing how often they are full, or we can measure their occupancy. The CDMA carrier ca- pacity varies with environment and call activity in nearby cells. The only way to get a firm handle on the capacity is to measure it when the system is reaching its limit. We should be keeping track of all the sectors of all the cells, if not every day, then on a regular basis. A CDMA carrier often gives little warning that it is reaching satura- tion, and the expected rapid growth of high-rate data service makes this even more likely. We recommend forward transmit power vigilance. 39.3 Reverse Power Levels Just as we can watch forward transmit power, we can keep track of reverse transmit power. The transmit power of the user terminals tells us how close the reverse direc- tion is to CDMA saturation. As in the forward direction, we want to use user terminal power levels to determine the busy-hour blocking performance of the system. If so