channel backplane (P) 1600.00 1/100 backhaul DS-1 (P) 40000.00 10.00 Per-carrier costs 24 channels/carrier Low-power combiners 3600.00 Per-sector costs 4 carriers/sector Three antennas 9000.00 Cable and connectors 2000.00 Power amplifier 13000.00 1/2 channel backplane (P) 1600.00 Per-cell costs 3 sectors/cell Power supply 25000.00 Base station controller 50000.00 Building and climate control 120000.00 10.42 Tower 40000.00 1/2 backhaul DS-1 (P) 10000.00 Per-MSC costs 200 cells/MSC Maximum-configuration MSC 5000000.00 In our example, all the cells have three sectors. Thus each cell serves three sectors at 3840 subscribers per sector, for a total of 11,520 subscribers per cell. The per-cell costs are the big-ticket items: the $25,000 power supply, the $50,000 base station controller, $120,000 for a building and climate control, and $40,000 for the radio tower. We also have the postage-stamp component, marked with a (P) in Table 46.1, for the backhaul DS-1 that every cell requires. Our MSC costs $5,000,000 for a switch with enough capacity for 200 cells. In this ex- ample, the MSC is modular enough that the fixed-cost component is insignificant, SO an MSC equipped for 100 cells is half the price, $2,500,000. The grand total of this analysis comes to $349.46 per subscriber, 86 percent of which is the user terminal. We can consider just the system cost of $49.46 per subscriber and realize that this cost-per-subscriber estimate depends heavily on the assumption that each subscriber uses 0.02 erlang during the busy hour. If our subscribers are signifi- cantly more or less active than this, then the system cost per subscriber will change in proportion to their busy-hour usage. In this example we dealt only with the fixed cost of equipment. We aggregated the monthly costs of backhaul transport and ignored the other repeating costs, such as OA&M and equipment replacement. In a more complete cost analysis, we would con- sider the initial expense for equipment and the continuing costs as separate items. In the third-generatio