Any use is subject to the Terms of Use as given at the website. Capacity Issues Specific to CDMA Capacity and Quality Principles TABLE 30.2 CDMA Capacity Estimates for Voice and Data One-way Forward Reverse erlangs capacity capacity Erlangs Erlangs Limiting for one sector per MHz sector sector direction carrier 20 MHz per cell N = 7 AMPS Neither N = 4 GSM Neither cdmaOne Reverse 317.0 cdma200 voice Reverse 530.9 cdma2000 data Forward W-CDMA voice 130.5 157.4 Forward 119.3 504.2 W-CDMA data Forward TD-SCDMA voice Reverse 198.4 TD-SCDMA data Forward exactly 40 MHz of frequency allocation might only be able to use 15 carriers to avoid stepping on the radio neighbors' toes. Because we are confining our estimate to the saturation capacity of CDMA under small-cell, high-density conditions, we have made three other simplifications. First, we are ignoring the limitations of transmit power in both forward and reverse directions. Since a CDMA carrier runs out of capacity by running out of transmit power, this would appear to be a major oversight. However, in the saturation mode of small cells and high density, we are climbing far up the vertical asymptotes of the power curves in Figs. 28.1 and 28.2, where even large increases in available power make little difference in capacity. Second, we are ignoring any coverage advantage that multipath gives a CDMA chan- nel. Having more than one path can increase the range by increasing the power at the CDMA receiver, but it degrades the top capacity by introducing time sidelobes in the output of the rake filter. The time sidelobes affect the maximum CDMA capacity when multipath is present. Third, we have not included an independent variable for the quality of user termi- nals. The variability of the quality of user terminals can be accounted for by adjusting Eb/No or p, the variable for power-control inefficiency. Our data service example is a subscriber who is active one-fifth of the time, U = 0.2. The service is a data rate of 160 kbps with a low BER of 10-5. With rate 1/3 FEC, th